Morphological characteristics of the lumbosacral spinal cord urogenital center in Sprague Dawley rats

BACKGROUND： Studies have demonstrated that selective innervation of the sacral nerve tract to the bladder plays an important role in bladder functional reconstruction following spinal cord injury. However, there are very few studies reporting detailed morphological characteristics of urogenital center and lumbosacral nerve roots. OBJECTIVE： To analyze the spinal cord segment of the lumbosacral spinal cord urogenital center, and to observe morphological characteristics. DESIGN, TIME AND SETTING： A neuroanatomical study was performed at the Laboratory of Neuroanatomy, Peking University Health Science Center between September 2007 and March 2008. MATERIALS： Horseradish peroxidase-conjugated cholera toxin B subunit （CB-HRP） was purchased from Sigma, USA; surgical microscope was purchased from Zhenjian Zhongtian Optical Instrument, Jiangsu Province, China; BCL-420 biological and functional experimental system was purchased from Taimeng Science and Technology, Sichuan Province, China. METHODS： A total of 36 adult, Sprague Dawley rats were randomly assigned to groups A （n = 10）, B （n = 10）, C （n = 10）, and D （n = 6）. CB-HRP （3%, 10-15 μL） was injected into the bladder detrusor muscle （group A）, external urethral sphincter （group B）, and perineal muscles （group C）, respectively. Rats in group D were not given any treatments. MAIN OUTCOME MEASURES： At 72 hours after CB-HRP injection, CB-HRP-positive neurons were analyzed in lumbosacral segments using 3, 3＇, 5, 5＇-tetramethylbenzidine staining and an Olympus optic microscope, while anatomical structures in the respective spinal nerve tract were observed using a surgical microscope. RESULTS： CB-HRP-positive neurons were distributed in the L6-S1 segments of the spinal cord, and neurons primarily innervating the bladder detrusor muscle were located at the sacral parasympathetic nucleus and the intermediolateral nucleus. In addition, neurons that primarily innervate the external urethral sphincter and perineal muscles were observed in the ventrolateral portion （Onuf＇s nucleus）. The lumbar-sacral nerve roots were composed of varying nerve tracts, Le., they were typically divided into 1-2 sub-bundles, and the sub-bundles were then divided into 2-3 tiny bundles. There were extensive fibro-connections between the rootlets. CONCLUSION： The urogenital center in Sprague Dawley rats was located in the L6 -S1 segments of the spinal cord, and the rootlets were clearly observed. Therefore, this rat experimental model could be utilized for highly selective anterior/posterior rhizotomy.

Anti-hypercholesterolemic effect of kenaf(Hibiscus cannabinus L.)seed on high-fat diet Sprague dawley rats

Objective:To determine? the anlihypercholesterolemic effects of kenaf seed samples and compare with the commercial hypocholesterolemic drug on serum lipids profiles and malondialdehyde(MDA) level in the rat.Methods:Kenaf seed oil(KSO),microencapsulated kenaf seed oil(MKSO),kenaf seed extract(KSE) and defatted kenaf seed meal(DKSM) were prepared and phytocHemicals screening on these samples were done prior in viro study.Phenolic compounds in KSF.were quantified using high performance liquid chromatography.There were 40(divided in eight diet groups of 5) male Sprague dawley rats adapted lo normal standard diet or hypercholesterolemic diet(HD) with or without the treatment of these kenaf samples for 32 days.Results:All the kenaf samples exhibited to contain most of the major phytocliemicals.KSE possessed gallic acid,tannic acid,catechin.benzaldehyde.benzoic acid,syringic acid,sinapic acid,ferulic acid,naringin acid,and protocatechuic acid.The significant higher(P<0.05) serum total cholesterol,low density lipoprotein cholesterol and MDA levels in HD group without treatment than the normal control group suggested the hypercholesterolemia was induced by the Incorporation of cholesterol into diet.KSE exhibited higher cholesterol-lowering properties due to the significant lower(P<0.05)in serum triglycerides,total cholesterol and MDA levels.KSF showed the highest efficiency of cholesterol-lowering activity,followed by KSO.MKSO and DKSM.Conclusions:DKSM.MKSO.KSO and KSE appeared lo have comparable anti-hypercholesterolemic effect with the commercial hypocholesterolemic drug.Hence,kenaf seed could be used as an alternative natural source lo replace the synthetic hypocholosterolemic drugs.

