en Original Article Original Article - Materials and Methods: Young adult Sprague-Dawley rats (200-250g) were assigned into one of the three different groups of control, SCI, and adenovirus transfer (Ad) (n=3/ group). Control rats received no injury, nor any surgery. For SCI rats, SCI was produced by a 10g brass rod with a tip diameter of 2 mm which was dropped from a height of 12.5 mm onto exposed spinal cord at level of T10 with NYU impactor. Animals were perfused transcardially 43 days post SCI. Both spinal cord and testicular tissues were cryo-sectioned and ultra thin-sectioned, respectively. Cellular morphology and morphometry were done for spinal cord tissues. The testicular samples were processed for both light and transmission electron microscopy (TEM). The third group of rats underwent SCI first, followed by microinjection of LacZ adenoviral vectors (5x106 p.f.u./ �l) along the T6-T10 dorsal root entry zone bilaterally. The immune system of animals were suppressed before the Ad administration. Each Ad injection was done using a glass micropipet and a Nonoject injector. Rats were killed 43 days after Ad injections, and the tissues were studied as for other groups. Spinal cord injury, Gene therapy, Spermatogenesis, Rat 7 11 http://ijrm.ir/browse.php?a_code=A-10-100-18&slc_lang=en&sid=1 Mohammad A Khalili Yes Alexander G Rabchevsky No