|Wise, Thomas -|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 23, 2009
Publication Date: August 1, 2009
Repository URL: http://handle.nal.usda.gov/10113/33985
Citation: Ford, J.J., Wise, T.H. 2009. Sertoli Cell Differentiation in Pubertal Boars. Journal of Animal Science. 87(8):2536-2543. Interpretive Summary: Two markers of Sertoli cell maturation in rodents, anti-Mullerian hormone and p27kip1 protein, a cyclin-dependent kinase inhibitor, were evaluated in testes of two distinct genetic lines of boars to determine their patterns of expression from birth to early puberty. The two lines of boars, Meishan and BX, differ greatly in their age of sexual maturity. Pubertal development was characterized by declining AMH expression followed by increasing expression of p27kip1 in Sertoli cell nuclei and subsequent expansion of seminiferous tubules. These pubertal changes occurred at significantly younger ages in Meishan than in BX boars. Moreover, these patterns of change progressed from the center of the testis outwardly. These studies document that anti-Mullerian hormone and p27kip1 are markers of Sertoli cell maturity in boars. Boars have a more prolonged period of pubertal development than rodents; thus, the findings from these studies are of great interest to other investigators seeking an animal model to examine the interactions among various physiological factors that determine the number of Sertoli cells that exist at sexual maturity. Sperm production increases with increasing number of Sertoli cells.
Technical Abstract: Meishan boars experience puberty at a younger age than crossbred (BX) boars in association with earlier cessation of Sertoli cell proliferation and smaller post pubertal testicular size. The current study defined changes in expression, assessed by immunohistochemistry, of anti-Mullerian hormone (AMH) and p27kip1, markers of Sertoli cell differentiation, in prepubertal Meishan and BX boars and related these changes with the pubertal expansion of seminiferous tubules. Expression of AMH in tubules of Meishan and BX boars increased from 7-28 d of age. Pubertal development was characterized by declining AMH expression followed by increasing expression of p27kip1 in Sertoli cell nuclei and subsequent expansion of tubules. These pubertal changes occurred at significantly younger ages in Meishan than in BX boars. In testes of 90-d-old BX boars, expression of p27kip1 in Sertoli cell nuclei and tubular diameter increased from the mediastinum relative to the tunica. Evaluation of the same tubules in adjacent sections established that expression of AMH decreased followed by expression of p27kip1 in Sertoli cell nuclei; both changes occurred before tubular diameter achieved 90 µm. In boars unilaterally castrated at 90 d of age, tubular diameter was inversely related to weight of the remaining testis at 10 months supporting terminal differentiation of Sertoli cells in a sub-population of these boars. These studies established temporal relationships of AMH, p27kip1 and seminiferous tubule diameter in pubertal boars of 2 genetically diverse lines and determined that differentiation of Sertoli cells progresses as a gradient from the mediastinum toward the tunica.