Nanomicelle curcumin-induced DNA fragmentation in testicular tissue; Correlation between mitochondria dependent apoptosis and failed PCNA-related hemostasis

Abstract

Current study was done to assess possible anti-proliferative effect of nanomicelle curcumin (NMCM) against germ cells in testicular tissue. For this purpose, 24 mature male Wistar rats were divided into control and test groups. The animals in test groups received 7.5mg/kg, 15mg/kg and 30mg/kg of NMC (NO=6 rats in each group). Following 48days, the expression of Bcl-2, Bax, caspase-3, P53 and proliferating cell nuclear antigen (PCNA) were evaluated by using reverse transcription-PCR and immunohistochemistry. Histological changes, tubular differentiation index (TDI), tissue cellularity and serum level of testosterone were analyzed. Finally, the DNA laddering test was used to assess the DNA fragmentation as hallmark for apoptosis. The NMCM significantly (P<0.05) diminished the Bcl-2, p53 and PCNA and enhanced the Bax and caspase-3 mRNA levels. The NMCM significantly (P<0.05) elevated the percentage of Bax and caspase-3-positive tubules and remarkably reduced the percentage of tubules with positive reaction for Bcl-2, p53 and PCNA. The NCMN-received animals exhibited remarkable (P<0.05) reduction in cell population, TDI ratio and serum level of testosterone. Severe DNA fragmentation was observed in 30mg/kg NMCM-received group. In conclusion, the NMCM by reducing the testicular endocrine status, down-regulating Bcl-2 expression and by enhancing the Bax and caspase-3 expression initiates the intrinsic apoptosis pathway. On the other hand, inhibited expression of p53 and PCNA (at dose level of 30mg/kg) suppresses the p53 and PCNA-related hemostasis/preservative reactions. All these alterations adversely affect the spermatogenesis.