Pterostilbene Ameliorates Glycemic Control,Dyslipidemia and Liver Injury in Type 2 Diabetes Rats

Type 2 diabetes mellitus(T2DM)is typified by the increment of chronic blood glucose levels that is caused by an absolute and/or a relative deficiency of insulin,accounts for 90%of diabetes and causes a range of complications[1].

Identifying the stability of housekeeping genes to be used for the quantitative real-time PCR normalization in retinal tissue of streptozotocin-induced diabetic rats

AIM:To investigate the stability of the seven housekeeping genes:beta-actin(ActB),glyceraldehyde-3-phosphate dehydrogenase(GAPDH),18s ribosomal unit 5(18s),cyclophilin A(CycA),hypoxanthine-guanine phosphoribosyl transferase(HPRT),ribosomal protein large P0(36B4)and terminal uridylyl transferase 1(U6)in the diabetic retinal tissue of rat model.METHODS:The expression of these seven genes in rat retinal tissues was determined using real-time quantitative reverse transcription polymerase chain reaction(RT-qPCR)in two groups;normal control rats and streptozotocininduced diabetic rats.The stability analysis of gene expression was investigated using geNorm,NormFinder,BestKeeper,and comparative delta-Ct(ΔCt)algorithms.RESULTS:The 36B4 gene was stably expressed in the retinal tissues of normal control animals;however,it was less stable in diabetic retinas.The 18s gene was expressed consistently in both normal control and diabetic rats’retinal tissue.That this gene was the best reference for data normalisation in RT-qPCR studies that used the retinal tissue of streptozotocin-induced diabetic rats.Furthermore,there was no ideal gene stably expressed for use in all experimental settings.CONCLUSION:Identifying relevant genes is a need for achieving RT-qPCR validity and reliability and must be appropriately achieved based on a specific experimental setting.

Protective effect of liraglutide on the myocardium of type 2 diabetic rats by inhibiting polyadenosine diphosphate-ribose polymerase-1

BACKGROUND In recent years,studies have found that the occurrence and development of diabetic cardiomyopathy(DCM)is closely related to an increase in polyadenosine diphosphate-ribose polymerase-1(PARP-1)activity.PARP-1 activation could be involved in the pathophysiological process of DCM by promoting oxidative stress,the inflammatory response,apoptosis and myocardial fibrosis.AIM To investigate the mechanism of liraglutide in improving myocardial injury in type 2 diabetic rats,further clarified the protective effect of liraglutide on the heart,and provided a new option for the treatment of DCM.METHODS Forty healthy male SD rats aged 6 wk were randomly divided into two groups,a normal control group(n=10)and a model group(n=30),which were fed an ordinary diet and a high-sugar and high-fat diet,respectively.After successful modeling,the rats in the model group were fed a high-glucose and high-fat diet for 4 wk and randomly divided into a model group and an intervention group(further divided into a high-dose group and a low-dose group).The rats were fed a high-glucose and high-fat diet for 8 wk and then started drug intervention.Blood samples were collected from the abdominal aorta to detect fasting blood glucose and lipid profiles.Intact heart tissue was dissected,and its weight was used to calculate the heart weight index.Haematoxylin and eosin staining was used to observe the pathological changes in the myocardium and the expression of PARP-1 in the heart by immunohistochemistry.RESULTS The body weight and heart weight index of rats in the model group were significantly increased compared with those in the normal control group,and those in the intervention group were decreased compared with those in the model group,with a more obvious decrease observed in the high-dose group(P<0.05).In the model group,myocardial fibers were disordered,and inflammatory cells and interstitial fibrosis were observed.The cardiomyopathy of rats in the intervention group was improved to different degrees,the myocardial fibers were arranged neatly,and the myocardial cells were clearly striated;the improvement was more obvious in the high-dose group.Compared with the normal control group,the expression of PARP-1 in myocardial tissue of the model group was increased,and the difference was statistically significant(P<0.05).After liraglutide intervention,compared with the model group,the expression of PARP-1 in myocardial tissue was decreased,and the reduction was more obvious in the high-dose group(P<0.05)but still higher than that in the normal control group.CONCLUSION Liraglutide may improve myocardial injury in type 2 diabetic rats by inhibiting the expression of myocardial PARP-1 in a dose-dependent manner.

