Comparison of the effect of intravitreal bevacizumab and intravitreal fasudil on retinal VEGF,TNFα,and caspase 3 levels in an experimental diabetes model

AIM: To evaluate the influence of an intravitreal injection of bevacizumab and fasudil on the retinal vascular endothelial growth factor(VEGF),tumor necrosis factor alpha(TNFα),and caspase 3 levels in a diabetic rabbit model. · METHODS: The study included 6 healthy rabbits(Group 1),6 rabbits with experimentally induced diabetes mellitus(DM)(Group 2),7 rabbits with experimentally induced DM to which intravitreal bevacizumab was administered(Group 3),and 7 rabbits with experimentally induced DM to which intravitreal fasudil was administered(Group 4). An intravitreal injection of 1.25mg/50μL bevacizumab in the right eye of rabbits in Group 3 and an intravitreal injection of 0.0064mg/50μL fasudil in the right eye of rabbits in Group 4 were administered on day 21 after the induction of DM. The studied eyes of the rabbits were enucleated three days after the intravitreal injection. The TNFα,VEGF,and caspase 3 levels were determined using the ELISA method. · RESULTS: There was a statistically significant difference in the VEGF and caspase 3 levels between groups(P =0.005 and P =0.013,respectively),but the TNF α level did not differ significantly between groups(P = 0.792). It was found that VEGF levels were significantly lower in Group 1 and Group 3 than in Group 2 using the Mann-Whitney U test with the Bonferroni correction(P = 0.004 for both comparison). There was no statistically significant difference between other groups with regard to VEGF levels(the P value ranged between 0.015 and 0.886). Although the P values of the caspase 3 levels were 0.015 for Group 1 and Group 4,0.038 for Group 2and Group 3,and 0.018 for Group 3 and Group 4,these P values remained above the threshold P value of 0.0083,which was the statistically significant level for post hoc tests. ·CONCLUSION: An intravitreal injection of bevacizumab decreased both the VEGF level,which plays a role in angiogenesis,and the caspase 3 level,which plays a role in apoptosis. Although not as effective as bevacizumab,fasudil had a beneficial effect on the VEGF levels but significantly increased the caspase 3 levels.

Changes of activity of liver glycogen synthase in experimental diabetes mellitus rats

OBJECTIVE: To study the activity of liver glycogen synthase in analogous model of NIDDM rats. METHODS: Male Wistar rats were injected with low dose of streptozotocin (STZ) (30 mg/kg body weight) via tail vena and those animals with glucose tolerance impaired and level of insulin equal to or higher than that of the controls at 18th week were taken as the analogous rat model of NIDDM. The activity of liver glycogen synthase (GS) was assayed at the end of experiment. RESULTS: Type I-enzyme: 0.18 +/- 0.06 mumol/min.g versus 0.24 +/- 0.09 mumol/min.g, P

Insulin is necessary for the hypertrophic effect of cholecystokinin-octapeptide following acute necrotizing experimental pancreatitis

