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.

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.

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.

Effect of Tangweian Jianji on upper gastrointestinal remodeling in streptozotocin-induced diabetic rats

AIM： To investigate the effect of Tangweian Jianji （TWAJJ） on the biomechanical and morphometrical remodeling of the upper gastrointestinal tract in diabetic rats. METHODS： Diabetes was induced in 27 rats by in- jecting streptozotocin （40 mg/kg body weight）, the animals were then divided into three groups （n = 9 in each group）, i.e., diabetic control （DM）; high dose （10 g/kg, T1） and low dose （5 g/kg, T2）. Another 10 rats acted as normal controls （Control）. TWAJJ was admin- istered by gavage once daily. Blood glucose and serum insulin levels were measured. Circumferential length, wall thickness and opening angle were measured from esophageal, duodenal, jejunal and ileal ring segments. The residual strain was calculated from the morpho- metric data. Step-wise distension was carried out on esophageal and jejunal segments. The obtained data on the length, diameter and pressure changes were then used to calculate the circumferential and longitu- dinal stresses and strains. Real-time reverse transcrip- tion polymerase chain reaction was used to detect the receptor of advanced glycation end-products （RAGE） mRNA level in jejunal tissues. RESULTS： At the end of the experiment, the blood glucose level was significantly higher and the serum insulin level was significantly lower in DM, T1 and T2 groups than in the control group （Glucose： 30.23 ± 0.41 mmol/L, 27.48 ± 0.27 mmol/L and 27.84 ± 0.29 mmol/ L vs 5.05 ± 0.04 mmol/L, P = 1.65 x 10-16, P = 5.89 x 1019 and P = 1.63 x 10-Is, respectively; Insulin： 1.47 ± 0.32 °tg/L, 2.66 ± 0.44 pg/L, 2.03 ± 0.29 pg/L and 4.17 ± 0.54 pg/L, P = 0.0001, P = 0.029 and P = 0.025, re- spectively）. However, these levels did not differ among the DM, T1 and T2 groups. The wet weight per unit length, wall thickness and opening angle of esophageal and intestinal segments in the DM group were signifi- cantly higher than those in the control group （from P = 0.009 to P = 0.004）. These parameters in the T1 group were significantly lower than those in the DM group （wet weight, duodenum： 0.147 ± 0.003 g/cm vs 0.158 ± 0.001 g/cm, P = 0.047; jejunum, 0.127 ± 0.003 g/cm vs 0.151：1：0.002 g/cm, P = 0.017; ileum, 0.127 ± 0.004 g/cm vs 0.139 ± 0.003 g/cm, P = 0.046; wall thickness, esophagus： 0.84±0.03 mm vs 0.94 ± 0.02 ram, P = 0.014; duodenum： 1.27 ± 0.06 mm vs 1.39 ± 0.05 ram, P = 0.031; jejunum： 1.19 ± 0.07 mm vs 1.34 ± 0.04 mm, P = 0.047; ileum： 1.09 ± 0.04 mm vs 1.15 ± 0.03 mm, P = 0.049; opening angle, esophagus： 112.2 ± 13.2° vs 134.7 ± 14.7°, P = 0.027; duodenum： 105.9 ± 12.3° vs 123.1 ± 13.1°, P = 0.046; jejunum： 90.1 ± 15.4° vs 115.5 ± 13.3°, P = 0.044; ileum： 112.9 ± 13.4° vs 136.1 ± 17.1°, P = 0.035）. In the esophageal and jejunal segments, the inner residual stain was significantly smaller and the outer residual strain was larger in the DN group than in the control group （P = 0.022 and P = 0.035）. T1 treatment significantly restored this biomechanical alteration （P = 0.011 and P = 0.019）, but T2 treatment did not. Fur- thermore, the circumferential and longitudinal stiffness of the esophageal and jejunal wall increased in the DM group compared with those in the control group. T1, but not T2 treatment, significantly decreased the cir- cumferential wall stiffness in the jejunal segment （P = 0.012） and longitudinal wall stiffness in the esophageal segment （P = 0.023）. The mRNA level of RAGE was significantly decreased in the T1 group compared to that in the DN group （P = 0.0069）. CONCLUSION： TWAJJ （high dose） treatment partly restored the morphometric and biomechanical remodel- ing of the upper gastrointestinal tract in diabetic rats.

