Synphilin-1 siRNA increases superoxide dismutase expression in a rat model of Parkinson’s disease

BACKGROUND： Synphilin-1 has been shown to be involved in the pathogenesis of Parkinson＇s disease （PD）, and superoxide dismutase （SOD） reduction might induce PD onset. To date, the precise effect of synphilin-1 on SOD expression remains poorly understood. OBJECTIVE： To explore the influence of synphilin-1 small interfering RNA （siRNA） on SOD expression in a rat model of PD. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Laboratory of Neurology, Affiliated Hospital of Qingdao University Medical School from June to October 2008. MATERIALS： 6-hydroxydopamine was purchased from Wuhan Boster, China. METHODS： A total of 40 male, Wistar rats were randomly assigned to PD, siRNA, siRNA negative control, and control groups, with 10 rats in each group. Rats from the PD, siRNA, and siRNA negative control groups were injected with 6-hydroxydopamine into the right substantia nigra to establish PD models. In addition, synphilin-1 siRNA and siRNA negative control sequences were separately injected into the right substantia nigra of siRNA, and siRNA negative control groups. The control group rats were treated with a mixture of ascorbic acid and normal saline. MAIN OUTCOME MEASURES： Synphilin-1 and SOD protein and mRNA expression in the substantia nigra was detected by immunohistochemistry and in situ hybridization. RESULTS： Synphilin-1 and SOD protein and mRNA expression were significantly decreased in PD and siRNA negative control groups （P 〈 0.05）. However, the siRNA group exhibited opposite effects. CONCLUSION： Synphilin-1 resulted in altered SOD expression, which suggested a protective role for synphilin-1 siRNA in an animal model of PD.

Zhichan decoction induces differentiation of dopaminergic neurons in Parkinson's disease rats after neural stem cell transplantation

The goal of this study was to increase the dopamine content and reduce dopaminergic metabolites in the brain of Parkinson’s disease rats. Using high-performance liquid chromatography, we found that dopamine and dopaminergic metabolite（dihydroxyphenylacetic acid and homovanillic acid） content in the midbrain of Parkinson’s disease rats was increased after neural stem cell transplantation ＋ Zhichan decoction, compared with neural stem cell transplantation alone. Our genetic algorithm results show that dihydroxyphenylacetic acid and homovanillic acid levels achieve global optimization. Neural stem cell transplantation ＋ Zhichan decoction increased dihydroxyphenylacetic acid levels up to 10-fold, while transplantation alone resulted in a 3-fold increment. Homovanillic acid levels showed no apparent change. Our experimental findings show that after neural stem cell transplantation in Parkinson’s disease rats, Zhichan decoction can promote differentiation of neural stem cells into dopaminergic neurons.

Electroacupuncture-regulated neurotrophic factor mRNA expression in the substantia nigra of Parkinson's disease rats

Acupuncture for the treatment of Parkinson＇s disease has a precise clinical outcome. This study investigated the effect of electroacupuncture at Fengfu （GV16） and Taichong （LR3） acupoints in rat models of Parkinson＇s disease induced by subcutaneous injection of rotenone into rat neck and back. Reverse transcription-PCR demonstrated that brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor mRNA expression was significantly increased in the substantia nigra of rat models of Parkinson＇s disease, and that abnormal behavior of rats was significantly improved following electroacupuncture treatment. These results indicated that electroacupuncture treatment upregulated brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor mRNA expression in the substantia nigra of rat models of Parkinson＇s disease. Thus, electroacupuncture may be useful in the treatment of Parkinson＇s disease.

Parallel relationship between microglial activation and substantia nigra damage in a rotenone-induced Parkinson's disease rat model

