Abstract:

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
three GSPE treatment groups (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 staining skin tissues by HE and Masson, we observed that GSPE could inhibit the
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.

Key words: grape seed proanthocyanidins extract (GSPE), type Ⅱ diabetes, collagen metabolism, insulin like growth factor-1 (IGF-1), collagen Ⅲ