Effect of angiotensin Ⅱ type 1 receptor blocker and angiotensin converting enzyme inhibitor on the intraocular growth factors and their receptors in streptozotocin-induced diabetic rats

AIM： To investigate the effect of angiotensin II type 1 receptor blocker （ARB） and angiotensin converting enzyme inhibitor （ACEI） on intraocular growth factors and their receptors in streptozotocin-induced diabetic rats. METHODS： Forty Sprague-Dawley rats were divided into 4 groups： control, diabetes mellitus （DM）, candesartan- treated DM, and enalapril-treated DM （each group, n---10）. After the induction of DM by streptozotocin, candesartan [ARB, 5 mg/（kg · d）] and enalapril [ACEI, 10 mg/（kg · d）] were administered to rats orally for 4Wko Vascular endothelial growth factor （VEGF） and angiotensin II （Ang II） concentrations in the vitreous were measured using enzyme-linked immunosorbent assays, and VEGF receptor 2 and angiotensin II type 1 receptor （ATIR） levels were assessed at week 4 by Western blotting. RESULTS： Vitreous Ang II levels were significantly higher in the DM group and candesartan-treated DM group than in the control （P=0.04 and 0.005, respectively）. Vitreous ATIR increased significantly in DM compared to the other three groups （P〈0.007）. Candesartan-treated DM rats showed higher vitreal ATIR concentration than the enalapril-treated DM group and control （P〈0.001 and P=0.005, respectively）. No difference in vitreous Ang II and ATIR concentration was found between the enalapril- treated DM group and control. VEGF and its receptor were below the minimum detection limit in all 4 groups. CONCLUSION： Increased Ang II and ATIR in the hyperglycemic state indicate activated the intraocular renin-angiotensin system, which is inhibited more effectively by systemic ACEI than systemic ARB.

Danhong Huayu Koufuye combined with metformin attenuated diabetic retinopathy in Zucker diabetic fatty rats

AIM: To evaluate effects of Danhong Huayu Koufuye (DHK, a Chinese medicinal formulae) alone or combined with metformin on diabetic retinopathy (DR) in Zucker diabetic fatty (ZDF) rats, an animal model of obese type -2 diabetes, and then to investigate the mechanisms. METHODS: ZDF (fa/fa) rats were administered with vehicle (distilled water), metformin, DHK, and DHK plus metformin. Electrophysiological and histological analysis were applied to evaluated effects of DHK alone or combined with metformin on DR. The levels of fasting blood glucose (FBG) and glycosylated hemoglobin (HbA1c) in blood were measured to evaluate the antihyperglycemic activity of DHK. Furthermore, levels of nitric oxide (NO), malondialdehyde (MDA) and activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) in serum were measured to study effects of DHK on oxidative stress in ZDF rats. In addition, body weight, lipidic indexes and insulin level were also assessed. RESULTS: DHK combined with metformin significantly reversed the prolongation of latency times of flash electroretinogram (FERG) and oscillatory potentials (OPs) in diabetic rats. Furthermore, DHK alone or combined with metformin showed a remarkable suppression of retinal neovascularization and amelioration of retinal internal limiting membrane morphology. Moreover, DHK alone or plus metformin reduced FBG (P<0.05), HbA1c 1094 (P<0.01) and MDA (P<0.01) levels in diabetic rats. In addition, reductions in levels of triglycerides (TG) (P<0.01) and low density lipoprotein cholesterol (LDL-c) (P<0.01 and P<0.05, respectively) were also observed in diabetic rats treated with DHK alone or plus metformin. CONCLUSION: DHK in combination with metformin had a preventive and therapeutic effect on DR in type-2 diabetic rats, and the possible mechanisms may be alleviating hyperglycemia, reducing oxidative stress and improving lipid metabolism.

