彩色多普勒超声对中孕期胎鼠心肌细胞凋亡的影响及其远期效应

Influences and remote effects of color Doppler ultrasound on myocardial cell apoptosis of fetal rats

目的:探讨彩色多普勒超声照射对中孕期胎鼠心肌细胞凋亡的影响及其远期效应,从而为彩色多普勒超声临床安全应用提供实验依据。方法:将24只孕14dSD大鼠按取材时间不同随机等分为胚胎组和幼仔组,再各自等分为照射30min组和对照组。胚胎组于照射后24h剖宫取胎鼠心肌标本,幼仔组于出生后10d取材。HE染色光镜观察组织细胞结构,TUNEL法检测凋亡细胞,激光共聚焦显微图像分析仪检测荧光强度,透射电镜观察超微结构的变化。结果:各组光镜下观察未见心肌组织细胞结构异常;TUNEL法检测结果,胚胎对照组心肌组织内可见散在凋亡细胞,幼仔各组心肌组织内凋亡细胞则更稀少;胚胎照射30min组凋亡细胞较易观察到,部分区域可见较密集的凋亡细胞。胚胎照射30min组犤(0.48±0.42)IU犦与胚胎对照组荧光强度犤(4.08±0.54)IU犦比较,差异有显著性意义(t=2.45,P<0.05);幼仔照射30min组和幼仔对照组荧光强度差异无显著性意义(P>0.05)。胚胎照射30min组心肌电镜检查发现染色质浓缩边集、线粒体、内质网肿胀等超微结构变化。结论:彩色多普勒超声照射30min以上可引起中孕胎鼠心肌细胞凋亡,但这种影响在幼仔期消失。

AIM:To investigate the influences and remote effects of irradiation with color Doppler ultrasound(CDUS) myocardial cell apoptosis of fetal rats so as to provide an experimental evidence for clinical safe application of CDUS. METHODS:Twenty-four 14-day pregnant Spraque-Danles rats were divided into fetal group and neonatal group according to the sample-drawing time randomly and averagely,and each group was subdivided into control group and 30-minute irradiation group.The fetal rats' myocardial samples were removed 24 hours after irradiation in the embryo group and the neonatal rats' were removed 10 days after birth.Structure of histocyte was observed by hematoxylin and eosin(HE) staining electron microscope;Apoptosis cells were detected with the method of terminal deoxynucleotidyl transferase-mediated D-UTP nick end labeling(TUNEL);Fluorescent intensity was measured with laser focus microimaging analysis apparatus;Ultrastructural changes were observed with transmission electron microscope. RESULTS:There were no abnormal changes in myocardial cell structure among all groups under light microscope.TUNEL results showed that myocardial tissues were seen in diffused apoptostic cells separately in the embryo control group,and apoptostic cells in myocardial tissues were even less in neonatal rats of all groups. Apoptostic cells were easily to be observed after 30-minute embryo irradiation, and intensive ones were seen in partial area. Difference fluorescent intensity between embryo irradiation group[(0.48±0.42) IU] and control group[(4.08±0.54) IU]had significant meaning(t=2.45,P< 0.05); while differences of them between neonatal irradiation group and control group had no significant meaning(P >0.05). Supermicro structural changes as margination of chromatin,mitochondrion, swelling of endoplasmic reticulum etc.were found under myocardial electron microscope after 30-minute irradiation. CONCLUSION:Continuous irradiation over 30 minutes by CDUS may result in myocardium cell apoptosis in fetal rats,but this phenomenon will disappear after birth.