Analysis of Behaviour Pattern in Sprague-Dawley Rats Using Microwave Techniques

This communication presents a new method of detecting the behaviour pattern in Sprague-Dawley (SD) rats based on the measurement of the dielectric properties of blood plasma at microwave frequencies at different periods of time. The microwave measurements were performed by rectangular cavity perturbation method in the S-band of microwave frequency with the blood plasma collected from normal rats (Controls) as well as chemically induced rats (A&beta;). A change is observed in the dielectric properties of the A&beta;samples but not the controls samples at the extended period of time. This measurement technique is simple and the collection of blood from the rats is nonsurgical in nature. These results prove a new method of diagnosing Alzheimer’s Disease (AD) using microwave techniques.

Magnetic resonance imaging of hepatocellular carcinoma induced by diethylnitrosamine in Sprague-Dawley rats

Diethylnitrosamine (DENA) is able to induce various benign and malignant liver lesions in rats with a high success rate and a low mortality rate. It provides a more appropriate model that better simulates the various lesions occurring in humans than the usual model of tumor implantations. The aim of the present study was to evaluate MRI liver examination in Sprague-Dawley(SD) rats as a routine method to detect hepatocellular carcinoma (HCC) nodules induced by DENA and to follow up their growth. METHODS:Hepatic carcinogenesis was induced in 80 male SD rats using oral DENA solution. All animals were imaged for liver tumor detection with a 1.5 Tesla magnet (Siemens Sonata,Erlangen, Germany) using correspondence scan parameters and a radio-frequency knee coil. Macroscopic examinations were performed along the axial MRI sections to evaluate magnetic resonance imaging (MRI) findings, and histopathological assessment was also performed. RESULTS:No false negative results were obtained on MR images. Hepatic tumors in 72 rats were confirmed macro-scopically and 68 rats were detected by MRI till the 20th week. The smallest and the largest nodules detected by MRI were 2 mm and 37 mm in diameter respectively. The agreement rate of MRI with macroscopic observation was 39. 1% and 97. 4% respectively for 2 mm to 5 mm and more than 5 mm nodules. CONCLUSIONS:The hepatic tumor induced by DENA provides a more representative range of tumors for imaging diagnosis and interventional treatment. MRI is the best approach for scrutinizing pathological changes of rat livers in the period of observation.

Analysis of transcriptome sequencing of sciatic nerves in Sprague-Dawley rats of different ages

An aging-induced decrease in Schwann cell viability can affect regeneration following peripheral nerve injury in mammals. It is therefore necessary to investigate possible age-related changes in gene expression that may affect the biological function of peripheral nerves. Ten 1-week-old and ten 12-month-old healthy male Sprague-Dawley rats were divided into young（1 week old） and adult（12 months old） groups according to their ages. mRNA expression in the sciatic nerve was compared between young and adult rats using next-generation sequencing（NGS） and bioinformatics（n = 4/group）. The 18 groups of differentially expressed mRNA（DEmRNAs） were also tested by quantitative reverse transcription polymerase chain reaction（n = 6/group）. Results revealed that（1） compared with young rats, adult rats had 3608 groups of DEmRNAs. Of these, 2684 were groups of upregulated genes, and 924 were groups of downregulated genes. Their functions mainly involved cell viability, proliferation, differentiation, regeneration, and myelination.（2） The gene with the most obvious increase of all DEmRNAs in adult rats was Thrsp（log2 FC = 9.01, P 〈 0.05）, and the gene with the most obvious reduction was Col2 a1（log2 FC = -8.89, P 〈 0.05）.（3） Gene Ontology analysis showed that DEmRNAs were mainly concentrated in oligosaccharide binding, nucleotide-binding oligomerization domain containing one signaling pathway, and peptide-transporting ATPase activity.（4） Analysis using the Kyoto Encyclopedia of Genes and Genomes showed that, with increased age, DEmRNAs were mainly enriched in steroid biosynthesis, Staphylococcus aureus infection, and graft-versus-host disease.（5） Spearman＇s correlation coefficient method for evaluating NGS accuracy showed that the NGS results and quantitative reverse transcription polymerase chain reaction results were positively correlated（rs = 0.74, P 〈 0.05）. These findings confirm a difference in sciatic nerve gene expression between adult and young rats, suggesting that, in peripheral nerves, cells and the microenvironment change with age, thus influencing the function and repair of peripheral nerves.