BACKGROUND： Inflammatory injury induced by microglial activation plays an important role in the occurrence and development of Parkinson＇s disease （PD）. However, few studies have examined the relationship between microglia and substantia nigra damage or dopaminergic neuron loss in animals with rotenone-induced PD.OBJECTIVE： To explore the relationship between activated microglia and loss of the substantia nigra, and the changes in concentration and dose of rotenone in the brain of rats with rotenone-induced PD.DESIGN, TIME AND SETTING： The neuropathological experiment was performed at the School of Traditional Chinese Medicine, Capital Medical University, China, from July 2007 to July 2008. MATERIALS： Rotenone was purchased from Sigma, USA. METHODS： The Parkinson＇s model was induced by injection of a rotenone oily-emulsion （2 mg/kg daily） subcutaneously into the back of 58 male adult Wistar rats for 3-6 weeks. Another three rats served as normal controls.MAIN OUTCOME MEASURES： Neurobehavioral changes were observed and recorded following rotenone treatment. Tyrosine hydroxylase and complement receptor OX42 were separately analyzed by immunohistochemical staining within 4 weeks following stopping rotenone treatment. Rotenone content was measured using high performance liquid chromatography in the cerebellum of rats that scored 2.4-6.RESULTS： Rotenone induced a loss of dopaminergic neurons in the substantia nigra as well as microglial activation, with increased behavior scores. Dopaminergic loss was still ongoing even when rotenone was stopped. Dopaminergic neuronal degeneration in the substantia nigra was initially 6%, but was 85% at 2 weeks after scoring, and degeneration depended on activated microglia. Rotenone was detected in the cerebellum at concentrations between 78.9 μg/L and 309.6 μg/L. CONCLUSION： Nigrostriatal dopaminergic degeneration paralleled the microglial activation. Rotenone absorbed into the brain in its original form initiated pathological injury in the substantia niara of PD rats.

Bacterial melanin in rat models of Parkinson's disease: a potential neuroprotective strategy

Melanins are widely used in medicine, pharmacology and cosmetics. Different technologies have been used to obtain melanin including： chemical synthesis based on oxidation of tyrosine and its derivatives; extraction from animal materials; alkaline extraction from plant material; and microbiological synthesis. A few number of works have been published that were focused on purification of water insoluble 3,4-dihy- droxy-phenylalanine-melanins （Kukulianskaia et al., 2002）. The majority of synthetic and natural melanins are insoluble in wa- ter that significantly complicates preparation of pharmacolog- ical and cosmetic preparations. Obtaining of low-cost soluble biotechnological melanin can speed up application of melanin in medicine and other fields. For the first time, melanin-syn-thesizing strain with high level of pigment synthesis - Bacillus thuringiensis was obtained. The ecologically safe technology of biosynthesis, isolation and purification of the bacterial melanin has been elaborated.

Divalent metal transporter 1 expression and iron deposition in the substantia nigra of a rat model of Parkinson's disease

Extensive iron deposition has been observed in the midbrain substantia nigra （SN） of Parkinson＇s disease （PD） patients, but the mechanisms of iron deposition in the SN remain poorly understood. The present study investigated the relationship between dopaminergic neuronal damage, iron content changes, and divalent metal transporter 1 （DMT1） in the midbrain SN of PD rats to explore the relationship between time of iron deposition and DMT1 expression. Frozen midbrain SN sections from model rats were stained with Perls＇ iron. Results showed massive loss of tyrosine hydroxylase （TH）-positive cells in the SN and increased DMT1 expression in model group rats. No obvious iron deposition was observed in the SN during early stages after damage, but significant iron deposition was detected at 8 weeks post-injury. Results demonstrate that the loss of TH-positive cells in the SN appeared simultaneously with increased DMT1 expression. Extensive iron deposition occurred at 8 weeks post injury, which could be regarded as an early time window of iron deposition.

Monoamine alterations and rotational asymmetry in a rat model of Parkinson's disease following lateral ventricle transplantation of human amniotic epithelial cells

