Investigation of Age-Related Changes in Expression of Aquaporin-1 and Aquaporin-3 in Rat Bone

Aim: Aquaporins are membrane channel proteins that transport water and ions. The amount of aquaporins in tissue changes with age. The amount of aquaporin-1 (AQP1) and aquaporin-3 (AQP3) is considered to decrease in cartilage tissue with age. However, no age-related change has been reported regarding the amount of aquaporins in bone tissue. In this study, our aim was to examine expressions of AQP1, AQP3, and type I collagen immunohistochemically in the bone tissues of young and old rats. Material and Method: Fourteen Wistar Albino rats were included in this study. Group I (n=7) consisted of young rats that were two months old, while Group II (n=7) consisted of old rats that were eighteen months old. Bone tissue (femur) was dissected and examined histopathologically and immunohistochemically. After routine histological procedure, sections at 4-5 µm thickness were obtained from tissues embedded in paraffin. Sections were stained immunohistochemically for AQP1, AQP3, and type I collagen as well as with hematoxylin-eosin. Results: Immunohistochemically, expressions of AQP1, AQP3, and type I collagen were demonstrated in both young and old rats. AQP1, AQP3, and type I collagen amounts were found to decrease with aging. Discussion: Our findings suggest that reduced amounts of AQP1 and AQP3 may be related to age-related changes in bone tissue