| Objective:To investigate the impact of chest hypo-fractionation irradiation onheart damage in mice so as to provide a reference for its clinical application.Method:Forty-eight male and female SPF C57BL/6 mice weighing 18-25 g were randomly divided into group A:control group.Group B:Conventional radiotherapy group:single dose of 2Gy;Group C: given a single dose of 12Gy;Group D: given a single dose of 18 Gy.12 mice in each group A,B,C,and D.The mice were monitored at 2 weeks,4 weeks,6 weeks,and8 weeks after the experiment:Weight,activity status,consciousness state,anatomy of mice,detection of cardiac injury by cardiac troponin I(cTnI),aspartate aminotransferase(AST),and myocardial tissue extraction by eyeball sampling,hematoxylin-eosin(HE)The morphological changes of myocardial tissue were observed by staining,and the expression of Bcl-2 and Bax in myocardial tissue was detected by immunohistochemistry.Results : Compared with the control group,C and D groups showed a trend of decreasing body weight after radiotherapy and increased after.and the body weight of group B gradually increased.At the same time,compared with the control group and B group,there was some degree of congestion and edema between myocardium and myocardium in two groups of mice,and there was a disorder between the cells in the arrangement,with a small amount of inflammatory cells infiltrating,and mild fibrosis.And other pathological changes.The pathological changes in group D were more obvious than those in group C and occurred earlier than in group C.There were statistically significant differences in troponin I(cTnI)and aspartate aminotransferase(AST)values between groups in each group of mice.With the increase of radiotherapy dose,the value of cTnI increased,and the difference was statistically significant(P<0.05).Between the same group,the values of cTnI and AST in the control group and B group did not reach statistical significance with time(P>0.05),while C group and D group prolonged with time,cTnI,AST The comparison of the values was statistically significant(P<0.05).However,after 4 weeks,the AST value showed a decreasing trend.After 6 weeks,the cTnI value showed a decreasing trend.There was no significant difference in cTnI and AST between the control group and the B group during the experimental observation period(P>0.05).In addition,Pearson correlation test found no correlation between radiotherapy dose and detection time(P>0.05).The expression of Bcl-2 in each experimental group was relatively low,and at the same detection time point,there was astatistically significant difference in the expression of Bcl-2 and Bax among the groups(P<0.01).In the comparison of different detection time points,Between the same group,there was no significant difference in Bcl-2 and Bax between the control group and the B group(P>0.05).Compared with the C group and the D group,the values of the Bcl-2 and Bax were statistically different.Differences(P<0.05).There was no significant difference in the Bcl-2 and Bax valuesbetween the control group and the 2Gy radiotherapy group during the observation period at the same time point(P > 0.05).Conclusion : High-dose,low-segment mode chest X-rayirradiation can cause myocardial radiation damage in mice,and the severity of myocardial injury increases with the increase of radiation dose and time.The mechanism may be related to the increased expression of the pro-apoptotic protein Bax and the inhibition of apoptosis induced by decreased expression of the apoptosis protein Bcl-2.In addition,conventional splitting of2 Gy irradiation has no significant effect on the early radiation damage of the mouse heart. |
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