Reference values for selected hematological, biochemical and physiological parameters of Sprague‐Dawley rats at the Animal House, Faculty of Medicine, University of Colombo,Sri Lanka

Background: Lack of available reference values in a research setting under local conditions can be a drawback for beginners, as the accuracy of data from control samples cannot be checked at the beginning of a research project. This affects comparisons with data from test samples. To avoid these complications in their research projects,beginners tend to have a greater number of animals in the control group compared to test groups in order to have control group measurements within 2 SDs of the mean.Methods: As non-availability of reference values was a long-felt need, the described project was conducted in order to establish a reference database for selected haematological, biochemical and physiological parameters using apparently healthy Sprague-Dawley rats bred in the Animal House of Faculty of Medicine, University of Colombo(UCFM).Results: Differences in mean values of packed cell volume(PCV), mean corpuscular volume(MCV) and mean corpuscular hemoglobin concentration(MCHC), serum creatinine and blood glucose levels between the two genders were statistically significant. Lipid profile measurements did not differ significantly between genders, but mean and median values of triglycerides(TG) between male and female rats showed a difference of more than 10 mg/dL. The liver enzymes alkaline phosphatase(AP)and aspartate aminotransferase(AST) were also statistically significantly different between sexes. Despite wide variation in mean alanine aminotransferase(ALT)between sexes, the difference was not statistically significant.Conclusion: The findings of this project should support to a certain extent the"Reduction" aspect of the 3 Rs concept of Russell and Burch by reducing the number of Sprague-Dawley rats used in future research projects at UCFM.

Morphometric study on Leydig cells in capsulotomized testis of rats

AIM: To further clarify the changes occurred in the testicular capsulotomized rats. METHODS: In testicular capsulotomized and sham-operated rats, the cross sectional area, the nucleus diameter and the number of Leydig cells were morphologically analyzed by the Vidas Image Processing System connected to a microscope. RESULTS: In the capsulotomized animals, the cross sectional area of Leydig cells was gradually increased from 30 days onwards. There was no obvious change in the nucleus diameter of Leydig cells. However, The Leydig cell number was significantly increased from day 30 onwards. CONCLUSION: In rats, testicular capsulotomy may induce hyperplasia/hypertrophy of Leydig cells in the testis.

Study on Action of Acupuncture on Ventromedial Nucleus of Hypothalamus in Obese Rats

Effects of acupuncture on the spontaneous discharge of nerve cells and levels of monoamine neurotransmitters in ventromedial nucleus of hypothalamus (VMH) of the obese rats were investigated. Results indicated that the levels of tyrosine (Tyr) and dopamine (DA) were lowered, the levels of 5-hydroxytryptamine (5-HT) and 5-hydoxyindole acetic acid (5-HIAA) increased, and the frequency of the spontaneous discharge of nerve cells in VMH lowered in the obese rat group as compared with the normal group. When acupuncture obtained the effect of weight reduction, the frequency of spontaneous discharges of nerve cells in VMH were markedly increased, and the levels of Tyr, DA and tryptamine (Typ) and 5-HT/5-HIAA ratio elevated, and the 5-HT level lowered. It is suggested that the virtuous regulative action of acupuncture on VMH might be one of the key factors in acupuncture for weight reduction.

