Adenovirus-mediated gene transfer to rat testis in vivo.

To study transgene expression in the adult rat testis in vivo, an adenovirus vector carrying a lacZ transgene with a nuclear localization signal was used as a marker. The adenovirus vector was first tested on rat Sertoli cell-germ cell cocultures in vitro; it efficiently mediated transgene expression in Sertoli cells but not germ cells. This vector was then delivered to the interstitial compartment of adult rat testes by intratesticular injection, resulting in Leydig cells expressing the transgene. Alternatively, delivering the vector to the intratubular compartment by rete testis injection resulted in expression of the transgene by Sertoli cells of the seminiferous epithelium and principal cells of the epididymis. In vivo, each cell type expressed the transgene by 2 days postinfection, and expression persisted for at least 10 days; however, later time points were associated with a loss of transgene expression and focal interstitial inflammation. This study documents the ability of adenovirus to mediate gene transfer to specific testicular cells, providing a powerful tool to study the short-term effects of specific genes on spermatogenesis in vivo.