[Effects of interferon-gamma and tumor necrosis factor-alpha on the fertilizing capacity of human sperm and their mechanisms].

OBJECTIVE: To investigate the effects of interferon-gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-gamma) on the sperm acrosin activity and the rate of acrosome reaction and to probe into their mechanisms. METHODS: Thirty-six nearly normal semen samples were treated with IFN-gamma and/or TNF-alpha after isolated by 75% Percoll. The sperm acrosin activity was tested by the method of BAEE/ADH Unity, the rate of acrosome reaction observed by Triple-stain technique, the NO concentration measured by HPLC and the activities of Na+ -K+ -ATPase, Ca2+ -ATPase and SOD assayed by kit method. RESULTS: Both IFN-gamma and TNF-gamma could decrease sperm acrosin activity and acrosome reaction (P < 0.05 or P < 0.01). TNF-alpha showed stronger inhibiting effect, IFN-gamma markedly reduced the activities of Na+ -K+ -ATPase, Ca2+ -ATPase and SOD in sperm (P < 0.01), and their synergistic action was weaker. However TNF-alpha produced hardly any effect on Na+ -K+ -ATPase and Ca2+ -ATPase. The NO concentration in sperm was significantly increased by IFN-gamma and/or TNF-alpha (P < 0.01). CONCLUSION: IFN-gamma and TNF-alpha have some inhibiting effect on sperm acrosin activity and the rate of acrosome reaction, which could be attributed to their influence on the activities of Na+ -K+ -ATPase, Ca2+ -ATPase and SOD, the NO concentration and so on.

Role of polyamines in myocardial ischemia/reperfusion injury and their interactions with nitric oxide.

Polyamines (putrescine, spermidine, and spermine) are present in all higher eukaryotic cells and are essential for cell growth, differentiation and apoptosis. Sharing common precursor with polyamines, nitric oxide (NO) is associated with myocardial ischemia/reperfusion injury by the generation of peroxynitrite. Although polyamines have been implicated in tissue ischemia injury, their metabolism and interactions with NO in myocardial ischemia/reperfusion injury have not been fully understood. In our experiment, when Langendorff perfused rat hearts were subjected to 40 min ischemia without reperfusion, both ornithine decarboxylase (ODC) and Spermidine/spermine N(1)-acetyltransferase (SSAT) activities were up-regulated and putrescine accumulated. While after reperfusion, ODC activity decreased and SSAT activity increased, resulting in putrescine accumulation and decreased spermidine and spermine. Meanwhile NO content was increased. In addition, sodium nitroprusside (SNP, a NO donor) decreased ODC activity in cardiac tissue homogenate but increased SSAT activity in a dose-dependent manner. Pre-treatment of isolated heart with N(omega)-nitro-L-arginine methyl ester hydrochloride (L-NAME, an inhibitor of NO synthase) increased ODC activity. Exogenous spermine (1 mM) administration prior to ischemia prevented spermine decrease, reduced cardiac myocyte necrosis and apoptosis, and promoted the recovery of cardiac function after ischemia/reperfusion. These results suggest that acute heart ischemia activates myocardial polyamine stress response characterized by increased ODC and SSAT activities and accumulation of putrescine. Ischemia/reperfusion disturbs polyamine metabolism, and the loss of spermine might be associated with NO increase and thereby influences myocardial cell viability. Exogenous spermine may protect the hearts from myocardial ischemia/reperfusion injury.

[The changing trends of expression of VEGF and its relationship with the levels of NO in rat corpus luteum of pseudopregnant].

AIM: The expression of VEGF in rat ovaries corpus luteum and its expression pattern were observed to investigate the effect of VEGF on luteal formation and regression. METHODS: The model of immature rat of pseudopregnant was established using pregnant mare's serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG), the expression of VEGF in corpus luteum was detected by immunohistochemistry, the levels of VEGF in corpus luteum was measured by ELISA, and the levels of NO in corpus luteum was measured by chemistry assay. RESULTS: VEGF expressed weakly in rat corpus luteum on the day 1, and enhanced gradually from day 3 to day 5, then went up to the peak on the day 7, and maintained to day 9. On the day 11, the expression of VEGF began to decrease. The levels of VEGF were similar to the expression of VEGF. The levels of NO appeared like double wave. The levels increased gradually from day 1 to day 5, and peaked on the day 7, then decreased on the day 9, while lightly increased on the day 11, and showed significant increase and reached the highest on the day 13, then decreased the lowest on the day 15. CONCLUSION: There is a intimate temporal relationship between the expression of VEGF and angiogenesis in corpus luteum, VEGF may play a role in luteum formation by improving angiogenesis mediated by NO, NO may play a role in luteum regression as a luteolytic during the late luteal phase.

[Effect of gamma-aminobutyric acid on the sperm acrosin activity].

OBJECTIVES: To investigate the effect of gamma-aminobutyric acid (GABA) on the sperm acrosin activity in normal men and positive antisperm antibody (AsAb) men. METHODS: Sperm acrosin activity was detected by BAEE/ADH method. RESULTS: GABA could increase the sperm acrosin activity in normal and AsAb positive patients (P < 0.01). The results also indicated that GABA significantly increased Na(+)-K(+)-ATPase activity (P < 0.01), Ca(2+)-ATPase activity (P < 0.05) and SOD activity (P < 0.01) of sperm. CONCLUSIONS: The results demonstrated that GABA could influence the sperm acrosin activity.