Effect of Batroxobin on Neuronal Apoptosis During Focal Cerebral Ischemia and Reperfusion in Rats

We have found that Batroxobin plays a protective role in ischemic brain injury, which attracted us to investigate the effect of Batroxobin on apoptosis of neurons during cerebral ischemia and reperfusion. The apoptotic cells in ischemic rat brains at different reperfusion intervals were tested with method of TdT-mediated dUTP-DIG nick end labeling (TUNEL) and the effect of Batroxobin on the apoptosis of neurons was studied in left middle cerebral artery (LMCA) occlusion and reperfusion in rat models (n = 18). The results showed that few scattered apoptosis cells were observed in right cerebral hemispheres after LMCA occlusion and reperfusion, and that a lot of apoptosis cells were found in left ischemic cortex and caudoputamen at 12 h reperfusion, and they reached peak at 24 h-48 h reperfusion. However, in the rats pretreated with Batroxobin, the number of apoptosis cells in left cerebral cortex and caudoputamen reduced significantly and the neuronal damage was much milder at 24 h reperfusion than that of saline-treated rats. The results indicate that administration of Batroxobin may reduce the apoptosis of neurons induced by cerebral ischemia and reperfusion and afford significant cerebroprotection in the model of focal cerebral ischemia and reperfusion.

Metabolic Changes in Rats with Photochemically Induced Cerebral Infarction and the Effects of Batroxobin:A Study by Magnetic Resonance Imaging,~1H-and ^(31)p-Magnetic Resonance Spectroscopy

Metabolic changes in rats with photochemically induced cerebral infarction and the effects of batroxobin were investigated 1, 3, 5 and 7 days after infarction by means of magnetic resonance imaging (MRI), 1H- and 31P-magnetic resonance spectroscopy (MRS). A region of T2 hyperintensity was observed in left temporal neocortex in infarction group and batroxobin group 1, 3, 5 and 7 days after infarction. The volume of the region gradually decreased from 1 day to 7 days after infarction. The ratio of NAA/Cho + Cr in the region of T2 hyperintensity in the infarction group was significantly lower than that in the corresponding region in the sham-operated group 3, 5 and 7 days after infarction respectively (P

The Regulatory Action of Radix Astragali on M-Cholinergic Receptor of the Brain of Senile Rats

The changes in density of M-cholinergic receptors in different areas of senile rats and the regulatory action of Huang Qi ([symbol: see text] Radix Astragali, a drug for warming yang and replenishing qi) were observed by autoradiography. The results showed that the gray scale displayed in brain sections was clear and mainly distributed in the cortex, hippocampus and striate body, while that due to nonspecific combination was negligible. The gray scale in the cortex, hippocampus and striate body of the experimental group was markedly lower than that in the young control rats, decreased respectively by 24.87%, 14.12% and 12.76% (all P

Effect of Stimulation of Shenshu Point on the Aging Process of Genital System in Aged Female Rats and the Role of Monoamine Neurotransmitters

In this experiment, among some aged female rats aged over 18 months, and young female rats aged 3 months whose central noradrenergic nerve endings were injured by ventricular injection of 6-hydroxy-dopamine (6-OHDA), it was observed that catgut embedding at bilateral Shenshu (UB 23) points could obviously shorten sexual cycles, increase the frequency of sexual cycle, and slow down the aging process of the genital system in both the aged rats and in the rats with injured noradrenergic endings. After electroacupuncture (EA) at Shenshu (UB 23) points in the aged rats, the frequency of neuronal discharges in locus coeruleus (LC) was elevated and the activating rate of LC to neurons in the medial preoptic area (MPOA) of the hypothalamus was increased, while obvious effect on nucleus raphes magnus (NRM) and the effect of NRM on MPOA were not marked. It is suggested that stimulation of Shenshu (UB 23) point can strengthen the excitability of noradrenergic neurons, activate the ascending pathway of the brain stem - hypothalamus, raise the catecholamine (CA)/5-hydroxytryptamine (5-HT) ratio in the hypothalamus of the aged rats, so as to delay the aging process of the genital system.