Hypothyroidism affects astrocyte and microglial morphology in type 2 diabetes

In the present study, we investigated the effects of hypothyroidism on the morphology of astrocytes and microglia in the hippocampus of Zucker diabetic fatty rats and Zucker lean control rats. To induce hypothyroidism, Zucker lean control and Zucker diabetic fatty rats at 7 weeks of age orally received the vehicle or methimazole, an anti-thyroid drug, treatment for 5 weeks and were sacrificed at 12 weeks of age in all groups for blood chemistry and immunohistochemical staining. In the me- thimazole-treated Zucker lean control and Zucker diabetic fatty rats, the serum circulating triiodo- thyronine （T3） and thyroxine （＇I＂4） levels were significantly decreased compared to levels observed in the vehicle-treated Zucker lean control or Zucker diabetic fatty rats. This reduction was more prominent in the methimazole-treated Zucker diabetic fatty group. Glial fibrillary acidic protein im- munoreactive astrocytes and ionized calcium-binding adapter molecule 1 （Iba-1）-immunoreactive microglia in the Zucker lean control and Zucker diabetic fatty group were diffusely detected in the hippocampal CA1 region and dentate gyrus. There were no significant differences in the glial fibril- lary acidic protein and Iba-1 immunoreactivity in the CA1 region and dentate gyrus between Zucker lean control and Zucker diabetic fatty groups. However, in the methimazole-treated Zucker lean control and Zucker diabetic fatty groups, the processes of glial fibrillary acidic protein immunoreac- tive astrocytes and Iba-1 immunoreactive microglia, were significantly decreased in both the CA1 region and dentate gyrus compared to that in the vehicle-treated Zucker lean control and Zucker diabetic fatty groups. These results suggest that diabetes has no effect on the morphology of as- trocytes and microglia and that hypothyroidism during the onset of diabetes prominently reduces the processes of astrocytes and microglia.

Histopathological changes in retinas and F-ERG features of streptozotocin-induced diabetic rats treated with ozone

AIM： To study the histopathological changes in the retina and flash electroretinogram （F-ERG） features of ozone-treated streptozotocin （STZ）-induced diabetic rats. METHODS： Seventy male Sprague Dawley rats were grouped as follows： blank group （GB, n=10）, model control group （GM, n=18）, ozone group （GOs, n=19）, and oxygen group （GO2, n=18）. The model was induced by single intraperitoneal injection of STZ. Ozone or oxygen enteroclysm was given twice per week for 4wk. F-ERG and histopathological examinations were performed one month after treatment. RESULTS： Under dark adaption, as compared to GB, the other groups each had differential decreases in the a-wave amplitudes （P〈0.05）; the latencies were delayed in GM, GO2, and GO3 rats （P〈0.05）. Similar results were observed under light adaption, with the exception that the a-wave of the amplitudes （F=0.28, P〉0.05）. There were significant differences in the apoptosis index among the groups （P〈0.05）. Under ozone treatment, apoptosis was decreased in GO3 as compared to GM and GO2 . CONCLUSION： Ozone administration alleviates nerve damage and reduces pathology and apoptosis in the retinas of diabetic rats.

