| Objective: To study if diagnostic Color Doppler ultrasound (CDUS) could induce fetal rat's myocardial cell and intestinal epithelial cell apoptosis when rats in mid-pregnancy were irradiated beyond certain time by diagnostic CDUS, and provide new evidence of the safety of clinical CDUS application. Method: Thirty-six female Spraque-Danles rats that have been pregnant for fourteen days were divided into fetal group (twenty-four female Spraque-Danles rats) and young animal group (twelve female Spraque-Danles rats) according to the sample-drawing time, the sample-drawing time of fetal group was 24h after irradiation and that of young animal group was lOd after birth, twenty-four female Spraque-Danles rats of fetal group were divided into four groups averagely and randomly according to irradiating time, control group (group I ) was sham-irradiation, group II-IV were irradiated by diagnostic CDUS (Sequeoia-512, 4V1, H3.0MHz, CD=3.0MHz, Tis=1.8, MIcd=1.6) for 10 minutes , 20 minutes and 30 minutes respectively. Twelve female Spraque-Danles rats of young animal group were divided into two groups averagely and randomly, control group (group V) were sham-irradiation, group VI was irradiated for 30 minutes, fetal rats' hearts and intestines of group I -IV were removed at 24hafter irradiation, young rats' hearts of group V-VI were removed 10d after birth. HE Stain was done for microscope observing, apoptosis cells were detected with TUNEL (in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling), and ultrastructure changes were observed by transmission electron microscope.Results: There was no abnormal changes in fetal rats' and young rats' myocardial cells among all groups under microscope, and there was no significant difference in apoptosis in fetal rats' and young rats' myocardial cells among I , II and III (P>0.05), but myocardial cell apoptosis increased in group IV (IVvs I , P<0.05). There was significant difference in myocardial cell apoptosis between fetal group and young group(P<0.05), but there was no significant difference in myocardial cell apoptosis between group V and groupVI. There was no abnormal changes in fetal rats' intestinal epithelial cells among group I -IV under microscope, and there was no significant difference in intestinal epithelial cell apoptosis between group I and II (P>0.05), but intestinal epithelial cell apoptosis increased remarkably in group III and IV(IIIvs I , P<0.05; IVvs I, P<0.01). Apoptotic changes of myocardial cells and intestinal epithelial cells were observed in group IV by transmission electron microscope, which showed margination and condensation of the nuclear chromatin, etc.Conclusion: Continuous irradiation beyond 30 minutes by diagnostic CDUS may result in fetal rat's myocardial cell apoptosis, but this phenomenon will disappear after birth. Continuous irradiation beyond 20 minutes by diagnostic CDUS may result in fetal rat's intestinal epithelial cell apoptosis. |