AIM:In previous experiments we have demonstrated that by administering low doses of cholecystokinin-octapeptide (CCK-8),the process of regeneration following L-arginine (Arg)-induced pancreatitis is accelerated.In rats that were also diabetic(induced by streptozotocin,STZ),pancreatic regeneration was not observed.The aim of this study was to deduce whether the administration of exogenous insulin could in fact restore the hypertrophic effect of CCK-8 in diabetic-pancreatitic rats. METHODS:Male Wistar rats were used for the experiments. Diabetes mellitus was induced by administering 60mg/kg body mass of STZ intraperitoneally(i.p.),then,on d 8, pancreatitis was induced by 200mg/100 g body mass Arg i.p.twice at an interval of 1 h.The animals were injected subcutaneously twice daily(at 7 a.m.and 7 p.m.)with 1 μg/kg of CCK-8 and/or 2 IU mixed insulin(300g/L short- action and 700g/L intermediate-action insulin) for 14 d after pancreatitis induction.Following this the animals were killed and the serum amylase,glucose and insulin levels as well as the plasma glucagon levels,the pancreatic mass/body mass ratio(pm/bm),the pancreatic contents of DNA,protein,amylase,lipase and trypsinogen were measured.Pancreatic tissue samples were examined by light microscopy on paraffin-embedded sections. RESULTS:In the diabetic-pancreatitic rats treatment with insulin and CCK-8 significantly elevated pw/bm and the pancreatic contents of protein,amylase and lipase vs the rats receiving only CCK-8 treatment.CCK-8 administered in combination with insulin also elevated the number of acinar cells with mitotic activities,whereas CCK-8 alone had no effect on laboratory parameters or the mitotic activities in diabetic-pancreatitic rats. CONCLUSION:Despite the hypertrophic effect of CCK-8 being absent following acute pancreatitis in diabetic-rats, the simultaneous administration of exogenous insulin restored this effect.Our results clearly demonstrate that insulin is necessary for the hypertrophic effect of low-doses of CCK-8 following acute pancreatitis.

Treatment with NADPH oxidase inhibitor apocynin alleviates diabetic neuropathic pain in rats

Increased reactive oxygen species by the activation of NADPH oxidase（NOX） contributes to the development of diabetic complications.Apocynin,a NOX inhibitor,increases sciatic nerve conductance and blood flow in diabetic rats.We investigated potential protective effect of apocynin in rat diabetic neuropathy and its precise mechanism of action at molecular level.Rat models of streptozotocin-induced diabetes were treated with apocynin（30 and 100 mg/kg per day,intragastrically） for 4 weeks.Mechanical hyperalgesia and allodynia were determined weekly using analgesimeter and dynamic plantar aesthesiometer.Western blot analysis and histochemistry/immunohistochemistry were performed in the lumbar spinal cord and sciatic nerve respectively.Streptozotocin injection reduced pain threshold in analgesimeter,but not in aesthesiometer.Apocynin treatment increased pain threshold dose-dependently.Western blot analysis showed an increase in catalase and NOX-p47 phox protein expression in the spinal cord.However,protein expressions of neuronal and inducible nitric oxide synthase（n NOS,i NOS）,superoxide dismutase,glutathion peroxidase,nitrotyrosine,tumor necrosis factor-α,interleukin-6,interleukin-1β,aldose reductase,cyclooxygenase-2 or MAC-1（marker for increased microgliosis） in the spinal cord remained unchanged.Western blot analysis results also demonstrated that apocynin decreased NOX-p47 phox expression at both doses and catalase expression at 100 mg/kg per day.Histochemistry of diabetic sciatic nerve revealed marked degeneration.n NOS and i NOS immunoreactivities were increased,while S-100 immunoreactivity（Schwann cell marker） was decreased in sciatic nerve.Apocynin treatment reversed these changes dose-dependently.In conclusion,decreased pain threshold of diabetic rats was accompanied by increased NOX and catalase expression in the spinal cord and increased degeneration in the sciatic nerve characterized by increased NOS expression and Schwann cell loss.Apocynin treatment attenuates neuropathic pain by decelerating the increased oxidative stress-mediated pathogenesis in diabetic rats.

Effects of Electroacupuncture at Weiwanxiashu and Zusanli Points on Blood Glucose and Plasma Pancreatic Glucagon Contents in Diabetic Rabbits

The Effects of electroacupuncture (EA) at Weiwanxiashu (EX-B3) and Zusanli (ST 36) points on blood glucose (BG) and plasma pancreatic glucagon (PG) contents were dynamically observed in diabetic rabbits induced by Alloxan. It is found that acupuncture at Weiwanxiashu point can significantly lower the BG content and inhibit release of PG; no significant changes in BG and PG are found when acupuncture is given at Zusanli (ST 36) point alone, however BG and PG contents decrease more obviously when acupuncture employed at both Zusanli and Weiwanxiashu, suggesting that Zusanli has a marked synergetic action with Weiwanxiashu.

