The objective was to find out the functional roles of hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) during various stages of meiotic cell cycle and apoptosis in rat oocytes. For this purpose, 30 oocytes from each stage such as diplotene, metaphase-I (M-I), metaphase-II (M-II) and apoptosis were collected and intracellular H(2)O(2), total nitrite level and inducible nitric oxide synthase (iNOS) expression were analysed. This study demonstrated that generation of a tonic level of H(2)O(2) induces meiotic resumption in diplotene-arrested oocytes and further increase may lead to apoptosis. Conversely, reduction in iNOS expression and total nitrite level are associated with meiotic resumption in diplotene-arrested oocytes, but induce apoptosis in aged oocytes. These results suggest that generation of a tonic level of H(2)O(2), reduced iNOS expression and total nitrite level are associated with meiotic resumption, while more generation of H(2)O(2) and sustained reduced total nitrite level are linked with oocyte apoptosis in rat.

No abstract

No abstract

EARP was found to have the best sensitivity; ToPAS II had the highest specificity. A major limitation of the study design was the exclusion of pre-existing rheumatological diseases.

The present study was designed to investigate whether verapamil could inhibit spontaneous parthenogenetic activation in aged rat eggs cultured in vitro. Eggs collected from oviduct after 19 h post human chorionic gonadotropin (hCG) were arrested at the metaphase-II (M-II) stage and exhibited a first polar body. Culture of these aged eggs in calcium/magnesium (Ca(2+)/Mg(2+))-deficient and serum-free medium for 3 h induced exit from M-II, a morphological sign of spontaneous parthenogenetic activation in all eggs. However, verapamil reversibly inhibited spontaneous parthenogenetic activation in a dose-dependent manner. Further, lower doses (6.25, 12.5, and 25 muM) of verapamil induced egg survival, while higher doses (50 and 100 muM) were associated with the appearance of morphological apoptotic features such as shrinkage, membrane blebbing and cytoplasmic granulation prior to degeneration. The DNA fragmentation was induced [as evidenced by terminal deoxynucleotidyl transferase (TdT) nick-end labeling (TUNEL) positive staining] in eggs undergoing morphological apoptotic changes. On the other hand, caspase-3 inhibitor (1 muM) partially inhibited morphological apoptotic changes (44.34+/-3.53%) suggesting the involvement of both Ca(2+)and caspase-3-mediated apoptotic pathways. These findings suggest that verapamil reversibly inhibits spontaneous parthenogenetic activation and induces egg survival at lower doses, while higher doses induce cell death via apoptosis.