Progress in the role of endometrial glucose metabolism in embryo implantation / 生理学报

The synthesis and decomposition of glycogen adjust the blood glucose dynamically to maintain the energy supply required by the cells. As the only hormone that lowers blood sugar in the body, insulin can promote glycogen synthesis by activating the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway and increasing glucose transporter translocation, and inhibit gluconeogenesis to lower blood glucose. In the endometrium, glycogen metabolism is active, but gluconeogenesis does not occur. The glycogen metabolism in the endometrium is controlled not only by the classical glucose regulating hormones, but also by the ovarian hormones. The functional activities related to implantation of the endometrium during the implantation window require glucose as energy source. A large amount of glucose is used to synthesize glycogen in the endometrium before implantation, which could meet the increased energy demand for embryo implantation. In diabetes, glycogen metabolism in the endometrium is impaired, which frequently leads to implantation failure and early abortion. This article reviews the glycogen metabolism in the endometrium and discusses its role in embryo implantation, which provide new ideas for embryo implantation research and infertility treatment.

Progress of non-genomic action of estrogen and its impact on female reproduction / 生理学报

Estrogen is one of the steroid hormones. Besides the genomic action mediated by its intracellular receptor on target cells, there is now increasing body of evidence indicating that estrogen also has non-genomic action. For the non-genomic action, estrogen binds to its receptor on cell membrane, subsequently rapidly activates various intracellular signaling pathways, such as PLC/Ca(2+), ERK/MAPK, cAMP-PKA, PI3K-AKT-NOS, and finally induces biological effects. The non-genomic effects of estrogen on physiologic and pathologic processes have been found in many tissues within the reproductive, nervous and cardiovascular systems and bone etc. In reproductive system, it has been demonstrated that estrogen plays important roles in follicle development, fertilization and embryo implantation, and it is involved in the genesis and development of genital tract tumors and breast cancer. In this review, we focus on the general characteristics of non-genomic action of estrogen, its main nonnuclear signaling pathways and physiological and pathological significance, especially its influences in female reproductive functions.

Progesterone-induced microRNA-1a inhibits the proliferation of endometrial epithelial cells / 生理学报

The aim of the present study was to investigate the effects of progesterone (P4)-induced microRNA-1a (miR-1a) on the proliferation of endometrial epithelial cells (EECs) and the underlying mechanism. In vivo, following subcutaneous injection of estradiol (E2) alone (E2 group) or combined injections of E2 and P4 (E2P4 group) in ovariectomized mice, quantitative real-time PCR (qPCR) was used to check the expression of miR-1a-3p in the directly isolated mouse EECs. The agomir or antagomir specific for miR-1a-3p was injected into one side of the uterine horns of ovariectomized mice pretreated with E2 alone or in combination with P4, and the non-specific control agomir or antagomir was injected into their contralateral horns. Flow cytometry was used to analyze the cell cycle of EECs. Immunohistochemistry (IHC) was used to examine the location and expression of cyclin D2, cyclin E1, and cyclin E2 in the uterine tissue sections. In vitro, primary cultured mouse EECs were pretreated with E2 alone (E2 group) or in combination with P4 (E2P4 group). qPCR was used to detect the expression of miR-1a-3p. Exogenous mimic of miR-1a-3p was transfected into E2-pretreated EECs, and EdU incorporation analysis was used to test the proliferation activity of the EECs. The result of in vivo experiment showed that the expression of miR-1a-3p in E2P4 group was significantly higher than that in E2 group (P < 0.05). The miR-1a-3p agomir arrested cell cycle at G1 to S transition in the mice injected subcutaneously with E2 alone (P < 0.05). Conversely, silencing of miR-1a-3p with transfection of miR-1a-3p antagomir promoted the entry of cells into S phase in the mice injected subcutaneously with both E2 and P4 (P < 0.05). The expressions of cyclin E1 and cyclin E2, except for cyclin D2, in uterine sections were also dramatically reduced by miR-1a-3p overexpression in the uterine epithelium (P < 0.05). In vitro, miR-1a-3p was not expressed in the cells of both E2 and E2P4 groups. The mimic of miR-1a-3p decreased EECs proliferation activity (P < 0.05). These results indicate that P4-induced miR-1a can inhibit the expression of cyclin E1 and cyclin E2, consequently suppressing the proliferation of mouse EECs by arresting cells at G1/S phase.

