The expression pattern of PARP-1 and PARP-2 in the developing and adult mouse testis

Although the importance of the PARP family members in the adult testis has already been acknowledged, their expression in the developing testis has not been addressed. We performed immunohistochemistry by using PARP-1 and PARP-2 antibodies on the developing mouse testis at embryonic day (E) 15.5, E17.5, postnatal day (PN) 0, PN3, PN9, PN20 and adult. Our results showed that at embryonic and early postnatal days, the expression of PARP-1 was in the nuclei of gonocytes and spermatogonia. PARP-1 was positive in interstitial cells with nuclear localization at all studied ages. At embryonic and early postnatal days, the expression of PARP-2 was in the cytoplasm of gonocytes and spermatogonia. During the progress of spermatogenesis, PARP-2 was localized in the cytoplasm of pre-leptotene spermatocytes on PN9, in the cytoplasm of pachytene spermatocytes on PN15 and in the cytoplasm of round spermatids on PN20. In the adult, PARP-2 staining can still be observed in the cytoplasm of spermatogonia, but to a much lesser degree than in the round and elongating spermatids. For all the studied ages, PARP-2 was positive in Sertoli cells and interstitial cells with cytoplasmic localization. Our results indicate that PARP proteins are present in germ and somatic cells during testis development in mice.