Histologic analysis of orchiopexy in a cryptorchid rabbit model

Although there is a consensus that very early orchiopexy is advantageous, there is little experimental data to support this view. Therefore, we studied early pre-pubertal versus later pre-pubertal orchiopexy in a cryptorchid rabbit model. Male offspring were divided into four groups with six to nine rabbits in each group: 1) controls (CON); 2) shams undergoing sham operations at both three weeks and two months of life (SHAM); 3) cryptorchid on day 3 with orchiopexy at three weeks and sham operation at two months (O3W); 4) cryptorchid on day 3 with sham operation at three weeks and orchiopexy at two months (O2M). All animals were sacrificed post-puberty at six months of age; the testes were fixed in situ by perfusion fixation, embedded in glycol methacrylate, and underwent morphometric analysis in a blinded fashion. The average seminiferous tubular diameter (STD) of the CON, SHAM, O3W, and O2M groups was 234, 160, 116, and 123 μm., respectively. The average testicular biopsy score count (TBSC) of the CON, SHAM, O3W and O2M groups was 9.0, 5.2, 3.5 and 3.5, respectively. There is no significant difference in STD or TBSC between the O3W and O2M cryptorchid groups, and values for both of these groups were significantly different from those of the SHAM group. In addition, a significant effect of sham operation was demonstrated. These results demonstrate no advantage of very early orchiopexy in this model, and are consistent with the clinical literature which, in general, shows reduced reproductive potential of a cryptorchid testis after orchiopexy.