Collagen Changes of the Corpus Cavernosum in Streptozotocin-Induced Diabetic Rats and the Effects of Insulin and Aminoguanidine

Kim, Kun Suk; Hong, Jun Hyuk; Ahn, Tai Young

Abstract

PURPOSE
Diabetes changes the properties of collagen in our body tissue, increasing cross-linked collagen via nonenzymatic glycosylation and accumulation of advanced glycosylation end products. Glucose-derived cross-linked collagen formation may contribute to the development of chronic diabetic complications such as decreasing the compliance of tissue. Aminoguanidine, a hydrazine compound, prevent formation of glucose-derived collagen cross-linking. We studied the change of the properties of collagen in the corpus cavernosum by diabetes and the effects of insulin and aminoguanidine.
MATERIALS AND METHODS
Diabetes was induced in male Sprague-Dawley rat and maintained for 12 weeks. Rats were divided into four groups: 1) control, 2) diabetics, 3) diabetics treated with insulin, 4) diabetics treated with aminoguanidine. Concentration of collagen in cavernosal tissue was measured by hydroxyproline content and expressed as hydroxyproline (micro gram) / dried defatted tissue (mg). The characteristic autofluorescence of glycosylated connective tissues of penile tissue was used to quantitate advanced glycosylation end products.
RESULTS
The content of collagen in cavernosal tissue was not significantly different among experimental groups. Cross-linked collagen expressed as fluorescence (U/micro gram hydroxyproline) was increased in diabetic group (61.6+/-5.1) compared to control group (24.1+/-3.2) and it was decreased in both insulin-treated group (36.9+/-7.4) and aminoguanidine-treated group (37.9+/-5.8) compared to diabetic group.
CONCLUSIONS
Our studies revealed that the properties of collagen in corpus cavernosum was changed by diabetes and that aminoguanidine as well as insulin prevented the diabetes-induced crossed linked collagen formation.