BACKGROUND： Human amniotic epithelial cells （HAECs） can differentiate into neurons, astrocytes and oligodendrocytes. They biologically secrete many active neurotrophins and have the capacity to metabolize dopamine enzymes. These features underlie a theoretical basis for the treatment of Parkinson＇s disease （PD）. OBJECTIVE： To investigate the survival and differentiation of transplanted HAECs in the lateral ventricle of PD model rats, and to explore its effect on circling behavior, as well as levels of dopamine （DA）, the metabolite homovanillic acid, dihydroxyphenyl acetic acid, 5-hydroxyindoleacetic acid, and 5-hydroxytryptamine in the striatum. DESIGN, TIME AND SETTING： A randomized, controlled, animal study was performed at the Institute of Biochemistry and Cell Biology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, and Shanghai Celstar Institute of Biotechnology from May 2007 to December 2008. MATERIALS： HAECs were derived from the placental chorion following caesarean delivery at the Shanghai International Matemal and Child Health Hospital. 6-hydroxydopamine （6-OHDA）, and mouse anti-human Vimentin monoclonal antibody were purchased from Sigma, USA; mouse anti-human nestin and tyrosine hydroxylase （TH） monoclonal antibodies were purchased from Chemicon, USA. METHODS： A total of 114 healthy, adult, Sprague Dawley rats were randomly assigned to two groups： PD model [n = 90, stereotactic microinjection of 2 μL 6-OHDA （3.5 μg/uL） into the striatum] and control （n = 24, no treatment）. The 51 successful PD model rats were randomly divided into 3 subgroups （n = 17）： HAEC, PBS, and model. The HAEC and PBS groups were respectively injected with 10 μL PBS solution containing 1 × 10^5/mL HAECs or 10 pL PBS into the lateral ventricle. The model group was not treated. MAIN OUTCOME MEASURES： TH protein expression in the striatum was evaluated by immunohistochemistry 5 weeks after HAEC transplantation. At 10 weeks, HAEC survival in the lateral ventricle was investigated by immunofluorescent staining; differentiation of HAECs in the lateral and third ventricles was examined by TH immunohistochemistry; concentrations of DA, homovanillic acid, dihydroxyphenyl acetic acid, 5-hydroxyindoleacetic acid, and 5-hydroxytryptamine in the striatum, as well as DA concentration in the cerebrospinal fluid, were measured with high-performance liquid chromatography-electrochemical detection. Circling behavior of PD model rats was consecutively observed for 10 weeks following intraperitoneal injection of amphetamine 1 week after successful model establishment. RESULTS： tn the HAEC group, the number of TH-positive cells significantly increased in the striatum, and circling behavior significantly decreased, compared with the PBS and model groups （P 〈 0.01）. In addition, monoamine concentrations in the striatum, as well as DA concentrations in the cerebrospinal fluid, significantly increased, compared with the PBS group （P 〈 0.05-0.01）. Moreover, a large number of nestin-, vimentin-, and TH-positive cells were observed in the lateral and third ventricles following HAEC injection.CONCLUSION： HAECs survived for 10 weeks with no overgrowth following transplantation into the lateral ventricle of PD model rats. Moreover, the cells differentiated into dopaminergic neurons, which increased DA secretion. HAEC transplantation improved cycling behavior in PD model rats.

Expression of calbindin D28K in substantia nigra of model rats with Parkinson disease

BACKGROUND： Previous researches suggested that expression level of calbindin D28K mRNA decreased in substantia nigra （SN） of model rats with Parkinson disease （PD）, and this might be related to the decrease of anti-degeneration potentials of dopaminergic neurons. OBJECTIVE： To observe expression changes of calbindin D28K in SN dopaminergic neurons during their degeneration and death in midbrain of PD model rats. DESIGN： Completely randomized grouping design SETTING： Department of Neurobiology, Xuzhou Medical College MATERIALS＂ A total of 92 healthy male SD rats, with the age of 3 months, weighing 200-250 g, were selected from Experimental Animal Center of Xuzhou Medical College [certification： SCXK （su） 2003-0003]. Calbindin D28K（CB）, tyroxine hydroxylase （TH）, ABC kit, 6-hydroxydopamine （6-OHDA） and Nissl dyes were provided by Sigma Company, and sheep serum was provided by Beijing Zhongshan Company. METHODS： The experiment was carried out in the Neurobiological Center of Xuzhou Medical College from October 2003 to October 2004. ① With lot method, rats were divided into blank control group （n=28）, experimental control group （n=-28） and experimental group （n=36）. Rats in experimental group were injected with 6-OHDA at right corpus striatum for PD modeling; rats in experimental control group were injected with saline at the same site; rats in blank control group did not give any injections.② On the 7^th, 14^th, 21^st and 28^th days, SN segments on right midbrain from every 5 rats in experimental group were fixed, embedded with paraffin and cut into successively coronary pieces. Rats in other two groups were treated with the same methods and then stained with Nissl to show neuronal form. Meanwhile, CB and TH antibodies staining with immunohistochemistry were used to show CB containing dopaminergic neurons and dopaminergic neurons, and cells were calculated and observed under optic microscope. ③ On the 14^th and 28^th days, every 4 rats in experimental group and every 4 rats in control group were selected to obtain their brains and separate SN on the injured side. Western blot was used to detect expression of calbindin D28K, protein band was scanned with imaging equipment, and data were analyzed with LabWorks software. MAIN OUTCOME MEASURES：① On the 7^th, 14^th, 21^st and 28^th days, Nissl staining results of SN neurons and immunohistochemical staining results of CB and TH antibodies; ② On the 14^th and 28^th days, Western blot results of calbindin D28K in SN neurons, RESULTS; Among 92 rats, 2 rats in experimental group died after 1 day due to 6-OHDA injection and other 90 rats were involved in the final analysis. ①Nissl staining results： On the 7^th day of 6-OHDA injection, most neuronal somas on right SN pars compacta were shown as deep pycnosis or lysis breakage; on the 14^th and 21^st days, amount of neurons was decreased remarkably; on the 28^th day, most neurons in SN pars compacta disappeared. ② Results of immunohistochemical staining： Amount of positive neurons of calbindin D28K in right SN pars compacta was not changed on the 7^th day after 6-OHDA injection; on the 14^th day, the amount was higher in experimental group than that in both control groups （P 〈 0.01） and was decreased till the 21^st day, but it was still higher than that in the two control groups （P 〈 0.05）; on the 28^th day, positive neurons of calbindin D28K nearly disappeared, and the amount was lower than that in the two control groups （P 〈 0.01）. In addition, on the 7^th day after 6-OHDA injection into corpus striatum, positive TH neurons decreased 24% in right SN, and there was significant difference from that in control groups; on the 14^th, 21^st and 28^th days, positive TH neurons decreased 37%, 46% and 64%, respectively. ③ Western blot results： On the 14＇h day after 6-OHDA injection into corpus striatum, expression of calbindin D28K in right SN was higher in experimental group than that in both control groups （P 〈 0.05）; however, on the 28^th day, the expression was lower than that in the two control groups （P 〈 0.01 ）. CONCLUSION ： During degeneration and death of dopaminergic neurons, CB expression in SN pars compacta increases firstly and decreased gradually.

