组蛋白H3乙酰化在TCDD致胎鼠腭裂发生中的作用

The role of histone H3 acetylation on cleft palate in mice induced by 2, 3, 7, 8-tetrachlorodibenzop-dioxin

目的 探讨组蛋白H3乙酰化在2,3,7,8-四氯二苯二噁英（2,3,7,8-tetrachlorodibenzo-p-dioxin,TCDD）所致的C57 BL/6J胎鼠腭裂畸形发生中的作用及其机制.方法 共36只C57BL/6J孕鼠,将18只随机分为TCDD组和对照组,每组9只,TCDD组于受孕后第10天（gestation day,GD10）以TCDD 28 μg/kg灌胃1次;对照组于GD10以等量玉米油灌胃;分别于GD13.5、GD14.5及GD15.5处死孕鼠,收集胎鼠的上腭组织提取核蛋白,用比色法检测组蛋白乙酰转移化酶（histone acetyltransferases,HATs）活性.另18只孕鼠随机分为TCDD组和对照组（分组及各组只数同前）,分别在上述时间点提取核蛋白,用Western-blot方法检测乙酰化的组蛋白H3（acetylated histone H3,Ac-H3）在上腭的表达情况.结果 各个时间点HATs相对活性在GD13.5,GD14.5、GD15.5所测吸光度A值对照组分别为0.4097±0.0147、0.5223±0.017 1和0.643 5±0.0139,TCDD组分别为0.8650±0.0129,0.719 1±0.0178和0.551 2±0.016 8;TCDD组HATs活性在GD13.5、GD14.5分别高于对照组,差异有统计学意义（P＜0.01）;而在GD15.5 TCDD组HATs活性低于对照组,差异有统计学意义（P＜0.01）.各个时间点Ac-H3相对表达量在GD13.5,GD14.5、GD15.5,对照组分别为0.745 0±0.113 5,1.055 9±0.249 4和1.795 5±0.081 9,TCDD组分别为1.4490±0.1460,1.6418±0.0997和1.512 l±0.1502; TCDD组Ac-H3表达在GD13.5、GD14.5分别高于对照组GD13.5、GD14.5,差异均有统计学意义（P＜O.01,P＜0.05）;而在GD15.5,TCDD组Ac-H3表达低于对照组,差异有统计学意义（P＜0.05）.结论 组蛋白H3酰化参与了TCDD所致的C57BL/6J胎鼠腭裂的发生,可能是TCDD诱导腭裂发生的机制之一.

Objective To explore the role of histone H3 acetylation in cleft palate induced by 2,3,7,8-Tetrachlorodibenzo-p-dioxin （TCDD） in C57BL/6J mice,and its mechanism.Methods On gestation day 10 （GD10）,36 pregnant mice were randomly divided into two groups as the treated group（n =18） and the control group （n =18）.The mice in the treated group received intragastric administration with TCDD 28 μg/kg,while the mice in the control group received equivalent corn oil.The pregnant mice were sacrificed on GD13.5,GD14.5 and GD15.5,collecting fetal palates to determine the activities of histone acetyltransferases （HATs） by Colorimetric and the expression level of acetylated histone H3 （Acetylated histone H3,Ac-H3） by Western-blot.Results The activity of HATs was 0.409 7 ± 0.0147,0.522 3 ± 0.017 1 and 0.643 5 ± 0.013 9 in control group on GD13.5,GD14.5 and GD15.5; 0.8650 ± 0.0129,0.719 1 ± 0.0178 and0.5512 ± 0.016 8 in TCDD group.The activity of HATs in TCDD group was higher than that in control group on GD13.5,GD14.5,showing significantly difference between the two groups （t =-56.932,t =-19.516,P 〈 0.01） ; however,the activity of HATs in TCDD group was significantly lower than that in control group on GD15.5 （t =10.382,P 〈 0.01）.The expression level of Ac-H3 was 0.745 0 ± 0.113 5,1.055 9 ± 0.249 4 and 1.795 5 ± 0.0819 in control group on GD13.5,GD14.5 andGD15.5; while 1.4490 ± 0.1460,1.641 8 ± 0.099 7 and 1.512 1 ± 0.150 2 in TCDD group.The expression of Ac-H3 in TCDD group was higher than that in control group on GD13.5,GD14.5,showing significantly difference（t =-6.593,-3.779,P 〈 0.01,P 〈 0.05） ; However,the expression of Ac-H3 in TCDD group was statistically lower than that in control group （t =2.870,P 〈 0.05）.Conclusion The acetylation of histone H3 was involved in the cleft palate of C57BL/6J mice induced by TCDD,which may be one of the mechanisms in TCDD-induced cleft palate.