Protective effect of LIF-huM SCs on the retina of diabetic model rats

AIM:To investigate the protective effect of human umbilical cord mesenchymal stem cells(hUCMSCs)modified by the LIF gene on the retinal function of diabetic model rats and preliminarily explore the possible mechanism.METHODS:A stably transfected cell line of hUCMSCs overexpressing leukemia inhibitory factor(LIF)was constructed.Overexpression was verified by fluorescent quantitative polymerase chain reaction(qPCR).Forty-eight adult Sprague-Dawley rats were randomly divided into a normal control group(group A),streptozotocin-induced diabetic control group(group B),diabetic rats at 3mo injected with empty vector-transfected hUCMSCs(group C)or injected with LIF-hUCMSCs(group D).Four weeks after the intravitreal injection,analyses in all groups included retinal function using flash electroretinogram(F-ERG),retinal blood vessel examination of retinal flat mounts perfused with fluorescein isothiocyanate-dextran(FITCdextran),and retinal structure examination of sections using hematoxylin and eosin staining.Expression levels of adiponectin(APN),high-sensitivity C-reactive protein(hsCRP),and neurotrophin-4(NT-4)in each group was detected using immunohistochemistry,PCR,Western blotting,and ELISA,respectively.RESULTS:A stable transgenic cell line of LIF-hUCMSCs was constructed.F-ERG and FITC-dextran examinations revealed no abnormalities of retinal structure and function in group A,severe damage of the retinal blood vessels and function in group B,and improved retinal structure and function in group C and especially group D.qPCR,ELISA,and Western blot analyses revealed progressively higher APN and NT-4 expression levels in groups B,C,and D than in group A.hs-CRP expression was significantly higher in group B than in groups A,C,and D,and was significantly higher in group C than in group D(P<0.05).CONCLUSION:LIF-hUCMSCs protect the retina of diabetic rats by upregulating APN and NT-4 expression and downregulating hs-CRP expression in the retina.

Effects of a flavonoid-enriched orange peel extract against type 2 diabetes in the obese ZDF rat model

Effects of an enriched orange peel extract(OPE)against type 2 diabetes(T2D)were analyzed in ZDF rats which were hyperglycemic,dyslipidemic and express pro-inflammatory markers.Glucose related parameters were lowered in the lean control and metformin group as compared to ZDF vehicle controls.OPE was well tolerated and induced a decline in fasted blood glucose and increase levels of fed glucose although to a lesser degree as compared to metformin.However,OPE did not improve glucose tolerance but showed significantly elevated glucose levels.Furthermore,OPE treatment caused an increase of free fatty acids in a dose-responsive manner as well as elevated levels of cholesterol and LDL.The analysis of inflammatory mediators revealed a significant down-regulation of COX-2,ICAM-1,and TNF-˛in epididymal adipose tissue in response to OPE to a higher degree as compared to ibuprofen.In whole blood,IL-4 was upregulated in a dose-responsive manner as measured by ELISA.In summary,lipophilic OPE showed strong anti-inflammatory effects in adipose tissue,ambivalent effects against hyperglycemia,whereas hyperlipidemia was increased.Our study emphasize the complexity of anti-diabetic regimen suggesting a treatment with OPE to reduce inflammation in adipose tissue in combination with antidiabetic therapeutics as promising strategy against T2D.

N-acetylcysteine attenuates ischemia/reperfusion-induced cardiocyte apoptosis in diabetic rats

Objective：To study the effects of N-acetylcysteine （NAC） on ischemia/ reperfusion （I/R）-induced myocyte apoptosis in diabetic rats. Methods：The I/R heart model was made by ligation of the left anterior descending coronary artery （LAD） close to its origin. The LAD was occluded for 30 min followed by removal of ligation to allow subsequent reperfusion for 3 h. 72 rats were randomly divided into two groups , non-diabetic group （C, n = 36） and diabetic group ,（D, n = 36）. The animals in C group were randomly reassigned into sham-operated group （CS, n = 12） , I/R group （C I/R, n = 12） and treated with NAC group （CN, n = 12）. The rats in D group were also reassigned to sham-operated group （DS, n = 12） , I/R group （DI/R, n = 12） and treated with NAC group （DN, n = 12）. Malondialdehyde （MDA） and creatine kinase isoenzyme-MB （CK-MB） were measured. Infarct size（IS/AAR%）, the apoptosis index（AI） by TUNEL staining, the number of the cells positive for Caspase-3 and positive expression index （PEI） were calculated. Results：After I/R, the IS/AAR%, CK-MB, MDA, AI and Caspase-3 PEI were higher in diabetic group than those in non-diabetic group. Treatment with NAC decreased the above parameters in both non-diabetic and diabetic rats, but the parameters in diabetic rats were higher than those in non-diabetic rats. Conclusion：Diabetic rat hearts are more susceptible to I/R-induced myocardial necrosis and myocyte apoptosis. NAC can decrease the infarct size and attenuate cardiomyocyte apoptosis in both non-diabetic and diabetic rats, but the therapeutic effects are less effective in diabetic rats than those in non-diabetic rats.