Biomechanics of Bone in Experimental Diabetic rats.

The biomechanics of bone In diabetics and its response to insulin treatment was not clear.We investigated the impace of alloxan-induced diabetes and insulin treatment on the biomechanical characteristics of bones．Sprague-Dawley rats were divided into three groups:

Increased expression of neuropeptide Y and its mRNA in STZ-diabetic rats

OBJECTIVE: To study the relationship between neuropeptide Y (NPY) and diabetes by examining the content and distribution of NPY and its mRNA expression in the hypothalamus and pancreas of STZ-diabetic rats. METHODS: Thirty Wistar rats were randomly divided into 3 groups (diabetic group, diabetic insulin treatment group, and control group). After feeding for 24 weeks, the rats were sacrificed. The expression of NPY in the hypothalamus and pancreas was detected with immunohistochemistry and in situ hybridization. RESULTS: (1) The hypothalamic content of NPY and its mRNA were significantly increased in STZ-diabetic rats in comparison with normal controls. Increased expression of NPY mRNA was found only in the arcuate nucleus and not in the paraventricular nucleus in diabetic rats, suggesting that NPY was produced in the arcuate nucleus. (2) The hypothalamic content of NPY and its mRNA in STZ-diabetic rats were visibly reduced after insulin treatment compared with that in untreated diabetic rats. This supports the hypothesis that insulin deficiency in the brain may be responsible for increased hypothalamic NPY gene expression in diabetic rats. (3) The increase of hypothalamic NPY in STZ diabetic rats associated with hyperphagia and polydipsia could be reversed by insulin replacement, suggesting that increased hypothalamic NPY contributes to the pathophysiological progress of the diabetic state. (4) The present study demonstrated for the first time that the content of NPY and its mRNA in the pancreas was increased in STZ-diabetic rats, and that the distribution of NPY-positive cell in islets was changed from the periphery to the whole islet. The content and distribution of NPY and its mRNA in islets were not changed by insulin treatment. CONCLUSION: Increased NPY in the hypothalamus results in hypophagia and polydipsia, while the implication of increased NPY in the pancreas of diabetic rats is not clear.

Effects of Danqidihuang Granules on glucolipid metabolism in insulin-resistant rats

OBJECTIVE： To explore whether the insulin resis- tance （IR） model could be established through feed- ing Sprague-Dawley （SD） rats high-sugar and high-fat diets and to further observe the preven- tive and treatment effects of different doses of Dan- qidihuang Granules in rats. METHODS： Thirty-two SD rats were divided ran- domly into control group A （given regular feed）, model group B （food high in sugar and fat）, inter- vention group C （food high in sugar and fat as well as regular doses of Danqidihuang Granules）, and in- tervention group D （food high in sugar and fat as well as double doses of Danqidihuang Granules）. The interventions were for 8 weeks. Motion, change in color, body weight, and food intake, as well as plasma lipids （including low-density lipopro- tein-cholesterol （LDL-C）, high-density lipopro- tein-cholesterol （HDL-C）, total cholesterol （TC） and triglyceride （TG）, fasting blood glucose （FBG）, fast-ing insulin （FINs） levels, insulin sensitivity index （ISI）, and insulin resistance index （HOMO-IR） were observed. RESULTS： At the end of the second week of the ex- periment, the appetite and activities of rats in groups B, C and D decreased significantly com- pared with group A. The fur of the rats in those three groups was curly. After the fourth week, the activities, food intake and color of rats in group B were worse than those in groups C and D, but there were no significant differences in weight （P〉0.05）. Compared with group A, LDL-C, TC, FBG and HO- MO-IR in model group 13 were increased significant- ly （P〈0.05）, whereas the FINs and ISI increased obvi- ously （P〈0.05）. The levels of LDL-C and TC in group D was decreased obviously compared with those in group C, and HOMO-IR in group D was less than that in group B CP〈0.05）. CONCLUSION： Danqidihuang Granules helped to prevent and improved the insulin resistance of rats.