| In this experiment the effects of Baicalin--one active ingredient of Scutellaria baicalensis Georgi on mouse uterus micro-environment during implantation were studied. The protective mechanism of Baicalin on implantation mice uterus was investigated by detection of Th1/Th2 cytokines and Nitric oxide synthatase (NOS) activity.In vivo, lipopolysaccharide (LPS) was used as inducible drug to establish a model that embryo implantation was hindered. The pregnant mice were divided into 6 groups: control group, sterile saline group and LPS groups (0.001, 0.002, 0.004, 0.006mg). The drugs were given by intraperitoneal injection on 3d of gestation. The contents of IFN-γ, IL-10 and NOS activity were detected on 4.5d of pregnancy. Implantation embryo number was observed at 6.5d of gestation. The results showed that the abortive rate in 0.004mg LPS group was 75%, and their implantated embryo number were significantly lower (P <0.01) than those in the control group. NOS activity in LPS group increased, Th1/Th2 balance tended to Th1 response, so the uterus micro-environment was not available to embryo implantation. Therefore 0.004mg LPS was used to the following experiment. Scutellaria has an important impact on cytokine balance during pregnancy, but there were less data about the tocolysis effect of its monomeric composition. Baicalin--the flavonoid ingredient of Scutellaria was used to against implantation failure induced by LPS and its protective mechanism was explored. The mice were divided into six groups, group A was the control, group B was LPS models, the mice in groups C-E were treated with gradient dose of Baicalin. In groups B-E LPS injected intraperitoneally at day 3 of gestation, administered orally distilled water and gradient dose of Baicalin at day 0.5-3.5 of gestation respectively. The sample collection was the same as above. The results showed that the implanted embryos and implantation rate in Baicalin group were higher than those in model group. NOS and IFN-γactivity of serum and uterine tissue in Balcalin groups decreased, IL-10 levels increased. Compare with the model group, there were significantly different (P <0.05 or P <0.01), particularly in 0.5mg Baicalin group.In vitro, the endometrial cells of 4.5d gestation mice were obtained successfully by 0.25% trypsin-EDTA digestion. Different concentrations of LPS/Baicalin treated the endometrial cells at logarithmic phase, the cell viability was conducted by MTT assay to select suitable concentrations: 100ng/mL LPS, and 40μg/mL, 400μg/mL, 800μg/mL Baicalin. The cells grew well at logarithmic phase in 24-well plate were divided into five groups (control group, LPS interference group, three doses of Baicalin + LPS groups), the cell culture supernatants were collected at 48h and 72h to detect IFN-γ, IL-10 contents and NOS activity. The results showed, compare with the control group, NOS activity and IFN-γincreased significantly in LPS group (P<0.01); both of them in Baicalin groups decreased and reached to normal levels gradually. But IL-10 contents either in LPS or Baicalin groups had no apparent changeIn conclusion, the interfering implantation of LPS was by affecting NO synthesis and Th1/Th2 balance, and Baicalin resisted this effect through reducing NO levels in uterine tissue and peripheral blood, regulating Th2 response dominanted in Th1/Th2 balance at the same time. In vivo, Baicalin regulated Th1/Th2 balance through two hands: Increase IL-10 level of Th2 cytokine and reduce IFN-γlevel of Th1 cytokine, so the immune balance of Th1/Th2 tended to Th2 that was beneficial to pregnancy. However, in vitro the results showed that Baicalin had no significant effects on IL-10 secretion of cultured endometrial cells, Baicalin played a role as plant estrogen in vivo to affect neuro-endocrine axis that caused the secretion of IL-10 changed during pregnancy.
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