[Noise magnetic fields mitigates the inhibition of secretion function of primary human villous trophoblasts induced by 50 Hz magnetic fields].

OBJECTIVE: To explore the effects of 50 Hz sinusoidal magnetic fields (MF) on secretion function of primary human villous trophoblasts in vitro, and the interference effect of "noise" MF. METHODS: The trophoblasts were isolated from human villus by trypsin digestion and incubated in DMEM medium.Then the trophoblasts were exposed to 0.4 mT 50 Hz MF and/or "noise" MF respectively for different durations. Each exposure group was matched with one control group which was from the same villus and cultured with the same condition except the MF exposure. The concentrations of human chorionic gonadotropin (HCG) and progesterone in the culture medium were measured by immunofluorescence. Statistical significance of differences between means was determined by one way-ANOVA with P<0.05 considered significant. RESULT: 50 Hz MF inhibited the HCG and progesterone secretion significantly when exposure for 72 h (compared with control group, P<0.05). There was no significant change of HCG and progesterone secretion when trophoblasts were exposed to 0.4 mT "noise" MF within 72 h (compared with control group, P>0.05). However, by superimposing the "noise" MF, the inhibition of HCG and progesterone secretion of trophoblasts induced by 50 Hz MF was eliminated. CONCLUSION: The exposure to 50 Hz MF for long period could inhibit trophoblasts secreting HCG and progesterone, and the "noise" MF with the same intensity could eliminate the effects induced by 50 Hz MF.

[Effects of 50 Hz magnetic fields exposure on secretion of primary human villous trophoblasts].

OBJECTIVE: To explore the possible effects of 50 Hz magnetic fields (MF) exposure on HCG and progesterone secretion of human villous trophoblasts in vitro. METHODS: The trophoblasts were isolated from human villus by trypsin digestion and incubated in DMEM medium. Then the trophoblasts were exposed to 0.2 mT, 0.4 mT 50 Hz MF for 6 h, 12 h, 24 h, 48 h and 72 h, respectively. Each exposure group was matched to one control group which was from the same villus and cultured with the same condition except the 50 Hz MF exposure. The concentration of human chorionic gonadotropin (HCG) and progesterone in the culture medium was detected by electrochemiluminescence immunoassay. Statistical significance of differences between means was determined by one way-ANOVA with P < 0.05 considered significant. RESULTS: Exposure of trophoblasts to 50 Hz MF at 0.2 mT intensity within 72 h did not affect the secretion level of HCG and progesterone (compared with blank control, P > 0.05). There was also no significant change of the secretion level of HCG and progesterone when trophoblasts were exposed to 0.4 mT 50 Hz MF within 48 h (compared with blank control, P > 0.05). However, 50 Hz MF inhibited the HCG and progesterone secretion significantly with exposure for 72 h (compared with blank control, P < 0.05). CONCLUSION: The exposure to 50 Hz MF for long period could inhibit trophoblasts excreting the HCG and progesterone, and the threshold intensity may be between 0.2 mT and 0.4 mT.

[Apoptosis-related gene expression of human villous trophoblasts exposed to 50 Hz magnetic field].

OBJECTIVE: To study apoptosis-related gene expression of human villous trophoblasts exposed to 50 Hz magnetic field and to investigate the possible mechanism of human reproductive health effects caused by 50 Hz magnetic field. METHODS: Cultured human villous trophoblasts were exposed to 50 Hz magnetic field at 0.4 mT for 6, 48, 72 hours. Gene expressions of Bcl-2, Bax, Caspase-3, p53 and Fas were analyzed using real-time reverse transcription polymerase chain reaction (RT-PCR) assay. RESULTS: Within 72 hours, the average fold change for each gene was near 1.00, and there was no significant difference on expression pattern in each gene between exposure and control groups (P > 0.05). CONCLUSION: 0.4 mT 50 Hz magnetic field does not affect the apoptosis-related gene expression of human villous trophoblasts in vitro.

[Effect of Tongxinluo superfine on experimental anginal model (contraction of collaterals) in rat with endothelial dysfunction].