Ocular findings in Zucker Diabetic Fatty rats emphasize the key role of neuroglia degeneration in diabetic retinopathy pathophysiology

Diabetes mellitus is a leading cause of acquired vision loss and one of the world＇s fastest growing chronic diseases. Diabetic retinopathy （DR）, a specific complication of chronic hyperglycemia, is the leading cause of acquired vision loss worldwide in middle-aged and there- fore economically active people that also increases the medical and economic burden on the society （Klein, 2007）.

Changes in 5α-reductase (type 2) gene expression in epididymis of puberty diabetic rats

The changes in 5α-reductase (type 2 ) gene expression in the epi-didymis of puberty diabetic rats were studied by the Northern blot and Dotblot method. Rats were divided into 3 groups: the control group (C), thediabetic group (D), and the diabetic group with insulin treatment (DI).Results: The Northern blot intensity of the caput epididymis in Group D is

Phenotypic Modulation of Mesangial Cells in Diabetic Rats and Effect of Tujian Mixture (菟箭合剂) on It

Objective: To explore whether there is phenotypic modulation of mesangial cells in streptozotocin (STZ) induced diabetic rats and study the effect of Tujian Mixture (TJM) on it. Methods: SD rats were divided into the normal control group , the unilateral nephrectomized control group , the STZ induced diabetes mellitus with unilateral nephrectomy model group , the Valsartan treated group (VT group, n=8) and the TJM treated group , rats in the latter two groups were modeled as in the DM group and treated with Valsartan (20 mg/kg·d) and TJM (20g/kg·d) respectively for 12 weeks. The expression of α-smooth muscle actin (α-SMA) and transforming growth factor-β 1 (TGF-β 1) in rats’ glomeruli were observed by immunohistochemistry assay, and the ratio of α-SMA and TGF-β 1 positive area/total glomerule tuft area (SMA/GT and TGF/GT) were analyzed using computer-assisted image analysis software. Results: In the NC and the QC groups, only trace of α-SMA positive staining was found. But there was prominant α-SMA positive staining in glomeruli of the DM group, with SMA/GT and TGF/GT increased significantly , and marked increase of 24 hrs proteinuria excretion ( P<0 01). As compared with the DM group, the three indexes were all significantly lower in the VT and ZY groups , and the lowering of proteinuria was more significant in the ZY group than that in the VT group (P<0 01). Conclusion: The expression of α-SMA in glomeruli in STZ induced diabetic rats with unilateral nephrectomy is pronounced, indicating that phenotypic modulation of mesangial cells involvement in the pathogenesis of diabetic nephropathy. TJM and Valsartan can reduce 24 hrs proteinuria excretion, inhibit the phenotypic modulation of mesangial cells and the expression of TGF-β 1 in glomeruli of diabetic rats, and the effect of TJM is more potent than that of Valsartan in lowering urinary protein excretion..

Expression of ceramide galactosy transferase in sciatic nerve of rats with diabetic peripheral neuropathy after electroacupuncture at Zusanli and Shenshu points

