The Study About The Influence That Folic Acid,Vitamin B₁₂ And Homocysteine Affect On The Type-2 Diabetes Mellitus Rats With Diabetic Nephropathy

Objective: To explore the relationship among the folic acid, Vitamin B₁2, Hyperhomocysteinemia and diabetic microangiopathy, to give the theoretical evidences for the pat ients to adopt some measures to prevent the occurrence of diabetic microangiopathy.Method:We selected 80 male SD rats, the weight of which were between 230～270g, and then divided them into 8 groups randomly. Those were the control group and the seven other groups used as the model groups, each group had 10 rats. During the process of this study, the control group were fed with the normal animal feeds, while the model groups were fed with the high calorie diets for 10 weeks to induce insulin resistance. At the end of the tenth week, the rats of the model group were induced to type 2 diabetes mellitus by intraperitoneal injection with streptozocin 30mg/kg. Two weeks later, we selected the type 2 diabetes mellitus rats from the seven model groups for the further study. We divided them into 4 groups according to the level of the fast blood glucose, those were DM group, DM+VitB₁2, DM+folic acid, DM+VitB₁2+folic acid. Then, we fed the five groups of rats with the same normal feeds for 2 months. We measured the levels of the homocysteine, the blood fat (cholesterin, triglyceride), Fins, FBG, ISI, SOD, MDA, GSH-PX, Microalbuminuria. The periodic acid Schiff staining on the kidney and the immunohistochemistry about MMP-9 were analyzed.Results:After feeding the rats of the seven model groups with the special feeds for 10 weeks, most of the rats showed the hyperinsulinism, the differences of the weight and the blood-fat like cholesterin, triglyceride between the model groups and the control group were significant. (p＜0.05). After injecting with STZ (streptozocin), two weeks later, all of the differences of FBG, Fins, HOMA-IR, ISI and weight between the groups of type 2 diabetes mellitus rats and the control group were significant. (p＜0.05). The levei of homocysteine of the diabetes mellitus rats of the group without any intervention had the tendency of rising, the relationship between the level of hornocysteine and the degree of renal lesions showed the positive correlation(p＜0.05). The expression of MMP-9 protein was increased in the diabetes mellitus rats of the group without any intervention (p＜0.05). The supplement with folic acid and Vitamin B₁2 had the effect of lowering the level of homocysteine of the diabetes mellitus rats(p＜0.05). The diabetic microangiopathy of the four groups of diabetes mellitus rats with different interventions were not so serious as the diabetes mellitus rats without any interventions, and the mechanism of the protective effect of the supplement with folic acid and Vitamin B12 may have something to do with the effect of anti-oxygenation and the degradation of the MMP-9 protein..The relationship between the level of folic acid and Vitamin B₁2 showed the positive correlation, (r_s=0.555p＜0.05), while the relationships between the folic acid and homocysteine, Vitamin B₁2 and homocysteine showed the negative correlation (r_s1= -0.201 r_s2= -0.563, p＜0.05)Conclusions:1. Using the special feeds to feed the SD rats for ten weeks can induce them to have the state of IR (insulin resistance), then injecting STZ (30mg/Kg) from abdominal cavity can make them develop to be type 2 diabetes mellitus.2. The level of homocysteine of the diabetes mellitus rats of the group without any intervention has the tendency of rising, the level of homocysteine will affect on the degree of renal lesions. The supplement with folic acid and Vitamin B₁2 has the effect of lowering the level of homocysteine of the diabetes mellitus rats.3. The supplement with folic acid and Vitamin B₁2 had the effect of protecting the capillary of the kidney from damage, and the mechanism may have something to do with the effect of anti-oxygenation and the degradation of the MMP-9 protein.