Evaluation of the Haematinic Activities of Extracts of <i>Justicia secunda</i>Vahl Leaves in Red Blood Cells of Laboratory Rats

The use of plant parts (leaves, flowers, stems, barks, roots etc.) in traditional medicine is increasingly gaining ground in modern medicine, as plant sources have long been recognized as sources of secondary metabolites which can be used to treat a wide range of diseases. The effect of extracts of Justicia secunda leaves on red blood cells (RBC) count and haemoglobin (Hb) concentration was investigated in adult Sprague-Dawley rats to establish haematinic activity. Phenylhydrazine (PHZ)-induced anaemic rats were treated with water, methanol or ethyl acetate extracts at 200 mg/kg body weight. RBC counts and Hb concentration were analysed using a haematology analyser at 3-day intervals for 21 days. The extracts were compared with rats administered the haematinic tonic Feroglobin&reg;?and vehicle-treated (normal saline). Rats administered the water extract exhibited the most significant increase (P ) in the number of RBCs and Hb concentration compared with the vehicle-treated PHZ-induced anaemic rats. Rats administered the methanol extract followed with significant increase (P ) in RBC counts and Hb concentration (J. secunda leaves has excellent haematinic properties and this provides the pharmacological basis of its use in Ghanaian traditional medicine for the treatment of anaemia.

Effects of Extracellular ATP on Survival of Sensory Neurons in the Dorsal Root Ganglia of Rats

ATP was added to the cultured sensory neurons obtained from the dorsal root ganglia of the neonatal rats and PBS was added to serve as control. MTT assays were conducted to evaluate the survival and activity of the cultured neurons. And the silicone regenerative chamber was used after the sciatic nerve incision of the mature SD rat. 1 mmol/L ATP was injected into the left chamber and 0.09 % natrium chloride was injected into the right chamber as controls. The changes of nitric oxide synthase (NOS) activity in the corresponding dorsal root ganglia were measured histochemically and image analysis was also performed 4 days after the sciatic nerve injury. The results showed that extracellular ATP could enhance the survival of the neurons and the number of NOS positive neurons were significantly different between the ATP and control groups ( P <0.05). It was suggested that extracellular ATP had neurotrophic effect on neurons survival and could inhibit the NOS activity of the sensory neurons after the peripheral nerve incision, hence exerting the protective effect on the neurons, which was valuable for nerve regeneration after nerve injury.

Selective control by posterior spinal nerve roots of micturition and erection in rats

The posterior rootlets in L6 and S1 spinal cord of adult male Sprague-Dawley rats underwent electrostimulation. The bladder pressure, urethral perfusion pressure and intracavernous pressure were recorded. When some posterior rootlets of L6 and Sl were electrostimulated, the intracavernous pressure peaked rapidly, but the bladder pressure and the urethral perfusion pressure curve did not show great change. When other rootlets were stimulated, the bladder pressure changed greatly, but the urethral perfusion pressure and the intracavernous pressure did not show great change. When different rootlets were stimulated, the urethral perfusion pressure changed maximally, but there were no great changes in bladder pressure or intracavernous pressure. Furthermore, stimulation of some rootlets produced simultaneous changes in two or three different pressure measures mentioned above. The results demonstrate that regulation by L6 and S1 posterior rootlets of the rat bladder detrusor, external urethral sphincter and penis cavernous body are significantly distinct. Different rootlets can be distinguished by electrostimulation.