Hypoglycaemic effect of Berberis vulgaris L.in normal and streptozotocin-induced diabetic rats

Objective:To achieve a primary pharmacological screening contained in the aqueous extract of Berberis vulgaris(B.vulgaris) and to examine the hypoglycaemic effect and biochemical parameters of aqueous and saponins extract on groups of rats rendered diabetic by injection of streptozotocin.Methods:The phytochemicol tests to detect the presence of different compounds were based on the visual observation of color change or formation of precipitate after the addition of specific reagents.Diabetes was induced in rats by intraperitoneal(i.p.) injection of streptozotocin(STZ) at a dose of 65 mg/kg bw.The fasting blood glucose levels were estimated by glucose oxidase-peroxidase reactive strips(Dextrostix,Bayer Diagnostics).Blood samples were taken by cutting the tip of the tail.Serum cholesterol and serum triglycerides were estimated by enzymatic DHBS colorimetric method.Results:Administration of 62.5 and 2S.0 mg/kg of saponins and aqueous extract respectively in normal rats group shows a significant hypoglycemic activity(32.33%and 40.17%respectively) during the first week.However,diabetic group treated with saponin extract produced a maximum fall of 73.1%and 76.03%at day 1 and day 21 compared to the diabetics control.Also,blood glucose levels of the diabetic rats treated with aqueous extract showed decrease of 78.79%on the first day and the effect remains roughly constant during 3 week. Both extracts also declined significantly biochemical parameters(20.77%-49.00%).The control in the loss of body weight was observed in treated diabetic rats as compared to diabetic controls. Conclusions:These results demonstrated significant antidiabetic effects and showed that serum cholesterol and serum triglycerides levels were decreased,significantly,consequently this plant might be of value in diabetes treatment.

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.

Syringic acid improves oxidative stress and mitochondrial biogenesis in the liver of streptozotocin-induced diabetic rats

Objective:To determine the effects of syringic acid on hepatic damage in diabetic rats.Methods:Diabetes was induced by streptozotocin.Diabetic rats were given syringic acid at doses of 25,50 and 100 mg/kg by oral gavage for 6 weeks.Syringic acid effects on the liver were evaluated by examination of plasma biochemical parameters,and pathological study.In addition,biomarkers of lipid peroxidation and antioxidant status of liver tissues were assessed.Real time-PCR was performed to investigate the m RNA expression levels of mitochondrial biogenesis indices in different groups.Results:Syringic acid significantly attenuated the increase in most of plasma biochemical parameters in diabetic rats.Moreover,syringic acid treatment increased the catalase activity while it reduced the superoxide dismutase activity and hepatic malondialdehyde level in diabetic rats.There was no difference between the glutathione content of the treated and untreated groups.These findings were supported by alleviation of histopathological damages in the syringic acid-treated groups compared to the untreated diabetic group.Syringic acid also significantly upregulated the hepatic m RNA expression of PGC-1α,NRF-1,and NRF-2 and increased the mtD NA/nD NA ratio in diabetic rats.Conclusions:Syringic acid can be considered as a suitable candidate against hepatic complications since it can reduce oxidative damages in diabetic cases.Furthermore,it has the potential of targeting hepatic mitochondria in diabetes.

