High glucose inhibits the collagen expression of SMCVs in diabetes and participates in the development of diabetic venous disease

Abstract

Objective To determine the influence of diabetes on histological profile of lower limb veins, and to explore the mechanism of the effects of high-glucose medium in the viability and Collagen expression of venous smooth muscle cells (SMCV). Methods Diabetic rat model was established with intraperitoneal injection of streptozotocin. Hematoxylin-eosin (HE) and Masson staining were performed to observe the histological changes of great saphenous veins (SV). SMCVs were cultured in medium of high (DM group) or normal (NC group) levels of glucose, and the SMCVs viability was evaluated by cell counting kit-8 (CCK-8). The levels of TypeⅠ Collagen (COLⅠ), Type Ⅲ Collagen (COL Ⅲ), Metalloproteinase 2 (MMP2), Tissue inhibitor of metalloproteinase 1 (TIMP1) protein and mRNA expression in the cells were detected by Western Blot (WB) and Real-time quantitative Polymerase Chain Reaction (RT-qPCR). The contents of COLⅠ and COL Ⅲ in the cellular supernatant were detected using ELISA kit. Results Vein samples acquired from the diabetic rats showed lower medial thickness (P 0.05) and lower collagen content (P>0.05). The viability of VSMCs was significantly declined in the DM group (P<0.05). There was no significant difference in the expression of COLⅠ mRNA between groups. The levels of COL Ⅲ mRNA was decreased in the DM group (P<0.05), followed by an ascending level of TIMP1 mRNA (P<0.05) and a declined level of MMP2 mRNA (P<0.05). WB analysis demonstrated that high-glucose treatment decreased the expression of COLⅠ and TIMP1 in SMCVs, accompanied with an increased expression of MMP2. ELISA showed that the expression of COLⅠ (P<0.05) and the ratio of COLⅠ / COL Ⅲ (P<0.05) in the cellular supernatant of DM group were also decreased. Conclusions The lower limb veins in diabetes presented histological changes as a lower medial thickness, larger luminal area and lower collagen content. High glucose treatment decreased the expression of COLⅠ and TIMP1 of SMCVs, and increased the expression of MMP2, which may suggest that high glucose inhibit the collagen expression of SMCVs via the regulation of MMP2/TIMP1 expression. Key words: Diabetes mellitus; Chronic venous disease; Extracellular matrix; Collagen