OBJECTIVE: To study the effect of Tongxinluo superfine (TXL) on experimental anginal model induced by Arginine Vasopressin in rats with endothelial dysfunction. METHOD: First, the endothelial dysfunction rat model was made by methionine-induced hyperhomocysteinemia (HHcy). The thoracic aorta were excised, and acetylcholine (Ach)-induced endothelium dependent relaxation and sodium nitroprusside (SNP) induced endothelium-independent relaxation were measured. Total plasma homocysteine (Hcy) concentrations were measured with automated fluorescence polarization immunoassay (FPIA). Enzyme-linked immunosorbent assay (ELISA) was used to detect plasma von Willebrand factor (vWF) level. Plasma nitric oxide (NO) contents were assayed by method of nitrate reductase. Then, the rat model of collaterals contraction (model group) was established by AVP intravenous injection in rats with endothelial dysfunction and the S wave change (DeltaS) and T wave depression in Lead II ECG were used as the index of angina severity. The nitric oxide (NO) contents in serum and the expression of myocardium eNOS mRNA were measured. RESULT: Ach (0. 1-1000 nmol L(-1))-induced endothelium dependent relaxation (EDR) of aortic rings was significantly decreased in HHcy group. The endothelium-independent relaxation induced by SNP (0.001-10 micromol L(-1)) was not significantly different between the two groups. Plasma homocysteine concentrations and vWF levels in rats treated with methionine were higher than those of control group, while NO contents were significantly decreased in HHcy group compared with control. The results showed that L-methionine intake induced hyperhomocysteinemia in rats. Impaired EDR, increased vWF and decreased NO suggested the exist of endothelial dysfunction. DeltaS of model group increased from 1 min to 5 min and T wave of model group depressed at 2 min compared with that of control after the administration of vasopressin (0.5 U kg(-1)). The intragastric administration of TXL inhibited vasopressin-induced S wave change at 4 min and 5 min and T wave depression from 30 s to 3 min after AVP injection. The NO contents in serum and the expression of myocardium eNOS mRNA of TXL group were increased compared with model group. CONCLUSION: Experimental angina induced by AVP injection is more severe in rats with endothelial dysfunction. Tongxinluo Superfine can protect against collaterals contraction in rats maybe by increasing the NO contents in serum and the expression of myocardium eNOS mRNA.

[Study on sini decoction in treatment of intestinal ischemia-reperfusion injury in rats: mechanism relating to oxygen radical and bcl-2 protein].

OBJECTIVE: To investigate the protective effect of Sini decoction (SND) on intestinal mucosa in rats with intestinal ischemia reperfusion (I/R) and the mechanism relating to oxygen radical and Bcl-2 protein expression. METHOD: Thirty-two SD rats of both sexes were randomly divided into 4 equal groups: (1) control group in which sham operation was performed; (2) model group in which intestinal I/R was produced by clamping super mesenteric artery(SMA) for 1 hour and declamping SMA for 3 hours; (3) SND low dose group in which SND(3 g x kg(-1) x d(-1)) was given via stomach tube for 3 days before operation; (4) SND high dose group in which SND(6 g x kg(-1) x d(1)) was given via stomach tube, for 3 days before operation. A strip of small intestine was taken from distal end of ileum for light microscopic examination, Chiu's score and the detection of intestinal water content (IWC). Apoptosis of intestinal mucosa cell was examined by TUNEL method. Superoxide dismutase (SOD) activity, malondisldehyde (MDA) concentration of intestinal mucosa were detected. The protein express of Bcl-2 of intestinal mucosa was analyzed by immunochemistory. RESULT: Intestinal /R resulted in histopathological changes in intestinal mucosa, increased Chiu's scores, apoptosis index, IWC and MDA content, and reduced SOD activity and the protein expression of Bcl-2 significantly (P < 0.01). The pretreatment of SND could attenuate the above changes significantly (P < 0.01), but there was no significant difference for the above variables between SND low dose group and SND high dose group (P > 0.05). Apoptosis index was significantly negatively correlative to SOD activity in model group and two SND groups. There were significantly negative correlation between apoptosis index and protein expression of Bcl-2 in model group and SND low dose group. CONCLUSION: SND can attenuate intestinal mucosa injury following intestinal U/R, which is related to reducing intestinal mucosa cell apoptosis by removing oxygen free radical and upregulating the protein expression of Bcl-2.

