Effect of Grape Seed Proanthocyanidins Extract (GSPE) on Skin Collagen Metabolism in Type II Diabetic Rats

Purpose: To observe the effect of grape seed proanthocyanidins extract(GSPE) on skin collagen metabolism and its possible mechanism in type Ⅱ diabetic rats.Methods: In order to establish type Ⅱ diabetic rat model,male SD rats were injected with streptozotocin(STZ,0.01 mol/L,30 mg/kg) after being fed high-fat diet for 4 weeks.Then the diabetic rats were randomly divided into diabetes-vehicle group(DM control group) and three GSPE treatment groups.Rats fed normal diet were randomly divided into normal and GSPE control group.The dose of GSPE control group was 250 mg/(kg.d),and the doses of three GSPE treatment groups were 125,250,500 mg/(kg.d),respectively.After administration for 12 weeks,the body weight,fasting blood glucose(FBG),skin glucose concentration and hydroxyproline content were measured.Paraffin-embedded skin sections were stained by hematoxylin-eosin(HE) and Masson,and then examined under a microscope.The thickness of skin was measured with Image-Pro Plus 6.0.Insulin like growth factor-1(IGF-1) and collagen III in rat footpad were detected by immunohistochemical method.Results: Compared with the DM control group,FBG values were decreased but there was no significant difference in threeGSPEtreatmentgroups(P 0.05).GSPE at the high dose revealed a significant reduction in glucose concentration of skin tissues when compared with the DM control group(P 0.001).In contrast,each GSPE dose group could significantly increase skin hydroxyproline content(P 0.05).After stainingskintissuesbyHEandMasson,weobservedthatGSPEcouldinhibitthe skin to be thin in diabetic rats.Compared with the DM control group,the footpad in the GSPE high-dose group had higher IGF-1 and collagen III expression.Conclusion: GSPE has improvement effect on skin collagen metabolism of type Ⅱ diabetic rats.