p53 expression and apoptosis in varicocele in the rat testis

We investigated the presence of p53 expression and apoptosis in an experimental model of varicocele in the rat.

A total of 30 adult male Sprague-Dawley rats were studied in 3 groups, namely group 1-13 with varicocele, group 2-9 with sham operation and group 3-8 controls. All animals underwent orchiectomy after 30 days and sections of the left testis from each animal were studied. TUNEL was used to detect apoptotic germ cells and an apoptotic index (AI) was calculated for each testis specimen. p53 expression was determined immunohistochemically and graded according to the proportion of cells stained in each specimen.

AI values in group 1 testes were 0% to 0.51% (mean 0.06% +/- 0.13%) and the corresponding range in group 2 was 0.04% to 0.69% (mean 0.25 +/- 0.21%). No group 3 control specimens showed TUNEL staining (AI 0% in all). Although the mean AI in group 1 was higher than that in controls, this difference was not statistically significant (p = 0.318). The mean AI value in group 2 was significantly higher than in the control group (p = 0.021) but it was comparable to that in group 1 (p = 0.099). Seven (53.8%) and 2 (22.2%) specimens in groups 1 and 2, respectively, showed p53 staining in germ cell nuclei. None of the specimens in group 3 showed nuclear p53 expression. The grade of p53 expression in group 1 was significantly higher than that in groups 2 (p = 0.042) and 3 (p = 0.011). Expression grades in groups 2 and 3 were not significantly different (p = 0.426).

To our knowledge p53 expression that may reflect abnormal spermatogenesis has been documented for the first time in an experimental model of varicocele in the rat testis. In contrast to other investigations, no link between apoptosis and varicocele was detected.