The Effect of Insulin Therapy on the Collagen of the Corpus Cavernosum in Diabetic Rat

Lee, Hyun Bo; Yoon, Jai Young; Hwang, Tae Kon

Abstract

PURPOSE: The purpose of this study was to investigate the changes of collagen and the effect of insulin therapy on the collagen of the corpus cavernosum in diabetes mellitus(DM).
MATERIALS AND METHODS
Twenty seven rats were included for this study and divided into control, diabetic and insulin treated diabetic group. DM was induced by intravenous injection of streptozotocin 65mg/kg and NPH insulin (initially 4IU/d for 3 days and then 6IU/d) was administered for 4 weeks for insulin treatment. After 4 weeks of experiment, the collagen concentration was evaluated with hydroxyproline quantitative analysis and collagen distribution within the corpus cavernosum. Collagen(type I, III and IV) was obsened with Masson-trichrome and immunohistochemical staining.
RESULTS
1. Body weights of control, diabetic group and insulin treated diabetic group were 315.0 +/-14.2gm, 230.8+/-15.2gm and 310.1+/-15.4gm, respectively, at 4 weeks of experiment. Control and insulin treated diabetic group progressively increased in body weight(p<0.05), while diabetic group decreased in body weight. 2 Collagen concentration of control, diabetic and insulin treated diabetic group expressed 465.2+/-24microgram, 590.3+/-43.7microgramand 567.1+/-34.8microgram respectively. Collagen concentration in corpus cavemosum significantly increased in diabetic and insulin treated diabetic group compared with control group(p<0.05). No significant difference was noted between diabetic and insulin treated diabetic group. 3. Immunohistochemical staining revealed collagen types I and III were distributed evenly in the corporal interstitial tissue, but type IV collagen was noted along the basement membrane of the cavernosal sinusoid in the both control and experimental groups. Collagen type 1 of diabetic and insulin treated diabetic group, as compared with control group, was noted thin staining in the corporeal tissue. There were no significant differences in collagen type 111 among control, diabetic and insulin treated diabetic groups. Collagen type IV of diabetic and insulin treated diabetic group, as compared with control group, was noted dense staining in the basement membrane of the cavernosal sinusoidal space. And the intensity for collagen type IV was not significantly different between diabetic and insulin treated diabetic group. 4. Masson-trichrome staining showed no significant differences among control, diabetic and insulin treated diabetic groups.
CONCLUSIONS
These results suggest that the DM changes quantitatively the collagen type IV of corpus cavernosum and the insulin treatment had no effect on the collagen alteration in DM.