Antidiabetic effect of Opuntia dillenii seed oil on streptozotocin-induced diabetic rats

Objective: To assess the antidiabetic effect of Opuntia dillenii seed oil on rats with diabetes mellitus. Methods: A rat diabetes model was established by intraperitoneal injection of rats with 50 mg/kg streptozotocin. Thirty albino Wistar rats were divided into five groups: the diabetic control group and normal control group were treated only with distilled water, two diabetic groups received 1 and 2 m L/kg of oil per day, respectively, for 30 days and one diabetic group received 2 mg/kg of glibenclamide. In addition, blood glucose was determined weekly. Body weight, average daily food, water intake and urinary volume of each animal were determined before and after the treatment period. After the treatment period, hepatic glycogen was determined using the anthrone reagent, and glycosuria, total cholesterol, triglycerides, alanine aminotransferase, aspartate aminotransferase, urea, creatinine and uric acid were estimated using common clinical diagnostic kits. Results: Oral intake of the oil at 1 and 2 m L/kg for the diabetic animals significantly diminished blood glucose, glycosuria, total cholesterol, triglycerides, alanine aminotransferase, aspartate aminotransferase, urea, creatinine and uric acid, accompanied by a noticeable elevation in the amount of hepatic glycogen in comparison with the diabetic control group. Similarly, Opuntia dillenii seed oil significantly increased the food intake and decreased the urinary volume per day in treated rats of the same groups in comparison with the period before the treatment intervention and attenuated body weight loss in the diabetic rats. Moreover, this effect of the oil was dose dependent. On the other hand, the oil did not affect their need for water. Conclusions: The results show that Opuntia dillenii seed oil has a very important antidiabetic effect on streptozotocin-induced diabetic rats. Hence, we suggest it as a preventive control of diabetes mellitus.

Effect of insulin in combination with selenium on blood glucose and GLUT4 expression in skeletal muscle of streptozotocin-induced diabetic rats

Objective To evaluate the effect of low-dose insulin [1 U/(kg·d)] in combination with selenium [180 g/(kg·d)] on general physiological parameters and glucose transporter (GLUT4) level in skeletal muscle of streptozotocin (STZ)-induced diabetic rats. Methods Diabetic rats were treated with insulin,selenium,and insulin and selenium in combination for four weeks. The level of blood glucose was determined using One Touch SureStep Blood Glucose meter and the level of GLUT4 in skeletal muscle was examined by immunoblotting and immunohistochemistry. Results Our data showed that insulin in combination with selenium could significantly lower blood glucose level and restore the disturbance in GLUT4 level in skeletal muscle. Treatment with insulin was only partially effective in restoring diabetic alterations. Conclusion It can be concluded that there is a synergistic action between insulin and selenium,and that treatment of diabetic rats with combined doses of insulin and selenium is effective in the normalization of blood glucose level and correction of altered GLUT4 distribution in skeletal muscle of diabetic rats.

Hypoglycemic and anti-hyperglycemic study of Ocimum tenuiflorum L.leaves extract in normal and streptozotocin-induced diabetic rats

Objective:To investigate the antidiabetic activity of Ocimum tenuiflorum L.(O.tenuiflorum) leaves used in the traditional medicine management of diabetes in Malaysia.Methods:O.tenuiflorum leaves were extracted sequentially with hexane,chloroform,ethyl acetate,methanol,and water.The extracts were evaluated in terms of antidiabetic activity by using acute,subcutaneous glucose tolerance,and sub-chronic tests in streptozotocininduced diabetic rats.The extracts were also subjected to phytochemical analyses.Results:With an acute dose(1 g/kg),the methanol extracts showed significant reduction(31%) in fasting blood glucose(FBG) of the streptozotocin-induced diabetic rats.The FBG-decreasing effect of ethyl acetate extract was more rapid than that of the other extracts;the decreasing rates were 20%after 2 h,21%after 3 h,and 8%after 5 and 7 h.After 7 h(31%),the effect of methanol extract on FBG was significantly lower than that of metformin.In the subcutaneous glucose tolerance test,only methanol and hexane extracts showed the similarity of metformin in diabetic rats.After 14 days,the effects of these extracts were similar to those of metformin(63.33%).The total flavonoid and phenolic contents of extracts decreased as the polarity of the extraction solvent increased.Conclusions:The results obtained provide support for a possible use of O.tenuiflorum leaves in managing hyperglycemia and preventing the complications associated with it in type 2 diabetic.