[Expression of aquaporin 2, a water channel, in human endometrium during the menstrual cycle].

OBJECTIVE: To examine the expression of aquaporin 2 (AQP2) in human endometrium. METHODS: Specimens of human endometrium were collected from 87 women at different menstrual cycles, aged 30 +/- 3, 23 cases in the proliferative phase, 30 cases in the early secretory phase and 34 cases in the mid-secretory phase respectively. Immunohistochemistry and Western blotting were utilized to detect the localization and expression of AQP2 in the endometrium. Reverse transcription-polymerase chain reaction (RT-PCR) was employed to detect its messenger RNA. The PCR product was cloned and sequenced. RESULTS: Positive immunoreactivity of AQP2 was found in the epithelia cells and glandular epithelial cells of all specimens of human endometrium at different phases of the menstrual cycle, and all stromal cells were not stained. The reactive substance was primarily distributed in the membrane and cytoplasm, but not in the nuclei of all positive cells. In Western blotting showed dominant bands with relative molecular weight between 35,000 Da and 50,000 Da, which was corresponded to the glycosylated form of AQP2 by the positive control from rat kidney. Semi-quantitative analysis showed that the relative expression of AQP2 in the mid-secretory phase was 1.63 +/- 0.15, significantly higher than those in the early secretory phase (1.33 +/- 0.14, P < 0.05) and that in the proliferative phase (1.03 +/- 0.10, P < 0.01). Message RNA was found out in all cases by RT-PCR and the PCR product was confirmed in nearly exact (99%) consistency with the GenBank by sequencing. AQP2 mRNA was expressed in all normal endometrium at different phases, and was weakly expressed in the endometrium at the proliferative phase. Sequencing showed that the AQP2 sequence was 99% homologous with that in the GenBank. CONCLUSION: AQP2 expression in the human endometrium suggests that AQP2 may be involved in the regulation of uterine fluid homeostasis influenced by ovarian steroid hormones in the menstrual cycle.

Relationship between inactivation of p16 gene and gastric carcinoma.

AIM: To investigate the relationship between inactivation of p16 gene and gastric carcinoma, and the mechanism of inactivation of p16 gene in gastric carcinogenesis. METHODS: 40 fresh tumor tissue specimens were taken from primary gastric cancer patients. Expression of P16 protein was detected by immunohistochemical method. Deletion and point mutation of p16 gene were analyzed by polymerase chain reaction (PCR) and DNA sequencing, respectively. RESULTS: The frequency of loss of P16 protein expression in the gastric cancer tissue, adjacent nontumor tissue, and distal normal tissue was 77.5 % (31/40), 55.0 % (22/40), and 17.5 % (7/40), respectively (P<0.005). Homozygous deletion of exon 1 and exon 3 was observed in two and three cases, respectively, giving an overall frequency of homozygous deletion of 12.5 %. All five cases had diffuse type gastric carcinoma. No p16 gene point mutation was detected. CONCLUSION: These findings suggest a close correlation between inactivation of p16 gene and gastric carcinoma. Further investigations are needed to testify the mechanism of inactivation of p16 gene in gastric carcinogenesis.

[Experimental study on effect of sini decoction on myocardial endothelin in myocardial ischemic rats].

OBJECTIVE: To study the molecular mechanism of effect of Sini Decoction (SND) on myocardial endothelin (MET) in myocardial ischemic rats. METHODS: Sprague-Dawley rats were randomly divided into 3 groups, the normal control group, the ischemia group and the SND group. Myocardial ischemia was produced by pituitrin in the latter two groups. The content, immunohistochemical assay and gene expression of MET-1 were determined in all the three groups and compared. RESULTS: The content of MET in the SND group was significantly lower than that in the ischemia group (P < 0.01). Immunohistochemical examination showed that MET-1 was mainly located at the cardiac muscle cells and vascular endothelial cells with the grey scale obviously lower in the ischemia group than that in the control group and the SND group (P < 0.01). While RT-PCR showed that the grey scale of PCR product band in the ischemia group was significantly higher than that in the other two groups (P < 0.01). CONCLUSION: SND could significantly lower MET content, it may be related to the effect of SND in inhibiting MET-1 gene expression and protein synthesis.