[Regulatory Role of Nitric Oxide in Development and Hatching of Mouse Blastocysts].

OBJECTIVE: To determine the regulatory role and mechanism of nitric oxide (NO) in the development and hatching of mouse blastocysts. METHODS: The Kunming female mice were superovulated and then mated with mature male mice. On the day 2.5 of their pregnancy, morulae were flushed from their uterine horns with culture media. Morulae were cultured in different concentrations of N-nitro-L arginine methyl ester (L-NAME), sodium nitroprusside (SNP), or the combination of L-NAME and SNP in culture media for 48 hours. The development and hatching of blastocysts were examined on day 4 and day 5 and the total numbers of blastocyst cells and cysteinyl aspartate specific proteinase 3 (caspase 3) were observed under confocal laser scanning microscope. RESULTS: With the increase of the concentration of L-NAME or SNP, the hatching rate of blastocysts and the total number of blastocyst cells were significantly reduced. The addition of 10 nmol/L SNP in culture media with 5 mmol/L L-NAME significantly increased the development of blastocysts and promoted hatching of blastocysts. However, with increase of SNP concentration in culture media with 5 mmol/L L-NAME, the development and hatching rates of blastocysts were significantly decreased. L-NAME had no obvious effect on the expression of active caspase 3 in blastocyst cells. However,when being above 500 nmol/L,SNP significantly increased the expression of caspase 3 in blastocyst cells. CONCLUSIONS: NO plays an important role in development and hatching of mouse blastocysts. Excessively high or low NO can damage the division of blastomeres, resulting in the failure of the blastocyst development and hatching. Also, excessively high NO can lead to the apoptosis of the blastocyst cells.

[Histone modifications during spermatogenesis and male infertility].

Many pathological phenomena of male infertility are related to epigenetic changes in male germ cells. Epigenetic regulation during spermatogenesis plays an important role in mitotic/meiotic divisions and spermiogenesis. The histones have various post-translational modifications on different amino acid residues during spermatogenesis. These modifications are crucial to the precise regulation of spermatogenesis. Moreover, the histone-to-protamine transition will occur during spermiogenesis. Many studies have also found that abnormal changes of histone modifications during spermatogenesis may damage the sperm development, leading to male sterility. This article reviews the changes of histone modifications during spermatogenesis, the regulation of the development of male germ cells, and the relationship between histone abnormalities and male sterility.

[Effects of bisphenol-A on blastocyst development and implantation].

OBJECTIVE: To determine the effects of bisphenol-A (BPA) on blastocyst development and implantation. METHODS: According to completely randomized grouping method, 90 pregnant mice were divided into 100, 300, and 600 mg/(kg·d)BPA groups and control group. BPA-treated pregnant mice were orally administered with BPA at concentrations of 100, 300 and 600 mg/(kg·d) from day 0.5 to day 3.5 of their pregnancy. Blastocyst implantation and development were studied. RESULTS: In the 300 mg/(kg·d) BPA group, the number of implantation sites and implantation rate were significantly decreased. In the 600 mg/(kg·d) group, no implantation sites were observed among pregnant mice and BPA inhibited embryo implantation. Blastocyst development on day 4 was examined, and findings showed that the development rate and total numbers of blastocysts in BPA treatment groups had no significant difference from the control group. However, BPA at 300 and 600 mg/(kg·d) significantly reduced blastocyst hatching rate and dramatically increased the number of blastocyst apoptotic cells when compared with those in the control group. CONCLUSION: BPA at a high concentration damages the blastocyst development before implantation and inhibits embryo implantation.

[Effects of bisphenol A on the female reproductive organs and their mechanisms].

Bisphenol A (BPA) is a commonly used phenolic environmental estrogen. Long-term exposure of female mammalians to BPA can lead to endocrine disorders, followed by the morphological and functional changes in ovary, uterus, vagina, and oviducts. The interactions of BPA with various target molecules or tissues will cause different effects. To further elucidate the effects of BPA on female reproductive system, we review the changes in the structure and functions of female reproduction system after BPA exposure and their possible mechanisms.

Polycomb group proteins and their roles in regulating stem cell development.

Polycomb group (PcG) proteins are a family of epigenetic regulators responsible for the repression of genes in proliferation and differentiation of stem cells. PcG protein complex consists of two important epigenetic regulators: PRC1 (polycomb repressive complex 1) and PRC2 (polycomb repressive complex 2). In order to further understand the functions of PcG proteins in stem cell growth and differentiation, we review the PcG protein composition, PcG protein localization in the target gene, PcG protein recruitment, and the functions of PcG proteins in the development of stem cells.

[An experimental study on injury of hippocampus neurons in rats by simulated push-pull maneuver of different degrees].

OBJECTIVE: To explore the degree of injury and phase of push-pull effect induced by different degrees of push-pull maneuver on hippocampus neurons in rats. METHOD: Injury of push-pull maneuver on hippocampus neurons in rats after different degrees of push-pull maneuver were determined by general evaluation of animal model, pathologic examination and electronic microscopy. RESULT: 1) General evaluation of animal model: the apoplexy index and the pathological grading increased with the increase of intensity of the push-pull maneuver. 2) Routine HE: No abnormity was found in appearance and distribution of hippocampus neurons in the control rats and various groups of +/-2 Gz exposures, and 30 min groups of +/-6 Gz, +/-8 Gz exposures, but denatured necrosis of neurons were found in 6 h and 24 h groups of +/-6 Gz, +/-8 Gz exposures. 3) Examination of ultrastructure under electronic microscope: No significant change were found in hippocampus neurons of CA1 area in 30 min and 24 h after +/-2 Gz exposures as compared with the normal control group. But various degrees of denatured necrosis of neurons were found in some of the hippocampus neurons of CA1 area in 6 h after +/-2 Gz exposures, 6 h and 24 h after +/-6 Gz and +/-8 Gz exposures. CONCLUSION: +/-6 Gz and +/-8 Gz exposures may cause injury of hippocampus tissues and it is most severe at 6 h after the +/-8 Gz exposures.

Effects of 14 single herbs on the induction of caspase-3 in tumor cells: a brief review.

Chinese medicines (CMs) are increasingly being used for the treatment of tumors because of their unique advantages. The induction of tumor cell apoptosis is an important method of tumor treatment. Caspase-3 is a member of the caspase (cysteine aspartic proteinases) family of enzymes, which are the major inducers of apoptosis. Caspase-3 activity is often measured in the context of research into anti-tumor drugs that target apoptosis. Many studies have shown that CMs upregulate the expression of caspase-3 in tumor cells via extrinsic and/or intrinsic pathways, removing endogenous suppression of apoptosis and promoting tumor cell death. Therefore, several CMs fulfill the criteria for anti-tumor drugs. In this paper, we review the efficacy of 14 Chinese herbal medicines, across a wide range applications, and discuss their effects on caspase-3 activity in tumor cells.