不同声强超声对孕鼠子宫收缩及胎鼠神经损伤的影响及机制

目的:探讨不同声强超声对孕鼠子宫收缩及胎鼠神经损伤的影响及机制。方法:将32只孕鼠随机分为A(0)组、B(2)组、C(4)组、D(8)组,每组各8只,分别接受声强为0 W cm~(-2)、2 W cm~(-2)、4 W cm~(-2)和8 W cm~(-2)的超声辐照20 min。记录孕鼠子宫收缩及子宫平滑肌ATP酶的活力,检测胎鼠大脑皮层与海马神经元凋亡及胆碱能神经系统相关酶的活力。结果:超声增加孕鼠子宫收缩频率、收缩幅度、收缩张力和子宫活动度(P均0.05),降低孕鼠子宫平滑肌中钠钾ATP酶、钙ATP酶和钙镁ATP酶的活性(P均0.05)。超声降低胎鼠大脑皮层和海马中Bcl~(-2)水平(P0.05),增加Bax和Caspase-3水平(P均0.05)。以及促进乙酰胆碱酯酶活力,降低乙酰胆碱和乙酰胆碱转移酶水平(P均0.05)。且4 W cm~(-2)和8 W cm~(-2)的超声比2 W cm~(-2)超声对这些指标的作用更强。结论:4 W cm~(-2)和8 W cm~(-2)超声可能通过降低ATP酶的活性促进孕鼠子宫平滑肌收缩,并可引起胎鼠大脑皮层和海马神经元损伤,机制可能与胆碱能神经元系统失衡有关,2 W cm~(-2)声强的超声对胎鼠神经元损伤甚小。

Effect and Mechanism of Different Intensity of Ultrasound on the Uterine Contraction of Pregnant Rats and the Nerve Injury of Fetal Rats

ABSTRACT Objective: To determine the effect and mechanism of ultrasound with different intensity on uterine contraction of pregnant rats and nerve injury of fetal rats. Methods: 32 pregnant rats were randomly divided into A(0) group, B(2) group, C(4) group and D(8) group, with 8 rats in each group. Rats in these groups were respectively received ultrasonic irradiation with different intensities of 0 W cm^-2, 2 W cm^-2, 4 W cm^-2 and 8 W cm^-2 for 20 min. The uterine contraction and ATPase activities of uterine smooth muscle were recorded in pregnant rats, and neuronal apoptosis and activities of cholinergic nervous system-related enzymes in cerebral cortex and hippocampus were detected in fetal rats. Results: Ultrasound increased frequency, amplitude, tension and activity of uterine contraction (P<0.05), and decreased the activities of Na⁺-K⁺ ATPase, Ca²⁺ ATPase and Ca²⁺-Mg²⁺ ATPase in uterine smooth muscle of pregnant rats (P<0.05). Ultrasound reduced Bcl-2 levels (P<0.05) and increased the levels of Bax and Caspase-3 (P<0.05) in the cerebral cortex and hippocampus of fetal rats. Ultrasound promoted acetylcholinesterase activity, and reduced acetylcholine and acetylcholine transferase levels (P<0.05). Ultrasounds with 4 W cm^-2 and 8 W cm^-2 were more effective than with 2 W cm^-2 ultrasound on the effect of these indicators. Conclusion: 4 W cm^-2 and 8 W cm^-2 might promote the contraction of uterine smooth muscle in pregnant rats through reducing the activity of ATPases, and resulting in damage to cerebral cortex and hippocampal neurons of fetal rats, the mechanism may be associated with the imbalance of the cholinergic neuron system. 2 W cm^-2 Ultrasound has little damage to fetal rat neurons.