Protective effect of breviscapine on cardiac function in children after cardiopulmonary bypass undergoing open heart surgery / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To assess the condition of myocardial injury after cardiopulmonary bypass (CPB) and the effects of breviscapine (BVC) on cardiac function in children undergoing open heart surgery.</p><p><b>METHODS</b>Thirty-six children (ASA II or III, aged 2-65 months) scheduled to receive ventricular septal defect repairing were randomly assigned to three groups, the control group treated with saline, and the BVC treated groups treated respectively with low dose (0.5 mg/kg) and high dose (1.0 mg/kg) BVC, 12 patients in each group. Saline or BVC (in volume of 15 mL) was administered intravenously after induction of anesthesia with micro-pump within 30 min. Blood levels of troponin I (cTn-I ) and malondialdehyde (MDA) were measured at different time points: pre-operation (T0), during aortic unclamping (T1), and 30 min, 1 h, 6 h, 24 h after aortic unclamping (T2, T3, T4, T5). And the time of operation, CPB, aortic unclamping, and the condition of drainage in 24 h after operation as well as the dosages of narcotics (midazolam, propofol and fentanyl) used were recorded.</p><p><b>RESULTS</b>No significant difference among groups was found in terms of sex ratio, age, body weight, time of aortic unclamping, CPB and operation, as well as the dosages of narcotics used and the volume of post-operation drainage. Compared with baseline (T0), levels of cTn-I at T1, T4 and T5 increased significantly in all three groups (P<0.01), with the peak revealed at T4; cTn-I in the control group were higher than those in the low dose BVC treated group at T1 and T4 (P<0.01), and those in the high dose BVC group at T1, T4, and T5, while it was insignificantly different between the two BVC treated groups. Level of plasmal MDA began to rise in all groups at T1 with the peak revealed at T2, it lowered after then, and reached the baseline at T5; comparison between groups showed that it was lower in the BVC treated groups than in the control group at T1-T4.</p><p><b>CONCLUSIONS</b>Different degree of cardiac injury always happens after open heart surgery and CPB, showing high level of cTn- I within 24 h with the peak revealed at 6 h after aortic unclamping. Intravenous perfusion BVC before CPB at the dose of 0.5 or 1 mg/kg could protect the cardiac function to some extent.</p>

Nongenomic action and mechanism of 17β-estradiol in cytosolic calcium concentration in delayed implantation mouse endometrial stromal cells / 生理学报

To investigate the existence of nongenomic action of 17β-estradiol (E(2)) in the delayed implantation mouse endometrial stromal cells, the changes in intracellular calcium concentration ([Ca(2+)](i)) and the upstream of calcium signal in vitro were detected. The experiment was composed of two parts. Firstly, the change in [Ca(2+)](i) in endometrial stromal cells induced by E(2) under different conditions was detected. The mice were divided into 6 groups as follows: 0.1% dimethylsulfoxide (DMSO) control group, 1×10(-8) mol/L bovine serum albumin (BSA) control group, 1×10(-8) mol/L E(2) group, 1×10(-8) mol/L E(2) conjugated with BSA (E(2)-BSA) group, 1×10(-8) mol/L E(2) + calcium-free medium group, 1×10(-8) mol/L E(2) + 5 mg/mL tamoxifen group, with 4 mice in each group. The endometrial tissue was obtained from delayed implantation mice at pregnant day 7, and digested by incubation of tissue minces in Hankos balanced salts (HBSS, pH 7.2), which contained glucose (1 g/L), and collagenase I (0.125%), for 1 h at 37 degrees C. The stromal cells were preloaded with 2.5 mmol/L Fluo-3/AM, a fluorescent probe of calcium, for 30 min. A confocal laser scanning microscope, which fixed the wave length of excitation and emission at 488 nm and 526 nm, respectively, was used to detect the change in [Ca(2+)](i). Secondly, the mechanism of E(2) effects in endometrial stromal cells was investigated. Immunofluorescent method was used to detect the change in phosphorylation of phospholipase C (PLC) before and after the stromal cells were treated with E(2) for 5 min, 15 min, and 30 min. Seven delayed implantation mice were used. The results were as follows. [Ca(2+)](i) increased immediately and reached the maximum at 15 min after the stromal cells were treated with 1×10(-8) mol/L E(2) and returned to the normal level at 30 min. In E(2)-BSA group and E(2) + calcium-free medium group the same results were obtained as that in E(2) group, but there was no increase of [Ca(2+)](i) in DMSO and BSA groups. Tamoxifen, a traditional antagonist of estrogen receptor, did not inhibit the increase in [Ca(2+)](i) induced by E(2). Immunofluorescent results showed that the change in phosphorylated-PLC level had the same trend as [Ca(2+)](i) after the cells were treated with E(2). Compared with that in the control group, the immunofluorescent intensity increased at the beginning and achieved the maximum at 15 min (P<0.001), then declined to the normal level at 30 min. These results suggest that the rapid response of [Ca(2+)](i) induced by E(2) in the endometrial stromal cells in delayed implantation mice is possibly carried out through a nongenomic pathway, and the transmembrane signal transduction is related to the phosphorylation of PLC in this process.