Long-term effects of Nigella sativa L. oil on some physiological parameters in normal and streptozotocin-induced diabetic rats

The long-term effects of Nigella sativa L. oil on some physiological parameters were investigated in normal and streptozotocin (STZ)-induced diabetic male Wistar rats. STZ-induced diabetic rats showed significant increases in the levels of blood glucose, triglycerides, cholesterol, low density lipoprotein (LDL-cholesterol), uric acid, urea, creatinine, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) while high density lipoprotein (HDL-cholesterol) and total protein levels were significantly decreased compared to normal rats. Administration of black seed oil to diabetic rats resulted in a significant decrease in blood glucose, triglycerides, cholesterol, LDL–cholesterol ALT, AST and uric acid while HDL–cholesterol level was markedly increased compared to untreated diabetic rats after seven weeks of treatment. The results of this study indicate that the diet containing the oil of N. sativa improves the examined physiological parameters in STZ-induced diabetic rats especially when it is used for a longer period.

Garlic (<i>allium sativum</i>) modulates the expression of angiotensin II AT₂receptor in adrenal and renal tissues of streptozotocin-induced diabetic rats

The loss of balance between the antagonistic activities of angiotensin II AT1/AT2 receptors has been impli-cated as a major mediator in the development of hypertension and progressive nephropathy in expe-rimental diabetes. The present study was designed to investigate the potential of garlic to modulate the level of expression of the AT2 receptor in the adrenal and renal tissues of diabetic rats. Three groups of rats were studied after 8 weeks following diabetes induction: normal, streptozotocin-induced diabetic (control diabetic), and garlic-treated diabetic rats. A polyclonal antibody of proven specificity to the AT2 receptor, as verified by Western blotting and emplo- yed in immunohistochemical assays, indicated that compared to normal rats, the highest adrenocortical AT2 receptor expression was significantly shifted from the zona glomerulosa to the zona fasciculate/ reticularis, and was significantly reduced in adrenomedul- lary chromaffin cells of control diabetic rats. In the kidney, STZ treatments were associated with a signi- ficant decrease in AT2 receptor expression throughout glomeruli and all cortical and medullary tubular segments. Compared to control diabetic rats, the labeling of the AT2 receptor in the garlic-treated diabetic group was restored among adrenocortical zona glomerulosa cells and adrenomedullary chromaffin cells and significantly reduced in the zona fasiculata, and was also restored in glomeruli and throughout renal cortical and medullary tubular segments, to le- vels comparable to those observed in normal rats. The capacity of garlic to modulate diabetes-induced AT2 receptor down-regulation may be implicated in restoring the recuperative processes mediated by AT2 receptors, which interfere with the development of hypertension and nephropathy.

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.

Antidiabetic and haematological effect of aqueous extract of stem bark of Afzelia africana(Smith) on streptozotocin-induced diabetic Wistar rats

Objective:To investigate the antidiabetic properties of aqueous extract of stem bark of Afzelia africana(A.africana)and its beneficial effect on haematological parameters in streptozotocin induced diabetic rats.Methods:A total of 30 rats including 24 diabetic and 6 normal rats were used for this study.Diabetes was induced in male Wistar rats by intraperitoneal injection of streptozotocin.After being confirmed diabetic,animals were orally treated with distilled water or extracts at 100 or 200 mg/kg body weight daily for 10 days.The haematological parameters including red blood and white blood cells and their functional indices were evaluated in diabetic treated groups compared with the controls.Results:The extract significantly reduced the blood glucose levels while the best result was obtained at 200 mg/kg body weight The feed and water intake in diabetic rats were significantly reduced while weight loss was minimized at both dosages.Similarly,the levels of red blood,white blood cells and their functional indices were significantly improved after extract administration at both doses.Conclusions:It can be concluded that the aqueous extract of bark of A.africana possesses antihyperglycemic properties.In addition,the extract can prevent various complications of diabetes and improve some haematological parameters.Further experimental investigation is needed to exploit its relevant therapeutic effect to substantiate its ethnomedicinal usage.

