Aquaporin-1 and Aquaporin-3 Expressions in the Intervertebral Disc of Rats with Aging

Objective: The intervertebral disc (IVD) undergoes biochemical and morphologic degenerative changes during the process of aging. Aquaporins (AQPs) are a family of water channel proteins that facilitate water and small solute movement in tissues and may have a potential role in the aging degeneration of IVDs. One of the important problems in understanding disc degeneration is to find cellular molecules which contribute to the pathogenesis of IVDs. XThe aim of this study was to demonstrate the expression of aquaporin 1 and 3 in nucleus pulposus (NP), annulus fibrosus (AF) cells of rat lumbar intervertebral discs from both young and aged animals using immunohistochemistry.Material and Methods: Twenty Wistar-albino rats were included in the study. The rats were separated into two groups: 2-month-old rats (n=10) as the young group, 18-month-old rats (n=10) as the old group. The intervertebral disc tissues obtained from the lumbar spine (L1–L4, 4 discs) were used for immunohistochemical staining of AQP-1 and 3. Results: This study demonstrated that AQP-1 and AQP-3 immunoreactivity significantly decreased in NP and AF of aged rats compared to the young rats. Conclusion: We suggest that AQP-1 and 3 may contribute to the age related degeneration of the intervertebral disc

Yaşlanmayla sıçan kemiğindeki aquaporin-1 veaquaporin-3 ekspresyonu değişikliklerinin araştırılması

Amaç: Aquaporinler su ve iyon transportu sağlayan membran kanal proteinleridir. Yaşlanma ile dokulardaki aquaporinlerin miktarı değişmektedir. Aquaporin-1 (AQP1) ve aquaporin-3 (AQP3)'ün kıkırdak dokuda yaşlanma ile azaldığı gösterilmiştir. Ancak kemik dokuda yaşlanma ile aquaporinlerin miktarında değişim gösterilmemiştir. Bu çalışmada genç ve yaşlı hayvanların kemik dokularında AQP1, AQP3 ve tip I kollajen ekspresyonlarının immünohistokimyasal olarak araştırılması amaçlandı. Gereç ve Yöntem: Bu çalışmada 14 adet Wistar Albino cinsi sıçan kullanıldı. Grup I (n7) iki aylık genç sıçanlardan, Grup II (n7) onsekiz aylık yaşlı sıçanlardan oluşmaktaydı. Kemik dokusu (femur) histopatolojik ve immunohistokimyasal değerlendirme için alındı. Rutin histolojik prosedürün ardından parafine gömülen dokulardan 4-5 µm kalınlığında kesitler alındı. İmmunohistokimyasal olarak AQP1, AQP3 ve tip I kollajen boyama ayrıca Hematoksilen-eozin boyama yapıldı. Bulgular: Genç ve yaşlı sıçanlarda immünohistokimyasal olarak AQP1, AQP3 ve tip I kollajen ekspresyonu gösterildi. Yaşlanma ile AQP1, AQP3 ve tip I kollajen miktarında azalma olduğu gözlendi. Tartışma: AQP1 ve AQP3 mik tarındaki azalmanın kemik dokuda yaşa bağlı değişikliklerle ilgili olabilece ği kanaatindeyizAim: 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 (n7) consisted of young rats that were two months old, while Group II (n7) 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 agerelated changes in bone tissue