BACKGROUND： Ceramide galactosyltransferase （CGT） protein and mRNA expression defect can cause the abnormal morphology and slowing conduction velocity of peripheral nerve. Morphologic change and functional disorder of myelin sheath and axon appear when diabetic peripheral neuropathy （DPN） occurs. Whether electroacupuncture at Zusanfi（ST 36） and Shenshu（BL 32） points can enhance the expression of CGT protein and mRNA in the DPN tissue？ OBJECTIVE： To observe the effect of electroacupuncture at Zusanfi and Shenshu points on motor, sensory conduction velocity and CGT mRNA and its protein expression of sciatic nerve in rats with DPN. DESIGN： A randomized and controlled animal experiment SETTING ： Department of Neurology and Central Laboratory, Yueyang Hospital of Traditional Chinese ＆ Western Medicine, Shanghai University of Traditional Chinese Medicine. MATERIALS ： Totally 60 healthy male Wistar rats of clean grade, aged 4 month, with body mass of 200 to 220 g, were enrolled in this study. Streptozotocin （STZ, Sigma Company of USA, Batch No. S-0130）. METHODS： This study was carried out in the Animal Experimental Center and Central Laboratory, Yueyang Hospital of Traditional Chinese ＆ Western Medicine during February 2005 to March 2006. （1） Fifteen rats were randomly chosen,serving as normal group.AU the other rats were intraperitoneally injected once with STZ to develop experimental diabetic rat models. If fasting blood glucose was ≥ 15 mmol/L,sensory nerve and motor nerve conduction velocity of sciatic nerve was obviously slowed, tail-swaying temperature threshold was increased and myelinated nerve fiber of sciatic nerve changed, DPN models were successful. The successful model rats were randomly assigned into 3 groups： model group, control group（electroacupuncture at non-meridian-non-acupoint）and electroacupuncture group [electroacupuncture at Zusan/i and Shenshu points], with 15 rats each. The rats in the normal group and model group were untouched. In the electroacupuncture group （electroacupuncture at Zusanfi and Shenshu points）, Shenshu point （double） and Zusanfi point （double） were chosen referencing to The Atlas of the Rat＇s Acupoints. G6805- Ⅱ electric acupuncture apparatus was used, and current intensity was controlled at 20 min/time, once every other day, 12 times within 24 days. In the control group, the tip of rat-tail was stimulated, and the concrete procedures were the same as in the electroacupuncture at Zusanfi and Shenshu points. （2） Motor nerve conduction velocity and sensory nerve conduction velocity of rats were detected with neuroelectrophysiology detector in the end of the treatment, and the expressions of CGT protein and mRNA of sciatic nerve were detected with immunohistochemical method and fluorescent quantitative PCR technique. MAIN OUTCOME MEASURES： （1） Motor and sensory nerve conduction velocity. （2） The expression of CGT protein and its mRNA. RESULTS： All the 60 rats entered the stage of result analysis. （1） Comparison of motor and sensory nerve conduction velocity of rats after electroacupuncture： Motor nerve conduction velocity of rats in the model group[（31.37±3.69） m/s], control group [（32.74±5.42） m/s] and electroacupuncture group [（41.30 ±1.15） m/s] was significantly lower than that in the normal group [（41.30±1.15） m/s, P 〈 0.01]; The sensory nerve conduction velocity of rats in the model group[（18.17±9.54） m/s], control group [（21.39±5.61） m/s]and electroacupuncture group [（35.81 ±4.59） m/s] was significantly lower than that in the normal group [（46.38± 6.32） m/s,P 〈 0.01]; The motor and sensory nerve conduction velocity of electroacupuncture group was significantly higher than that in the model group [（38.04±2.01） m/s vs. （32.74±5.42） m/s,（35.81±4.59） m/s vs. （21.39±5.61） m/s,P 〈 0.01]. （2） Comparison of the expression of CGT protein of sciatic nerve of rats： The number of CGT positive cells of sciatic nerve in model group, control group or electroacupuncture group was significantly smaller than that in normal group [（9 770.33±1 461.73）, （10 588.13±1119.52）, （27 518.27± 9 078.29）, （37 769.67±4 021.81）/μm^2,P 〈 0.01]; The number of CGT positive cells of the sciatic nerve in the electroacupuncture group was significantly larger than that in the model group and control group （P 〈 0.01）. The number of CGT positive cells of sciatic nerve was close between control group and electroacupuncture group （P 〉 0.05）. （3） Comparison of CGT mRNA expression of sciatic nerve of rats： Ct value of CGT mRNA of sciatic nerve of rats in the model group,control group and electroacupuncture group was significantly higher than that in the normal group （13.75±2.60,14.81±2.80,11.67±1.75,9.30±0.98, P 〈 0.01 ）; Ct value of CGT mRNA of sciatic nerve of rats in the electroacupuncture group was significantly lower than that in the model group and control group （P 〈 0.01）, and that was close between electroacupuncture group and control group （P 〉 0.05）. CONCLUSION ： Electroacupuncture at Zusanfi and Shenshu points can increase motor and sensory nerve conduction velocity of rats with DPN. It might be associated with up-regulating the expression of CGT mRNA and its protein.

