Ishiyama S, