STEREOLOGICAL STUDY OF COLLAGEN IN THE AGING OF URINARY BLADDER IN RATS

Abstract

BACKGROUND: The aging process is inevitable and culminates in functional worsening of multiple systems, including the urinary bladder. Functional alterations of the bladder are recognized, as well as the importance of connective tissue and collagen to normal bladder functions. However, little is known about which are the structural alterations suffered by bladder in the aging process. PURPOSE: To describe and to quantify histological alterations related to collagen types I and III through stereology in rats submitted to the process of aging urinary bladder. METHODS: Seventy-two Wistar rats were divided in six groups. Each group was sacrificed in different ages: 3, 6, 9, 12, 18 and 24 months. It was removed the urinary bladder and performed stereological and histological analysis of the bladder tissue’s collagen (volumetric density of collagen types I and III, and their relative frequencies). RESULTS: Between groups 1 (3 months) and 2 (6 months) there was a statistically significant increase in collagen type III. When compared groups of younger rats (3-12 months) to older rats (18-24 months), a significant decrease of volumetric density of collagen type III (p <0.05) is noticed. As for collagen type I, the highest relative frequency occurred at 12 months and suffered a decrease in the older groups 5 and 6 (p <0.05). CONCLUSIONS: There are significant alterations in volumetric densities of collagen types I and III with the aging of the urinary bladder. We observed a decrease in volumetric density of collagen type III when compared younger to older rats