Polysaccharides from Huidouba and Its Effect on Type-2 Diabetes Mellitus

To evaluate the extraction process of Huidouba polysaccharides（ HDBP） and its anti-diabetic activity,this study focused on the two contents as follows：extraction process of HDBP,which was optimized by orthogonal experiments using the extraction ratio of HDBP for the index; and bioactivity evaluation of HDBP on streptozotocin-induced diabetic rat model based on the histological,biochemical and enzyme linked immunosorbent assay（ ELISA） method for histological observation,physiological and biochemical index such as fasting blood glucose（ FBG）,nitric oxide（ NO）,malondialdehyde（ MDA）,super oxide dismutase（ SOD） and insulin level detection in pancreas tissue respectively. The results showed that HDBP extraction ratio was the highest under following conditions： the extraction temperature at 90 ℃,the extraction time of 1. 5 h,and the solid-liquid ratio at 1： 10. Compared with the normal control group and the model group,histological observation,physiological and biochemical index and insulin level in pancreas tissue significantly increased and FBG significantly decreased according to the dosage administrated. HDBP affected Streptozotocin-induced diabetic rats.

1,25-Dihydroxyvitamin D_(3) effects on the regulation of the insulin receptor gene in the hind limb muscle and heart of streptozotocin-induced diabetic rats

In the present study, we examine the effects of the treatment with 1,25-dihydroxyvitamin D3 [150 IU/Kg (3.75 μg/Kg) once a day, for 15 days] to non-diabetic and streptozotocin-induced diabetic rats. The results indicate that treatment with 1,25-dihydroxyvitamin D3 had minor effects in non-diabetic rats. The same treatment in streptozotocin-induced diabetic rats, although it did not correct the hyperglycemia and hypoinsulinemia induced by the diabetes, caused other actions that could mean beneficial effects on the amelioration of diabetes e.g., it avoided body weight loss, increased calcium and phosphorus plasma levels, and corrected the over-expression of the insulin receptor mRNA species of 9.5 and 7.5 Kb present in the hind limb muscle and heart of these animals. These genomic 1,25-dihydroxyvitamin D3 effects could involve transcriptional mechanisms of repression mediated by vitamin D response elements in the rat insulin receptor gene promoter. Using computer analysis of this promoter, we propose the -249/-235 bp VDRE (5’GGGTGACCCGGGGTT3’) with a pyrimidine (T) in the (+7) position of the3’half-site as the best candidate for negative control by 1,25-dihydroxy-vitamin D3. In addition, posttranscriptional mechanisms of regulation could also be implicated. Thus, computer inspection of the5’untranslated region of the rat insulin receptor pre-mRNA indicated the presence of a virtual internal ribosome entry segment whereas the computer inspection of the3’untranslated region localized various destabilizing sequences, including various AU-rich elements. We propose that through these virtual cis-regulatory sequences, 1,25-dihydroxyvitamin D3 could control the translation and stability of insulin receptor mRNA species in the hind limb muscle and heart of diabetic rats.

Down-regulation of histone deacetylase 7 reduces biological activities of retinal microvascular endothelial cells under high glucose condition and related mechanism

AIM:To investigate the expression and effect of histone deacetylase 7(HDAC7)in human retinal microvascular endothelial cells(HRMECs)under high glucose condition and related mechanism,and the expression of HDAC7 in the retinal tissue in diabetic rats.METHODS:The expression of HDAC7 in HRMECs under high glucose and the retinal tissue from normal or diabetic rats were detected with immunohistochemistry and Western blot.LV-shHDAC7 HRMECs were used to study the effect of HDAC7 on cell activities.Cell count kit-8(CCK-8),5-ethynyl2’-deoxyuridine(EdU),flow cytometry,scratch test,Transwell test and tube formation assay were used to examine the ability of cell proliferation,migration,and angiogenesis.Finally,a preliminary exploration of its mechanism was performed by Western blot.RESULTS:The expression of HDAC7 was both upregulated in retinal tissues of diabetic rats and high glucosetreated HRMECs.Down-regulation of HDAC7 expression significantly reduced the ability of proliferation,migration,and tube formation,and reversed the high glucose-induced high expression of CDK1/Cyclin B1 and vascular endothelial growth factor in high glucose-treated HRMECs.CONCLUSION:High glucose can up-regulate the expression of HDAC7 in HRMECs.Down-regulation of HDAC7 can inhibit HRMECs activities.HDAC7 is proposed to be involved in pathogenesis of diabetic retinopathy and a therapeutic target.