Combined Subchronic Toxicity of Bisphenol A and Dibutyl Phthalate on Male Rats

Objective To evaluate the combined subchronic toxicity of bisphenol A（BPA） and dibutyl phthalate（DBP） in male Sprague Dawley（SD） rats.Methods Forty 4‐week‐old male rats weighing 115‐125 g were randomly divided into BPA‐treated,DBP‐treated group,BPA＋DBP‐treated and control groups and fed with a soy‐ and alfalfa‐free diet containing 285.4 ppm BPA,285.4 ppm DBP,285.4 ppm BPA plus 285.4 ppm DBP,and a control diet,respectively,for 90 consecutive days.At the end of the study,the animals were sacrificed by exsanguination via the carotid artery under diethyl etherane aesthesia and weighed.Organs,including liver,kidneys,spleen,thymus,heart,brain,and testis underwent pathological examination.The androgen receptor（AR）,gonadotropin‐releasing hormone receptor（GNRHR）,and progesterone hormone receptor（PR） genes from the hypothalamus were detected by real‐time PCR.The biomedical parameters were analyzed.Results No significant difference was found in food intake,body weight,tissue weight,organ/brain weight ratio,and biomedical parameters among the four groups（P〉0.05）.However,BPA and DBP up‐regulated AR,PR and GNRHR expression levels in rats and showed a synergistic or an additive effect in the BPA＋DBP group.Conclusion The combined subchronic toxicity of BPA and DBP is synergistic or additive in male SD rats.

Expression of TNF-α and VEGF in the esophagus of portal hypertensive rats

AIM: To investigate the expression of tumor necrosis factor-alpha (TNF-α) and vascular endothelial growth factor (VEGF) in the development of esophageal varices in portal hypertensive rats. METHODS: Thirty male Sprague-Dawley (SD) rats in the model group in which a two-stage ligation of portal vein plus ligation of the left adrenal vein was performed, were divided into three subgroups (M7, M14, and M21) in which the rats were kiued on the seventh day, the 14th d and the 21 d after the complete portal ligation. Thirty male SD rats, which underwent the sham operation in the control group, were also separated into three subgroups (C7, C14 and C21) corresponding to the models. The expression of TNF-α and VEGF in the esophagus of all the six subgroups of rats were measured with immunohistochemical SP technique. RESULTS: The portal pressure in the three model subgroups was significantly higher than that in the corresponding control subgroups (23.82±1.83 vs 11.61±0.86 cmH2O, 20.90±3.27 vs11.43±1.55 cmH2O and 20.68±2.27 vs 11.87±0.79 cmH2O respectively, vs P<0.01), as well as the number (9.3±1.6 vs 5.1?.8, 11.1±0.8 vs 5.4±1.3 and 11.7±1.5 vs 5.2?.1 respectively, P<0.01) and the total vascular area (78 972.6±3 527.8 vs 12 993.5±4 994.8 μm2, 107 207.5±4 6461.4 vs 11 862.6±5 423.2 μm2 and 110 241.4±49 262.2 vs 11 973.7±3 968.5 μm2 respectively, P<0.01) of submucosal veins in esophagus. Compared to the corresponding controls, the expression of TNP-α and VEGF in M21 was significantly higher (2.23±0.30 vs 1.13±0.28 and 1.65±0.38 vs 0.56±0.30 for TNF-α and VEGF respectively, P <0.01), whereas there was no difference in M7(1.14±0.38 vs 1.06±0.27 and 0.67±0.35 vs 0.50±0.24 for TNPa and VEGF respectively, P>0.05) and M14 (1.20±0.25 vs 1.04±0.26 and 0.65±0.18 vs 0.53±0.25 for TNF-α and VEGF respectively, P>0.05). And the expression of TNF-α and VEGF in M21 was significantly higher than that in M7 (2.23±0.30 vs1.14±0.38 and 1.65±0.38 vs 0.67±0.35 for TNF-α and VEGF respectively, P<0.01) and M14(2.23±0.30 vs 1.20±0.25 and 1.65±±0.38 vs 0.65±0.18 for TNF-a and VEGF respectively, P<0.01), but there was no difference between M7and M14(1.14±0.38 vs1.20±0.25 and 0.67±0.35 vs 0.65±0.18 for TNF-α and VEGF respectively, P>0.05). CONCLUSION: In the development of esophageal varices in portal hypertensive rats, increased TNF-α and VEGF may be not an early event, and probably play a role in weakening the esophageal wall and the rupture of esophageal varices.