Modulation of antioxidant status in streptozotocin-induced diabetic male wistar rats following intake of red palm oil and/or rooibos

Objective:To investigate the role of red palm oil(RPO),rooibos tea extract(RTE)and their combined treatment(RPO+RTE)on antioxidant status in streptozotocin(STZ)-induced diabetic rats.Methods:Diabetes mellitus was induced by a single administration of streptozotocin(50 mg/kg)and the rats were treated for 7 weeks.Antioxidant enzymes[calalase(CAT),glutathione peroxidase(GPx),superoxide dismutase(SOD)],antioxidant capacity[trolox equivalence antioxidant capacity(TEAC),oxygen radical absorbance capacity(ORAC)]as well as total protein,albumin,globulin,total glutathione,conjugated diene and thiobarbituric acid reactive substances(TBARS)were investigated.Results:Treatment with RPO,RTE and RPO+RTE significantly(p>0.05)improved liver SOD and plasma ORAC in the diabetic rats.Similarly,diabetic rats treated with RTE and RPO+RTE enhanced liver GPx.A significant(P<0.05)increase in the plasma TBARS in the diabetic control group was observed when compared with the normal control group.Treatment of diabetic rats with RTE and RPO+RTE reduced plasma TBARS to a level not significantly different at P<0.05 from the normal control group.Conclusions:The results revealed the anti-oxidative potentials of red palm oil,rooibos and their combination in diabetic conditions and hence,they could be useful in the management of diabetes and its complications.

Changes in expression of adrenomedullin in the myocardium of streptozotocin-induced diabetic rats

Background Adrenomedullin is a potent vasodilating peptide and involved in many cardiovascular diseases. However, whether adrenomedullin is involved in the pathogenesis of diabetic cardiomyopathy is still unknown. Our aim was to characterize the expression pattern of adrenomedullin in the myocardium of streptozotocin-induced diabetic rats. Methods The weight, blood glucose, and urine glucose of 20 streptozotocin-induced diabetic rats were measured before and after model induction in the diabetic and control groups. The alteration of the adrenomedullin expression was explored in the left ventricular myocardium in both groups by immunohistochemistry. Changes in heart ultrastructure were also analyzed by using hemotoxylin and eosin staining and transmission electron microscopy. All data were analyzed by the independent samples ttest. Results The data of weight, blood glucose, and urine glucose had no significant difference between the control and the diabetic groups before animal model induction. Four weeks after the induction of diabetes, the differences between the two groups in weight, blood glucose, and urine glucose were distinct. When compared with the control group, the diabetic group showed ultrastructural changes including hypertrophy, fibrosis, myofibrillar disarrangements, mitochondrial disruption, and increase in nuclear membrane invaginations. A significant decrease of adrenomedullin expression was also observed in cardiac myocytes of the diabetic rats （P〈0.01）. Conclusions Our study provides experimental evidence that hyperglycemia could damage cardiac myocytes. Down-regulation of cardioprotective peptide adrenomedullin in the myocardium of streptozotocin-induced diabetic rats may contribute to the diabetic cardiomyopathy and left ventricular dysfunction.

Dan Huang Ming Mu Recipe Suppresses the Progression of Streptozotocin-induced Diabetic Retinopathy After Retinal Laser Photocoagulation in Brown Norway Rats via Down-regulating Vascular Endothelial Growth Factor and Up-regulating Pigment Epithelium-derived

