The Effects Of TGF-β3、BMP4and Histone H3Acetylation In Fetal Cleft Palate Induced By2,3,7,8-tetrachlorodibenzo-P-dioxin

Part Ⅰ The expression of TGF-β3, BMP4mRNA in TCDD-inducedcleft palate in fetal miceObjective: Research on pregnant mice of C57BL/6J induced fetalmice cleft palate by2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) atoptimal induction dose, the expression of transforming growth factor-beta3(TGF-β3) and bone morphogenetic protein4(BMP4) mRNA in palataltissue, and to explore the possible mechanism of which.Methods:10pregnant mice were randomly divided into TCDD group(n=5)and control group (n=5), On gestation day10(GD10), the mice inthe treated group received intragastric administration with TCDD28μg/kg,while the mice in the control group received equivalent corn oil; thepregnant mice were sacrificed on the GD16.5, gross anatomy morphologyobservation, at same time, with4%paraformaldehyde fetal head, HEstained histological observation. Another C57BL/6J pregnant mice (36)were randomly divided into TCDD group (18) and the control group (18), Were taken in each group GD13.5, GD14.5and GD15.5fetal palatal(processing methods as the former), total RNA was extracted tissue usingQ-PCR technique to detect fetal mice in each group TGF-β3, BMP4mRNA expression levels.Results: In GD16.5, TCDD group appeared fetal cleft palate, controlgroup completely normal. TGF-β3in GD13.5, GD14.5, GD15.5mRNAexpression in the control group were0.7720±0.1548,0.8373±0.2458,0.9475±0.1737, TCDD group were1.0948±0.1733,1.1624±0.1892,1.0482±0.3438, TCDD group GD13.5, GD14.5higher, the difference wasstatistically significant (p<0.01, p<0.05), in GD15.5also higher, thedifference was not statistically significant (p>0.05). BMP4in GD13.5,GD14.5, GD15.5mRNA expression in the control group were0.8470±0.2168,1.0531±0.0178,0.6865±0.1436, TCDD group was1.1114±0.0587,0.8617±0.0780,0.5825±0.1614, TCDD group GD13.5, GD14.5difference was statistically significant (p<0.05, p<0.01), in GD15.5nosignificant difference (p>0.05).Conclusion: TCDD can induced C57BL/6J fetal cleft palate stable,meanwhile, it allows gene TGF-β3, BMP4mRNA expression levelsoccurred significantly changed. Part Ⅱ The role of histone H3acetylation on cleft palate in miceinduced by2,3,7,8-tetrachlorodibenzo-p-dioxinObjective: To explore the possible role of histone H3acetylation incleft palate induced by2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) inC57BL/6J mice, and its possible mechanism.Methods: On gestation day10(GD10),18pregnant mice wererandomly divided into two groups as the treated group and the controlgroup with9mice in each group. The mice in the treated group receivedintragastric administration with TCDD28μg/kg, while the mice in thecontrol group received equivalent corn oil. The pregnant mice weresacrificed on GD13.5, GD14.5and GD15.5. Fetal palates were collectedand nucleoproteins were extracted, determined the activities of histoneacetyltransferases (HATs) by Colorimetric. Besides, another18pregnantmice were randomly divided into treated group and control group(grouping and processing methods as the former), the nucleoproteins wereextracted at the above time point, the expression level of acetylated histoneH3(Ac-H3) was detected by Western-blot in the mice palate.Results: The activities of HATs was0.4097±0.0147,0.5223±0.01709and0.6435±0.0139in control group on GD13.5, GD14.5andGD15.5;0.8650±0.0129,0.7191±0.0178and0.5512±0.0168in TCDDgroup. The activities of HATs in TCDD group were higher than control group on GD13.5, GD14.5, the differences were statistically significant(t=-56.932, t=-19.516, P<0.01); however, the activities of HATs in TCDDgroup was lower than control group on GD15.5, between the two groupswas statistically significant (t=10.382, P<0.01). The expression levels ofAc-H3were0.7450±0.1135,1.0559±0.2494and1.7955±0.0819incontrol group; on the same time,1.4490±0.1460,1.6418±0.0997and1.5121±0.1502in TCDD group. The expression of Ac-H3in TCDDgroup were higher than control group on GD13.5, GD14.5, the differenceswere statistically significant (t=-6.593,-3.779, P<0.01, P <0.05); however,the expression of Ac-H3in TCDD group was lower than control group onGD15.5, between the two groups were statistically significant (t=2.870,P<0.05).Conclusion: The acetylation of histone H3involved in the cleft palateof C57BL/6J mice induced by TCDD, it may be one mechanism ofTCDD-induced cleft palate.