Keladi candik(Alocasia longiloba Miq.) petiole extracts promote wound healing in a full thickness excision wound model in rats

Objective: To investigate the wound-healing effect of Alocasia longiloba(A. longiloba) petiole extract on wounds in rats.Methods: Twenty-two male Sprague-dawley rats were randomly assigned to receive 10% solcoseryl gel, phosphate buffer saline, 50% ethanol, 95% ethanol and hexane extracts of A. longiloba at 1.5%, 3% and 6% doses, respectively. A full thicknesses wound(6 mm) was created on the dorsal of the rat; and all rats were applied with the extract solutions, 10% solcoseryl gel and phosphate buffer saline once a day topically until day 12. The wound was photographed on day 1, 6 and 12, and the percentage of wound contraction was calculated. On day 12, rats were sacrificed and histological examination of granulation tissue was carried out using haematoxylin & eosin and Masson's Trichrome stain to determine the wound healing effect.Results: In this study, 6% of 50% and 95% ethanol extracts of A. longiloba showed 82.50% and 82.32% wound contraction, respectively, and were comparable with 10% solcoseryl gel(82.30%). Meanwhile, phosphate buffer saline treated group showed the lowest wound contraction(69.86%). Histological assessment of wound treated with 6% of 95% ethanol extract of A. longiloba showed distinct epidermal and dermal layer, higher proliferation of fibroblast and more angiogenesis with collagen compared to other wound treated groups.Conclusions: A. longiloba petiole extracts have a wound healing potential and 6% of 95% ethanol extract of A. longiloba is more effective. Further studies are required to understand the wound healing mechanism of action of the extract.

Electroacupuncture alleviates stress-induced visceral hypersensitivity through an opioid system in rats