LDN-73794 Attenuated LRRK2-Induced Degeneration in a <i>Drosophila</i>Parkinson’s Disease Model

Parkinson’s disease (PD) is a common neurodegenerative disease with unclear pathogenesis. Currently, there are no disease-modifying neuron-protecting drugs to slow down the neuronal degeneration. Mutations in the leucine-rich repeat kinase 2 (LRRK2) cause genetic forms of PD and contribute to sporadic PD as well. Disruption of LRRK2 kinase functions has become one of the potential mechanisms underlying disease-linked mutation-induced neuronal degeneration. To further characterize the pharmacological effects of a reported LRRK2 kinase inhibitor, LDN-73794, in vitro cell models and a LRRK2 Drosophila PD model were used. LDN-73794 reduced LRRK2 kinase activity in vitro and in vivo. Moreover, LDN-73794 increased survival, improved locomotor activity, and suppressed DA neuron loss in LRRK2 transgenic flies. These results suggest that inhibition of LRRK2 kinase activity can be a potential therapeutic strategy for PD intervention and LDN-73794 could be a potential lead compound for developing neuroprotective therapeutics.

Feasibility of establishing model of Parkinson disease by injecting 6-hydroxydopamine at different parts of the nigrostriatal pathway in the brain of rats

BACKGROUND： Previous researches found that animal models with Parkinson disease （PD） could be established by injecting 6-hydroxydopamine （6-OHDA） into medial forebrain bundle （MFB）, substantia nigra compacta （SNC） and caudate-putamen complex （CPU） of the nigrostriatal pathway. OBJECTIVE ： To compare behavioral, biochemica 6-OHDA injections in the areas of MFB, SNC and DESIGN： Controlled observational study and histological properties of these rats undergoing the CPU respectively. SEI-IING： Department of Neurology, First Affiliated Hospital of Guangxi Medical University MATERIALS： A total of 64 adult female SD rats weighing 180-230 g were provided by the Animal Experimental Center of Guangxi Medical University. 6-OHDA （Sigma Company, USA）; Brain solid positioner （Standard model 51600, Stoelting Co., IL, USA）; rotational monitoring of little animal （type QL-1, USA）; high liquid chromatography （HLC, Waters Company）. METHOOS： The experiment was carried out in the Medical Experimental Center of Guangxi Medical University from February to December 2005. ① According to digital table, 64 SD rats were divided into MFB group, SNC group, CPU group and control group with 16 in each group. On the basis of the brain atlas of Paxinos, rats in the first three groups were injected with 5 μL 6-OHDA into right MFB （0 mm of line of incisor tooth, A/P 4.4 mm, L/R 1.2 mm, ON -7.8 mm）, SNC （line of incisor tooth just equal to horizon, A/P -4.8 mm, L/R 1.6 mm, ON -7.8 mm） and CPU （0 mm of line of incisor tooth, A/P 1.2 mm, L/R 2.7 mm, ON -5.4 mm）, respectively. The rats in control group were injected with 5 μL ascorbic acid solution （2 g/L）. One week after operation, 0.1 g/L apomorphine （Apo, 0.05 mg/kg） was subcutaneously injected into neck and then rotational behavior induced by Apo was recorded once a week for 8 weeks. The PD models were considered successful only when rotational times more than or equal to 7 times per minute. Eight weeks after operation, micro-perfusion was used to obtain micro-perfusate in bilateral CPU and contents of 3,4-dihydroxyphenylacetic acid （3,4-DOPAC） and homovanillic acid （HVA） were also measured. In addition, amount of tyrosine hydroxylase positive cells （TH＊） in SNC was counted with immuno- histochemical staining. MAIN OUTCOME MEASURES ： ① Successful rate of PD models; ② contents of dopamine and its metabolite in MFB, SNC and CPU groups and TH＊ amount. RESULTS： All 64 SD rats were involved in the final analysis. ③ Successful rate and rotational behavior： One week after operation, there were 6 successful models both in SNC and MFB groups; in the 2^nd week, there were 6 both in SNC and MFB groups and 1 in CPU group; in the 3^nd week, there were 1 in MFB group and 3 in CPU group; in the 4^nd week, there were 3 in CPU group. Otherwise, no successful case was found out in the next 3 weeks. Abnormal rotational behavior was not observed in control group. Four weeks after operation, successful rates were 81% （13/16） in MFB group, 75% （12/16） in SNC group and 44% （7/16） in CPU group.② Contents of 3, 4-DOPAC and HVA： Eight weeks after operation, contents in the SNC area of the injured side were lower than those on non-lesion side （P 〈 0.01）.③Changes of TH＋ amount： Eight weeks after operation, TH＋ amount in the SNC area of the lesion side was lower than that on non-lesion side （P 〈 0.01 ）. CONCLUSION： Injecting 6-OHDA into MFB, SNC and CPU can damage dopaminergic cells and establish successful PD models.

Melatonin ameliorates microvessel abnormalities in the cerebral cortex and hippocampus in a rat model of Alzheimer’s disease

Melatonin can attenuate cardiac microvascular ischemia/reperfusion injury,but it remains unclear whether melatonin can also ameliorate cerebral microvascular abnormalities.Rat models of Alzheimer’s disease were established by six intracerebroventricular injections of amyloidbeta 1–42,administered once every other day.Melatonin(30 mg/kg)was intraperitoneally administered for 13 successive days,with the first dose given 24 hours prior to the first administration of amyloid-beta 1–42.Melatonin ameliorated learning and memory impairments in the Morris water maze test,improved the morphology of microvessels in the cerebral cortex and hippocampus,increased microvessel density,alleviated pathological injuries of cerebral neurons,and decreased the expression of vascular endothelial growth factor and vascular endothelial growth factor receptors 1 and 2.These findings suggest that melatonin can improve microvessel abnormalities in the cerebral cortex and hippocampus by lowering the expression of vascular endothelial growth factor and its receptors,thereby improving the cognitive function of patients with Alzheimer’s disease.This study was approved by the Animal Care and Use Committee of Jinzhou Medical University,China(approval No.2019015)on December 6,2018.

Therapeutic potential of dental pulp stem cell transplantation in a rat model of Alzheimer’s disease

Dental pulp stem cells are dental pulp-derived mesenchymal stem cells that originate from the neural crest.They exhibit greater potential for the treatment of nervous system diseases than other types of stem cells because of their neurogenic differentiation capability and their ability to secrete multiple neurotrophic factors.Few studies have reported Alzheimer’s disease treatment using dental pulp stem cells.Rat models of Alzheimer’s disease were established by injecting amyloid-β1–42 into the hippocampus.Fourteen days later,5×106 dental pulp stem cells were injected into the hippocampus.Immunohistochemistry and western blot assays showed that dental pulp stem cell transplantation increased the expression of neuron-related doublecortin,NeuN,and neurofilament 200 in the hippocampus,while the expression of amyloid-βwas decreased.Moreover,cognitive and behavioral abilities were improved.These findings indicate that dental pulp stem cell transplantation in rats can improve cognitive function by regulating the secretion of neuron-related proteins,which indicates a potential therapeutic effect for Alzheimer’s disease.This study was approved by the Animal Ethics Committee of Harbin Medical University,China(approval No.KY2017-132)on February 21,2017.

