Differential expression of transforming growth factor-beta in the interstitial tissue of testis during aging.
Transforming growth factor-betas (TGF-betas) have significant effects on testis development. The pattern of TGF-beta expression in aging testis has not been established to date. We examined age-related changes in the expression of TGF-beta and its receptors in the testis using Western blot analysis. TGF-beta1 expression increased continuously in aging rat testis, whereas no age-associated changes were observed for TGF-beta3. Strong expression of TGF-beta2, as well as type I and II receptors was observed in 12-month-old testis, but following this time, expression decreased dramatically. Interestingly, TGF-beta2 and -beta3 displayed strong and similar expression patterns in liver, regardless of age, suggesting that the down-regulation of TGF-beta2 is testis-specific. We observed significant induction of p53 and p21WAF1 in 18-month-old testis that appeared to correspond with aging. Moreover, caloric restriction (CR) prevented age-related decrease in TGF-beta2 expression. Using immunohistochemistry, we showed that all TGF-beta1, -beta2, and -beta3 proteins are expressed primarily in interstitial cells, which are located in the space between adjoining seminiferous tubules. Our data collectively indicate that aging in the testis is regulated by differential expression of TGF-beta proteins, and decreased levels of TGF-beta2 contribute to the aging process.
Jung
Jae-Chang
JC
Department of Biology, College of Natural Sciences, Kyungpook National University, Taegu 702-701, Korea.
Park
Geun-Tae
GT
Kim
Kook-Hee
KH
Woo
Ju Hyung
JH
An
Jung-Min
JM
Kim
Ki-Chul
KC
Chung
Hae Young
HY
Bae
Young-Seuk
YS
Park
Jeen Woo
JW
Kang
Shin-Sung
SS
Lee
Young-Sup
YS
D000375:Aging / Q000378:metabolism*; D000818:Animals; D015536:Down-Regulation; D007120:Immunochemistry; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013737:Testis / Q000033:anatomy & histology / Q000378:metabolism* / Q000648:ultrastructure; D016212:Transforming Growth Factor beta / Q000032:analysis / Q000378:metabolism*
D016212:Transforming Growth Factor beta