Ace-associated changes in collagen content and its subtypes within rat corpora cavernosa with computerized histomorphometric analysis

Objectives. To study the age-associated changes in the percentage of collag en and subtypes I, III, and IV within the corpora cavernosa in a rat model. Methods. The corpora cavernosa tissues were obtained from 30 male Wistar ra ts at three different ages. Processed with Masson's trichrome staining for collagen and with immunohistochemical staining for the collagen subtypes, t he values of the collagen percentage, the percentage of area, and relative proportion of each collagen subtype within the rat corpora cavernosa were m easured using an automatic image analysis system. The relationships between an increase in age and these parameters were analyzed. Results. The percentage of collagen within the corpora cavernosa was higher in the old rats (80 weeks) than in the young (20 weeks) and intermediate-a ge (40 weeks) rats (P = 0.02 and P = 0.25, respectively) and significantly increased with age (P = 0.021). The values of the percentage of area of col lagen subtypes III and IV also increased significantly with age (P = 0.039 and P = 0.019, respectively). The value of the percentage of area of collag en subtype I was not significantly increased (P = 0.159). Also, no signific ant differences were found in the relative proportions of all three collage n subtypes with age among the three age groups. Conclusions. The percentages df collagen within rat corpora cavernosa signi ficantly increased, but not strongly, with age, especially collagen subtype s III and IV. However, the relative proportion of each subtype did not chan ge with age. Therefore, we conclude that the amount of collagen may only pa rtly contribute to erectile dysfunction in the aging process of the rat. UR OLOGY 57: 837-842, 2001. (C) 2001, Elsevier Science Inc.