Structural and molecular features of intestinal strictures in rats with Crohn's-like disease

AIM: To develop a new rat model we wanted to gain a better understanding of stricture formation in Crohn&#x02019;s disease (CD).METHODS: Chronic colitis was induced locally by the administration of 2,4,6-trinitrobenzenesulfonic acid (TNBS). The relapsing inflammation characteristic to CD was mimicked by repeated TNBS treatments. Animals were randomly divided into control, once, twice and three times TNBS-treated groups. Control animals received an enema of saline. Tissue samples were taken from the strictured colonic segments and also adjacent proximally and distally to its 60, 90 or 120 d after the last TNBS or saline administrations. The frequency and macroscopic extent of the strictures were measured on digital photographs. The structural features of strictured gut wall were studied by light- and electron microscopy. Inflammation related alterations in TGF-beta 2 and 3, matrix metalloproteinases 9 (MMP9) and TIMP1 mRNA and protein expression were determined by quantitative real-time PCR and western blot analysis. The quantitative distribution of caspase 9 was determined by post-embedding immunohistochemistry.RESULTS: Intestinal strictures first appeared 60 d after TNBS treatments and the frequency of them increased up to day 120. From day 90 an intact lamina epithelialis, reversible thickening of lamina muscularis mucosae and irreversible thickening of the muscularis externa were demonstrated in the strictured colonic segments. Nevertheless the morphological signs of apoptosis were frequently seen and excess extracellular matrix deposition was recorded between smooth muscle cells (SMCs). Enhanced caspase 9 expression on day 90 in the SMCs and on day 120 also in myenteric neurons indicated the induction of apoptosis. The mRNA expression profile of TGF-betas after repeated TNBS doses was characteristic to CD, TGF-beta 2, but not TGF-beta 3 was up-regulated. Overexpression of MMP9 and down-regulation of TIMP1 were demonstrated. The progressive increase in the amount of MMP9 protein in the strictures was also obvious between days 90 and 120 but TIMP1 protein was practically undetectable at this time.CONCLUSION: These findings indicate that aligned structural and molecular changes in the gut wall rather than neuronal cell death play the primary role in stricture formation.

Visceral hypersensitivity and altered colonic motility after subsidence of inflammation in a rat model of colitis

AIM:Irritable bowel syndrome(IBS)is a functional bowel disorder characterized by visceral hypersensitivity and altered bowel motility.There is increasing evidence suggesting the role of inflammation in the pathogenesis of IBS,which addresses the possibility that formerly established rat model of colitis could be used as an IBS model after the inflammation subsided. METHODS:Colitis was induced by intracolonic instillation of 4% acetic acid in male Sprague-Dawley rats.The extent of inflammation was assessed by histological examination and myeloperoxidase(MPO)activity assay.After subsidence of colitis,the rats were subjected to rectal distension and restraint stress,then the abdominal withdrawal reflex and the number of stress-induced fecal output were measured, respectively. RESULTS:At 2 days post-induction of colitis,the colon showed characteristic inflammatory changes in histology and 8-fold increase in MPO activity.At 7 days post-induction of colitis,the histological features and MPO activity returned to normal.The rats at 7 days post-induction of colitis showed hypersensitive response to rectal distension without an accompaning change in rectal compliance,and defecated more stools than control animals when under stress.CONCLUSION: These results concur largely with the characteristic features of IBS, visceral hypersensitivity and altered defecation pattern in the absence of detectable disease, suggesting that this animal model is a methodologically convenient and useful model for studying a subset of IBS.

Changes of CD8+CD28-T regulatory cells in rat model of colitis induced by 2,4-dinitrofluorobenzene