AIM:To investigate whether stress-induced visceral hypersensitivity could be alleviated by electroacupuncture(EA) and whether EA effect was mediated by endogenous opiates.METHODS:Six to nine week-old male SpragueDawley rats were used in this study.Visceral hypersensitivity was induced by a 9-d heterotypic intermittent stress(HIS) protocol composed of 3 randomly stressors,which included cold restraint stress at 4?℃ for 45 min,water avoidance stress for 60 min,and forced swimming stress for 20 min,in adult male rats.The extent of visceral hypersensitivity was quantified by electromyography or by abdominal withdrawal reflex(AWR) scores of colorectal distension at different distention pressures(20 mmHg,40 mmHg,60 mmHg and 80 mmHg).AWR scores either 0,1,2,3 or 4 were obtained by a blinded observer.EA or sham EA was performed at classical acupoint ST-36(Zu-San-Li) or BL-43(Gao-Huang) in both hindlimbs of rats for 30 min.Naloxone(NLX) or NLX methiodide(m-NLX) was administered intraperitoneally to HIS rats in some experiments.RESULTS:HIS rats displayed an increased sensitivity to colorectal distention,which started from 6 h(the first measurement),maintained for 24 h,and AWR scores returned to basal levels at 48 h and 7 d after HIS compared to pre-HIS baseline at different distention pressures.The AWR scores before HIS were 0.6 ± 0.2,1.3 ± 0.2,1.9 ± 0.2 and 2.3 ± 0.2 for 20 mmHg,40 mmHg,60 mmHg and 80 mmHg distention pressures,respectively.Six hours after termination of the last stressor,the AWR scores were 2.0 ± 0.1,2.5 ± 0.1,2.8 ± 0.2 and 3.5 ± 0.2 for 20 mmHg,40 mmHg,60 mmHg and 80 mmHg distention pressures,respectively.EA given at classical acupoint ST-36 in both hindlimbs for 30 min significantly attenuated the hypersensitive responses to colorectal distention in HIS rats compared with sham EA treatment [AWRs at 20 mmHg:2.0 ± 0.2 vs 0.7 ± 0.1,P = 4.23 711 E-4;AWRs at 40 mmHg:2.6 ± 0.2 vs 1.5 ± 0.2,P = 0.00 163;AWRs at 60 mmHg:3.1 ± 0.2 vs 1.9 ± 0.1,P = 0.003;AWRs at 80 mmHg:3.6 ± 0.1 vs 2.4 ± 0.2,P = 0.0023;electromyographic(EMG) at 20 mmHg:24 ± 4.7 vs 13.8 ± 3.5;EMG at 40 mmHg:60.2 ± 6.6 vs 30 ± 4.9,P = 0.00 523;EMG at 60 mmHg:83 ± 10 vs 39.8 ± 5.9,P = 0.00 029;EMG at 80 mmHg:94.3 ± 10.8 vs 49.6 ± 5.9,P = 0.00 021].In addition,EA at the acupuncture point BL-43 with same parameters did not alleviate visceral hypersensitivity in HIS rats.EA in healthy rats also did not have any effect on AWR scores to colorectal distention at distention pressuresof 20 and 40 mmHg.The EA-mediated analgesic effect was blocked by pretreatment with NLX in HIS rats [AWR scores pretreated with NLX vs normal saline(NS) were 2.0 vs 0.70 ± 0.20,2.80 ± 0.12 vs 1.50 ± 0.27,3 vs 2.00 ± 0.15 and 3.60 ± 0.18 vs 2.60 ± 0.18 for 20 mmHg,40 mmHg,60 mmHg and 80 mmHg;P = 0.0087,0.0104,0.0117 and 0.0188 for 20,40,60 and 80 mmHg,respectively].Furthermore,EA-mediated analgesic effect was completely reversed by administration of m-NLX,a peripherally restricted opioid antagonist(EMG pretreated with m-NLX vs NS were 30.84 ± 4.39 vs 13.33 ± 3.88,74.16 ± 9.04 vs 36.28 ± 8.01,96.45 ± 11.80 vs 50.19 ± 8.28,and 111.59 ± 13.79 vs 56.42 ± 8.43 for 20 mmHg,40 mmHg,60 mmHg and 80 mmHg;P = 0.05 026,0.00 034,0.00 005,0.000 007 for 20 mmHg,40 mmHg,60 mmHg and 80 mmHg,respectively).CONCLUSION:EA given at classical acupoint ST-36 alleviates stress-induced visceral pain,which is most likely mediated by opioid pathways in the periphery.

Effect of Alligator Pepper on Litter Weight of Rats Fed on High Glycemic Index Diet

This study was carried out to find out if alligator pepper can prevent the development of fetal macrosomia in Sprague-Dawley rats fed with high glycemic index diet. Fifteen adult female Sprague-Dawley rats of proven fertility were acclimatized for a period of two weeks in a well-ventilated laboratory and fed with grower’s mash and water ad libitum. Thereafter, they were randomly placed in separate cages after which a male Sprague-Dawley rat of proven fertility was introduced into each of the cages containing the female rats. They were left in the cages for three days during, which mating was confirmed to have occurred. The male rats were then withdrawn from the female rats, which were placed in separate maternity cages. The female rats were randomly allocated to three groups A, B and C so there were 5 pregnant rats in each group. The rats in group A were fed with 50 g of grower’s mash daily while the rats in groups B and C were fed with 50 g of cooked fermented cassava respectively. All rats were given water ad libitum throughout the duration of the experiment. The rats in groups A and B were intraperitoneally injected with 13.3 ml per Kg body weight of distilled water while the rats in group C were intraperitoneally injected with 13.3 mg/Kg body weight of aqueous extract of alligator pepper respectively. They were observed for 18 - 25 days. The litters of the rats in group B had a significantly higher mean weight than the rats in group A while the litters of the rats in group C had a significantly lower mean weight than the rats in groups B. It was concluded that intraperitoneally injected aqueous extract of alligator pepper, in the first trimester of pregnancy, can prevent the development of fetal macrosomia in Sprague-Dawley rats.