病毒性心肌炎小鼠调节性B细胞的变化

Changes of regulatory B cells in mice with viral myocarditis induced by Coxsackie virus

目的观察病毒性心肌炎小鼠不同时间点调节性B淋巴细胞(Breg)亚群的变化,探讨其在病毒性心肌炎发病中的作用。方法将小鼠随机分为实验组和对照组,实验组腹腔注射柯萨奇病毒B3(CVB3),对照组注射等量磷酸盐缓冲液(PBS)。依据注射后的时间,实验组和对照组均设1周和2周时间点亚组。应用苏木素伊红染色后观察心肌病理改变并计算心肌病理积分,采用RT-PCR法检测心肌组织中CVB3 mRNA的表达水平,采用流式细胞术检测小鼠脾脏Breg细胞亚群占CD19+细胞的比例。结果实验组心肌炎症水平及CVB3 mRNA表达水平均明显高于对照组;实验组1周亚组心肌组织病理积分低于2周亚组,但实验组1周亚组心肌CVB3 mRNA表达水平却高于2周亚组,差异均有统计学意义(P<0.05)。实验组小鼠脾Breg细胞比例均高于对照组,且实验组1周亚组小鼠脾Breg细胞比例高于2周亚组,差异有统计学意义(P<0.05)。结论病毒性心肌炎小鼠中调节性B细胞表达增高,其可能参与病毒性心肌炎的发病过程。

Objective To observe the changes of regulatory B （Breg） cells in mice with viral myocarditis （VMC） in- duced by coxsackie virus B3 （ CVB3 ）, and to explore the role of Breg ceils in VMC mice. Methods Balb/c male mice were randomly divided into expefinaental group and control group. Mice in the experimental group were intraper- itoneally infected with CVB3 to establish VMC models, while mice in the control group were treated with phosphate- buffered saline （PBS） intraperitoneally. According to the time after injection of CVB3 or PBS, all mice in the two groups were randomly divided into 1-week and 2-week subgroups. Myocardial histopathological scores were determined in hematoxylin eosin stained sections. Expression of CVB3 mRNA in heart was measured with real-time reverse tran- scription-polymerase chain reaction （RT-PCR）, and the frequency of splenic Breg subsets in CD19 ＋ B cells was meas- ured with flow cytometry. Results There were significant differences in the pathological scores and expression of myo- cardial CVB3 mRNA between the VMC mice and controls. The pathological scores of l-week experimental subgroup were lower than those of 2-week experimental subgroup, while the expression of myocardial CVB3 mRNA in 1-week experimental subgroup was higher than that in 2-week experimental subgroup （ all P 〈 0.05 ）. Compared with controls, the frequency of splenic Breg cells in the VMC mice increased significantly at different time points. Moreover, the fre- quency of splenic Breg cells in 1-week experimental subgroup was higher than that in the 2-week experimental subgroup （ all P 〈 0.05 ）. Conclusion Breg cells increase in mice with CVB3-induced VMC, indicating that Breg cells mayplay an important role in the pathogenesis of CVB3-induced VMC.