AIM:To determine the changes of CD8+ T subsets especially CD8+CD28-T regulatory cells in rat model of experimental colitis induced by 2,4-dinitrofluorobenzene (DNFB). METHODS:The rat model of experimental colitis was induced by enema with DNFB.Ten days later,colonic intraepithelial and splenic lymphooltes were isolated from colitis animals (n=16) and controls (n=8).The proportion of CD8+ T cells,CD8+CD28+ T cells and CD8+CD28-T regulatory cells were determined by flow cytometry. RESULTS:The model of experimental colitis was successfully established by DNFB that was demonstrated by bloody diarrhea,weight loss and colonic histopathology.The proportion of CD8+ T cells in either splenic or colonic intraepithelial lymphocytes was not significantly different between colitis animals and controls (spleen:34.6±7.24 % vs 33.5±9.41%, colon:14.0±8.93 % vs 18.0±4.06 %,P>0.05).But CD8+CD28- T regulatory cells from colitis animals were significantly more than those from controls (spleen:11.3±2.26 % vs 5.64±1.01%, colon:6.50±5.37 % vs 1.07±0.65 %,P<0.05).In contrast, CD8+CD28+ T cells from colitis animals were less than those from controls (spleen:23.3±6.14 % vs 27.8±9.70 %,P=0.06; colon:7.52±4.18 % vs 16.9±4.07 %,P<0.05).The proportion of CD8+CD28-T regulatory cells in splenic and colon intraepithelial CD8+ T cells from colitis animals was higher than that from controls (spleen:33.3±5.49 % vs 18.4±7.26 %, colon:46.0±14.3 % vs6.10±3.72 %,P<0.005). CONCLUSION:Experimental colitis of rats can be induced by DNFB with simplicity and good reproducibility.The proportion of CD8+CD28-T regulatory cells in rats with experimental colitis is increased,which may be associated with the pathogenesis of colitis.

Short-term versus long-term water maze training effects on hippocampal neuronal synaptic plasticity in a rat model of senile dementia

BACKGROUND： Changes in synaptic plasticity might underlie senile dementia, and might be the neurobiological basis for learning and memory dysfunctions in patients with Alzheimer＇s Disease. OBJECTIVE： To investigate the effects of water maze training on hippocampal neuronal synaptic plasticity in rats with senile dementia, and to compare changes in synaptic plasticity between short- and long-term water maze training sessions. DESIGN, TIME AND SETTING： A randomized, controlled, neuromorphological observation with animal models of senile dementia was performed at the laboratory of College of Pharmacy, Chongqing Medical University between November 2006 and April 2007. MATERIALS： Fifty male, Sprague Dawley rats were randomized into five groups, with 10 rats per group： model, control, sham-operated, short-term water maze training, and long-term water maze training. METHODS： In the model group, senile dementia was induced by fimbria-fornix lesion method. The control rats remained untreated. In the sham-operated group, water maze training was performed without fimbria-fomix lesion induction. Rats from the short-term water maze training group underwent 20-day water maze training from day 26 after fimbria-fornix lesion induction. The long-term water maze training group underwent 40-day water maze training beginning at day 6 following fimbria-fornix lesion induction. Beginning at day 41, each group underwent 5-day spatial learning and memory training. MAIN OUTCOME MEASURES： Following experimentation, the morphological parameters of synapses, including synaptic numerical density, synaptic surface density, and the average synapse size were stereologically measured. Through the use of an electron microscope, synaptic morphological changes in the hippocampal CA3 region were observed. RESULTS： Compared with the control group, synaptic numerical and surface densities were significantly decreased in the model group （P 〈 0.01）. Synaptic numerical and surface densities significantly increased in the short- and long-term water maze training groups, compared with the model group （P 〈 0.01 ）, and these values were also significantly greater in the long-term water maze training group than in the short-term water maze training group. The model group exhibited larger average sizes of synaptic conjunctions, compared with the control group （P 〈 0.01）. Synaptic conjunction size was significantly less in the short- and long-term water maze training groups than in the model group （P 〈 0.01 ）, and the long-term water maze training group exhibited smaller synaptic conjunction sizes compared with the short-term water maze training group （P 〈 0.05）. Synaptic morphological changes in the hippocampal neurons were in accordance with stereological measurements. CONCLUSION： Water maze training increased synaptic numerical and surface densities in the hippocampal CA3 region, resulting in numerical and functional changes in synaptic plasticity in rats with senile dementia. Long-term water maze training resulted in better therapeutic effects than short-term water mate training.

