No evidence of germ-line transmission by adenovirus-mediated gene transfer to mouse testes

Abstract

To investigate the risk of germ-line transmission of vector sequences after in vivo adenovirus-mediated gene transfer to mouse testes and to discuss whether an adenovirus vector could be used in the future to treat male factor infertility. Experimental animal study. Laboratory research setting in the Department of Nephro-urology at Nagoya City University Graduate School of Medical Sciences in Japan. Eight-week-old B6C3F1 mice. Adenovirus vector carrying a LacZ transgene as a marker was injected into the interstitial space (intratesticular injection) or seminiferous tubules (intratubular injection) of the mouse testis. An assessment by polymerase chain reaction (PCR) and histological analyses of the proportion of adenovirus vectors administered into the testis that can infect epididymal sperm and transmit to fetuses derived from these males 3, 7, 14, 28, and 35 days after intratesticular or intratubular adenovirus injection. No PCR signal was identified in genomic DNA extracted from the epididymal sperm of all mice on each day after intratesticular or intratubular adenovirus injection. On reverse transcriptase (RT)-PCR analysis of mRNA isolated from fetuses derived from these males on each day after intratesticular or intratubular adenovirus injection, no fetuses had amplified products, although about 30% of the fetuses generated by microinjection into fertilized eggs had LacZ transcripts. On histochemical staining, no two-cell and 12.5 d.p.c. fetuses showed beta-gal activity. These sperm and fetus studies showed that adenovirus-mediated gene transfer to the testis does not cause infection of or transmission to the germ line or fetuses. The risk of germ-line transmission after adenovirus-mediated gene transfer to the testis is extremely low, and this method can be exploited in the future for the treatment of male factor infertility.