CD161^+调节性T细胞降低风湿性心脏病大鼠瓣膜损伤的作用及机制

Role and mechanism of CD161^+ regulatory T cells in alleviating cardiac valve injury in rheumatic heart disease rats

目的探讨CD161^+调节性T细胞(Treg)降低风湿性心脏病大鼠瓣膜损伤的作用及机制。方法流式细胞术分选CD161^-和CD161^+ Treg并进行培养, ELISA检测Treg培养上清液白细胞介素10(IL-10)和转化生长因子β(TGF-β)的含量;A组溶血性链球菌悬液与Freund完全佐剂混合后建立风湿性心脏病大鼠模型,分为对照组、 CD161^- Treg组、 CD161^+ Treg组。处理1周后,收集大鼠的心脏血和二尖瓣瓣膜。流式细胞术检测心脏血单个核细胞滤泡辅助性T(Tfh)细胞、 B细胞和浆细胞比例, HE染色检测瓣膜组织病理变化,免疫组织化学染色法检测瓣膜组织中B细胞和浆细胞数目, ELISA检测血清IL-21水平。结果 CD161^+ Treg分泌IL-10和TGF-β的能力显著高于CD161^-Treg。与注射CD161^- Treg的大鼠相比,注射CD161^+Treg能够显著降低瓣膜组织损伤,减少瓣膜组织B细胞和浆细胞的比例;且CD161^+Treg注射能够减少大鼠血液中Tfh细胞、 B细胞和浆细胞的比例,血清中IL-21含量降低。结论 CD161^+Treg通过抑制Tfh细胞和B细胞增殖分化,降低风湿性心脏病的瓣膜损伤。

Objective To investigate the role of CD161^+ regulatory T cells(Treg) in reducing valve injury in rheumatic heart disease rats and the underlying mechanism. Methods CD161^- and CD161^+ regulatory T cells(Tregs) were separated by flow cytometry and then cultured. The concentrations of interleukin 10(IL-10) and transforming growth factor β(TGF-β) in the supernates were detected by ELISA. Rat models of rheumatic heart disease were established by mixing A type hemolytic streptococcus suspension with Freund’s complete adjuvant. They were divided into control group, CD161^-Treg group and CD161^+Treg group. One week later, heart blood and mitral valve were taken from the model rats. The proportion of follicular helper T(Tfh) cells, B cells and plasma cells was detected by flow cytometry. Histopathological changes were detected by HE staining and the number of B cells and plasma cells by immunohistochemical staining. ELISA was used to detect the level of IL-21 in serum. Results The ability of CD161^+Tregs to secrete IL-10 and TGF-β was significantly higher than that of CD161^-Tregs. Compared with the rats injected with CD161^-Tregs, CD161^+Tregs could significantly reduce the damage of valve tissue and the proportion of B cells and plasma cells in valve tissue. Moreover, CD161^+Tregs injection could reduce the proportion of Tfh cells, B cells and plasma cells in rat blood and decrease the content of IL-21 in serum. Conclusion CD161^+Tregs can reduce the valve injury of rheumatic heart disease by inhibiting the proliferation and differentiation of Tfh cells and B cells.