Involvement of CRH Receptors in the Neuroprotective Action of R-Apomorphine in the Striatal 6-OHDA Rat Model

The dopamine D1-D2 receptor agonist, R-apomorphine, has been shown to be neuroprotective in different models of Parkinson’s disease. Different mechanisms of action for this effect have been proposed, but not verified in the striatal 6-hydroxydopamine rat model. In this study, the expression of a set of genes involved in 1) signaling, 2) growth and differentiation, 3) neuronal regeneration and survival, 4) apoptosis and 5) inflammation in the striatum was measured after a subchronic R-apomorphine treatment (10 mg/kg/day, subcutaneously, during 11 days) in the striatal 6-hydroxydopamine rat model. The expression of 84 genes was analysed by using the rat neurotrophins and receptors RT2 ProfilerTM PCR array. The neuroprotective effects of R-apomorphine in the striatal 6-hydroxydopamine model were confirmed by neurochemical and behavioural analysis. The expression data suggest the observed neuroprotection involved the alteration of the gene and the protein expression levels of the anti-inflammatory corticotropin releasing hormone receptor (CRHR) 1 and the pro-inflammatory CRHR2 receptor confirming its potential anti-inflammatory action.

Effects of glycyrrhetinic acid on collagen metabolism of hepatic stellate cells at different stages of liver fibrosis in rats

INTRODUCTIONLiver fibrosis is a dynamic course leading tocirrhosis from a various chronic liver diseases. Thepathological basis of fibrosis is the disturbance ofproduction and degradation of the extracellularmatrix (ECM), which causes accumulation of ECMin the liver[1,2].

Inhibiting effect of antisense oligonucleotides phosphorthioate on gene expression of TIMP-1 in rat liver fibrosis

AIM: To observe the inhibition of antisense oligonucleotides (asON) phosphorthioate to the tissue inhibitors metalloproteinase-1 (TIMP-1) gene and protein expression in the liver tissue of immunologically induced hepatic fibrosis rats. The possibility of reversing hepatic fibrosis through gene therapy was observed. METHODS: Human serum albumin (HSA) was used to attack rats, as hepatic fibrosis model, in which asONs were used to block the gene and protein expressing TIMP-1. According to the analysis of modulator, structure protein, coding series of TIMP-1 genome, we designed four different asONs. These asONs were injected into the hepatic fibrosis models through coccygeal vein. The results was observed by RT-PCR for measuring TIMP-1 mRNA expression, immunohistochemistry and in situ hybridization for collagen I, II, special staining of collagen fiber, and electron microscopic examination. RESULTS: Hepatic fibrosis could last within 363 days in our modified model. The expressing level of TIMP-1 was high during hepatic fibrosis process. It has been proved by the immunohistochemical and the electron microscopic examination that the asON phosphorthioate of TIMP-1 could exactly express in vivo. The effect of colchicine was demonstrated to inhibit the expressing level of mRNA and the content of collagen I, III in the liver of experimental hepatic fibrosis rats. However, the electron microscopy research and the pathologic grading of hepatic fibrosis showed that there was no significant difference between the treatment group and the model group (P】 0.05). CONCLUSION: The experimental rat model of hepatic fibrosis is one of the preferable models to estimate the curative effect of anti-hepatic fibrosis drugs. The asON phosphorthioate of TIMP-1 could block the gene and protein expression of TIMP-1 in the liver of experimental hepatic fibrosis rats at the mRNA level. It is possible to reverse hepatic fibrosis, and it is expected to study a new drug of antihepatic fibrosis on the genetic level. Colchicine has very limited therapeutic effect on hepatic fibrosis, furthermore, its toxicity and side effects are obvious.

Gastrin,somatostatin,G and D cells of gastric ulcer in rats

AIM: To investigate the relationship among gastrin, somatostatin, G and D cells in gastric ulcer and in its healing process in rats. METHODS: Fourty-nine Wistar rats were divided into 7 groups. The gastric ulcer model was induced by acetic acid successfully. The gastrin and the somatostatin in rat plasma, gastric fluid and antral tissue were measured by radioimmunoassay(RIA). G and D cells in antral mucosa were analyzed with polyclonal antibody of gastrin and somatostatin by immunohistochemical method and Quantimet 500 image analysis system. RESULTS: In gastric ulcer, the level of gastrin in plasma, gastric fluid, and antral tissue increased, that of somatostatin declined, and the disorder gradually recovered to the normal level in the healing process. Immunohistochemical technique of G and D cells in antral mucosa demonstrated that the number of G cells increased and that of D cells decreased, both areas of G and D cells declined, the ratio of number and area of G/D increased in gastric ulcer, and the disorder gradually recovered in the healing process. CONCLUSION: In gastric ulcer, the increased gastrin secreted by G cells, the declined somatostatin secreted by D cells, and the disordered G/D cell ratio can lead to gastrointestinal dysfunction.