低频超声抗兔妊娠对胎盘组织细胞Bax mRNA、Bcl-2 mRNA的影响

Bax mRNA and Bcl-2 mRNA expression in the placenta of rabbit after exposuring to low frequency ultrasonic

目的:探讨低频超声终止妊娠的可能性并观察低频超声对兔胎盘组织细胞Bax mRNA、Bc l-2 mRNA表达的影响。方法:利用低频聚焦声束超声(353 kHz“超声终止早孕治疗机”样机)6种声强各90 s体内直接照射妊娠第10天兔胚胎,妊娠20天时观察各组胚胎死亡率;选用完全抗孕剂量(40 W/cm2×90 s)照射胚胎,照后24、48、72、96、120、168、192 h留取胎盘,原位杂交技术检测各组BaxmRNA、Bc l-2 mRNA表达情况。结果:对照组胚胎总死亡率为11.36%(30/264);照射组中声强25 W/cm2、30 W/cm2及≥35 W/cm2组的胚胎死亡率分别为24.49%(12/49)、71.15%(37/52)和100.00%(62/62、45/45、40/40、35/35)。超声辐照胚胎后24 h胎盘组织细胞表达Bax mRNA增加,96 h增加最明显,120 h表达下降,192 h恢复至对照组水平;Bc l-2 mRNA表达趋势与Bax mRNA表达相反:照射后24 h开始下降,96 h下降至最低点,120 h开始恢复,照后192 h接近对照组水平。结论:低频超声抗早孕具有潜在的可行性,低频超声辐照胚胎可诱导胎盘组织细胞Bax mRNA表达增加,Bc l-2 mRNA表达下降,从而诱导胎盘组织细胞凋亡增加,但具有一定的可复性。

Objective; To investigate the availability of early pregnancy termination with low frequency ultrasonic and to investigate the role of Bax mRNA and Bcl -2 mRNA expression in the placenta of rabbit after low frequency ultrasound irradiation. Methods： The implantation sites of left uterus of 10th day rabbit embryos were expesured with an intensity of 25 W/cm^2×90s, 30 W/cm^2×90s, 35 W/cm^2×90 s, 40 W/cm^2×90 s, 45 W/cm^2×90 s 和 50 W/cm^2×90 s. At same time, the embryos of right uterus belonged to the control group. At 20th day of gestation, the animals were sacrificed. Embryonic mortality was observed. The embryos were irradiated with an intensity of totally contragestion （40 W/cm^2×90 s ） . The expression of Bax mRNA and Bcl -2 mRNA of placenta cells were tested with in situ hybridization at 24, 48, 72, 96, 120, 168, 192 hours after irradiating. Results： It was found that the embryonic mortality of experimental group were 24. 49 % （12/49）, 71.15 % （37/52） and 100% （63/62, 45/45, 40/40, 35/35 ）respectably with an intensity of 25 W/ cm^2, 30 W/cm^2 and equal or more than 35W/cm^2. The incidence of Bax mRNA expression of placenta cell was increased at 24 hours after irradiating and peaked at 96 hours, but then decreased gradually, and recovered to control levels by 192 hours. Otherwise, the incidence of Bcl -2 mRNA expression of placenta cell was decreased at 24 hours after irradiating and least at 96 hours, but then increased gradually, and recovered to control levels by 192 hours. Conclusion： The result proves that it is feasible for early pregnancy termination of rabbit with low frequency ultrasonic. The low frequency ultrasonic may result in more Bax mRNA expression of placenta cell and less Bcl - 2 mRNA expression. That might result in more apoptosis in placenta cells.