Modulatory effect of Coccinia indica on aortic collagen in streptozotocin-induced diabetic rats

1. The effects of Coccinia indica , an indigenous plant used in Ayurvedic medicine in India, on aortic collagen content and its characteristics were assessed in streptozotocin (STZ) diabetic rats. 2. Rats were made diabetic with a single intraperitoneal injection of STZ (45 mg/kg). Blood glucose, hydroxyproline, collagen, extent of glycation, collagen-linked fluorescence, soluble pattern of pepsin-soluble collagen, shrinkage temperature, alpha/beta ratio of type I collagen and type I/type III collagen ratio were determined in rats treated with C. indica leaf extract (CLEt; 200 mg/kg for 45 days using an oral intragastric tube). 3. In diabetic rats, the collagen content, as well as the degree of cross-linking, was increased, as evidenced by increased shrinkage temperature and decreased pepsin solubility. The alpha/beta ratio of type I collagen and the type I/type III collagen ratio of pepsin-soluble collagen were significantly decreased in STZ diabetic rats. 4. In conclusion, administration of CLEt for 45 days to STZ diabetic rats significantly reduced the accumulation and cross-linking of collagen. The effects of C. indica (collagen content 23.87 +/- 1.52 mg/100 mg tissue (t value = 6.80), extent of cross-linking 0.893 +/- 0.072 mg hydroxyproline/100 mg tissue (t value = 9.0)) were comparable with those of glibenclamide (collagen content 26.18 +/- 1.65 mg/100 mg tissue (t value = 4.58), extent of cross-linking 0.787 +/- 0.057 mg hydroxyproline/100 mg tissue (t value = 7.1)), a reference drug.