The progesterone-induced expression of cyclin G1 and its effect on the proliferation of mouse uterine epithelial cells / 生理学报

The aim of the present study is to investigate the effect of progesterone-induced expression of cyclin G1 on the proliferation of endometrial epithelial cells. To obtain mouse endometrial epithelial cells, the uteri were isolated from ovariectomized mice which were injected subcutaneously with 100 ng estradiol per day for two days. Then the uteri were digested by dispase and pancreatin respectively. Endometrial epithelial cells were cultured in DMEM/F12 containing 6% fetal bovine serum, and divided into four groups when they grew to confluence. Each of the groups was treated as follows: Group E was treated with 0.01 micromol/L estradiol only, group P was treated with 1 micromol/L progesterone, group EP was treated with both 0.01 micromol/L estradiol and 1 micromol/L progesterone, and group C was treated with 0.01% DMSO for control. Immunocytochemistry was used to examine the expression of cyclin G1 protein. MTT assay was used to evaluate metabolic activity of cells. Flow cytometry was used to check the number of cells distributing in each phase of the cell cycle. The result of immunocytochemistry showed that there was no expression of cyclin G1 protein in group C and group E, while cyclin G1 was obviously expressed in group P and group EP and localized in nucleus. In the MTT assay, compared with group C, the viability of group E significantly increased, while that of both group P and group EP decreased significantly. The results of flow cytometry were in accordance with those of MTT, which showed that compared with group C, group E had a higher proportion of cells in S phase, while group P, as well as group EP had a lower proportion of cells in S phase but a higher proportion in G1 phase and G2/M phase. These results indicate that progesterone could induce cyclin G1 expression in the primary culture of mouse endometrial epithelial cells, meanwhile inhibit the proliferation of cells and block the cell cycle progression. Thus, progesterone-induced expression of cyclin G1 is probably a negative factor in regulating cell cycle, which is involved in the inhibitory effect of progesterone on the proliferation of endometrial epithelial cells.

Integrins mediate the increase of concentration of intracellular free calcium in mouse eggs / 生理学报

For studying the effect of integrin on the [Ca(2+)](i) of mouse eggs and its transmembrane signaling mechanism, zona-free mouse eggs were loaded with calcium probe Fluo-3/AM and the intensity of fluorescence of the eggs treated with different factors was measured through laser confocal microscopy. The results showed that the [Ca(2+)](i) of zona-free mouse eggs was increased when the eggs were treated with RGD peptide, fibronectin (Fn) and anti-mouse integrin subunit alpha(6) and beta(1) monoclonal antibodies, respectively. The [Ca(2+)](i) of the mouse eggs was also increased when the eggs were placed in calcium-free medium and treated with RGD peptide or Fn. The changes in the mouse egg [Ca(2+)](i) caused by RGD and Fn were similar to those caused by sperm. However, the concentration of Ca(2+) of the zona-free mouse eggs pretreated with tyrosine kinase inhibitor was not increased when the eggs were treated in the same way, and, neither was the intracellular calcium increased in those eggs pretreated with PKC inhibitor when the eggs were treated with RGD peptide. It is therefore suggested that the occupancy of integrins on the membrane of mouse eggs by their ligands mediates the release of Ca(2+) and then the increase in the [Ca(2+)](i) of eggs, which is one of the early events of egg activation. The tyrosine kinase signaling pathway and PKC are involved in this process as well.