Objective To analyze the effects of Dan Huang Ming Mu Recipe(DHMMR)(a pharmaceutical preparation from herbs and having the function of replenishing vital essence,removing heat,promoting blood circulation and excreting pathogenic water) on diabetic retinopathy(DR) after retinal laser photocoagulation through regulating the expression of vascular endothelial growth factor(VEGF) and pigment epithelium-derived factor(PEDF).Methods Forty male Brown Norway(BN) rats were randomly divided into blank group(group A,10 BN rats) and model group(30 BN rats).DR models were induced by 40 mg/kg streptozotocin(STZ) and the body weight and blood glucose of rats were monitored.After 12-week injection,fluorescein fundus angiography(FFA) and histopathological examination were detected to confirm the successful establishment of DR models.Subsequently,the right eyes of model group rats were conducted retinal laser photocoagulation with the left eyes having no retinal laser photocoagulation and rats of the model group were randomly divided into group B(the model control group),group C(the positive control group),and group D(the DHMMR group),with 10 rats in each group.Rats of the group A and the group B were given vehicle,and the group C were given calcium dobesilate suspension by gavage,and the group D were given DHMMR by gavage.After 4-week gavage,FFA was carried out to observe the fundus microvascular change.Then,the rats were sacrificed to do histopathological examinations and the serum levels of P-selectin,cAMP,cGMP,and the relative expression of the protein of VEGF and PEDF in retina were detected.Results After 12-week STZ injection,the blood glucose of the model group were pronouncedly higher than the blank group(P < 0.01).Fundus micro-hemangioma changes were observed in the rats of the model group through FFA,and the rats of the blank group did not see any changes.The pictures of HE staining showed that the retinal structure of the model group was more disordered than the blank group.After 4-week gavage,treatments with DHMMR showed dramatic reduction of serum levels of Pselectin,cAMP and cGMP compared with the group B(P < 0.01).FFA and histopathological examinations of DHMMR-treated rats revealed significantly suppression of retinal edema,fundus microvascular destruction and retinal destruction distinguishing from the group B.And the relative expression of VEGF protein of the group D and the group A was markedly lower than that of the group B(P < 0.01).The relative expression of PEDF protein of the group D and the group A was dramatically higher than that of the group B to the contrary(P < 0.01).Conclusions DHMMR demonstrates pronounced suppressive effects on the progression of DR after retinal laser photocoagulation,through down-regulating VEGF and upregulating PEDF.

Evaluation of Anti-Hyperglycemic and Anti-Hyperlipidemic Activities of Water Kefir as Probiotic on Streptozotocin-Induced Diabetic Wistar Rats

Diabetes mellitus is a predominant chronic disease which causes mortality of millions of people yearly. Its prevalence is on the rise worldwide. Water kefir is fermented food produced by a matrix of polysaccharides containing bacteria and yeasts, with therapeutic properties. Our study aimed to evaluate anti-hyperglycemic and anti-hyperlipidemic activities of water kefir on streptozotocin-induced diabetic Wistar rats. Adult Wistar rats were made diabetic by intraperitoneal injection of streptozotocin, and were given or not kefir in drinking water for 5 weeks. Body weight, glucose and lipid levels were measured. The results demonstrated evident improvement in body weight, glucose, and lipid profiles of treated rats comparing with diabetic or control rats. Water kefir is found to be less cost hypoglycemic and hypolipidimic treatment and less time consuming. Water kefir can potentially be useful food for diabetes to control glucose and lipid levels.

Astragalin attenuates diabetic cataracts via inhibiting aldose reductase activity in rats

AIM:To investigate the aldose reductase(AR)inhibition capacity of astragalin(AST)against streptozoticin-induced diabetic cataracts(DCs)in rats.METHODS:Ex vivo investigations were conducted by treating the lens of a goat placed for 72h in artificial aqueous humor(AAH)of pH 7.8 at room temperature with cataract-causing substance(55 mmol/L of galactose)and in vivo studies were performed on rats via induction with streptozotocin.AST was administered at different dose levels and scrutinize for DC activity.RESULTS:In diabetic rats,AST improved the body weight,blood insulin,and glucose as well as the levels of galactitol in a dose-dependent way,other biochemical parameters i.e.inflammatory mediators and cytokines,and also suppress AR activity.The level of the antioxidant parameters such as superoxide dismutase(SOD),catalase(CAT),and glutathione(GSH)activity were also altered on a diabetic lens after the administration of the AST.CONCLUSION:AST protects against lens opacification to avoid cataracts and polyols formation,indicating that it could be used as a potential therapeutic agent for diabetes.

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.