Prophylactic Pattern Scanning Laser Retinal Photocoagulation for Diabetic Retinopathy in Spontaneously Diabetic Torii Fatty Rats: Preliminary Experimental Results

Research Background and Purpose: The number of diabetic patients is rapidly increasing, making it crucial to find methods to prevent diabetic retinopathy (DR), a leading cause of blindness. We investigated the effects of prophylactic pattern scanning laser retinal photocoagulation on DR development in Spontaneously Diabetic Torii (SDT) fatty rats as a new prevention approach. Methods: Photocoagulation was applied to the right eyes of 8-week-old Spontaneously Diabetic Torii (SDT) fatty rats, with the left eyes serving as untreated controls. Electroretinography at 9 and 39 weeks of age and pathological examinations, including immunohistochemistry for vascular endothelial growth factor and glial fibrillary acidic protein at 24 and 40 weeks of age, were performed on both eyes. Results: There were no significant differences in amplitude and prolongation of the OP waves between the right and left eyes in SDT fatty rats at 39 weeks of age. Similarly, no significant differences in pathology and immunohistochemistry were observed between the right and left eyes in SDT fatty rats at 24 and 40 weeks of age. Conclusion: Prophylactic pattern scanning retinal laser photocoagulation did not affect the development of diabetic retinopathy in SDT fatty rats.

Is Iba-1 protein expression a sensitive marker for microglia activation in experimental diabetic retinopathy?

AIM:To investigate the changes of Iba-1 and other potential markers for microglia activation in experimental diabetic retinopathy(DR).METHODS:Male Sprague-Dawley rats were rendered diabetes via intraperitoneal injection of streptozotocin.The retinas were harvested at 1 to 24 wk after diabetes onset.Hypoxia-treated mouse microglial cell line(BV2 cells)was employed as the in vitro model to mimic diabetic condition.The expressions of Iba-1,CD11 b,ICAM-1 as well as the inflammatory factors were examined with real-time polymerase chain reaction,Western blot and immunofluorescence both in vivo and in vitro.RESULTS:Compared with age-matched normal control,the number of microglia(Iba-1 positive immunostaining)in diabetic rat retinas was increased from 1 to 24 wk of diabetes,which was most obvious at 12 wk of diabetes.Iba-1 protein expression detected by Western blot was increased slightly in diabetic rat retinas compared with that in age-matched normal control;however,there was statistically significant between two groups only at 2 wk after diabetes onset.The m RNA expression of Iba-1 was decreased significantly at 2 and 4 wk of diabetic rat retinas,and remained unchanged at 8 and 12 wk of diabetes.In BV2 cells,there was no significant change for the Iba-1 protein expression between normoxia and hypoxia groups;however,its m RNA level was decreased significantly under hypoxia.To further characterize microglial activation,F4/80,CD11 b and inflammatory factors were detected both in vivo and in vitro.Compared with normal control,the expressions of F4/80 and CD11 b as well as the inflammatory factors,such as ICAM-1,i NOS,COX2,IL-1βand IL-6,were increased significantly both in vivo and in vitro.CONCLUSION:Iba-1 protein expression might not be a sensitive marker to evaluate the activation of microglia in experimental DR.However,Iba-1 immunostaining,in combination with other markers like CD11 b and ICAM-1,could be well reflect the activation of microglia.Thus,it is of great importance to explore other potential marker to evaluate the activation of microglia.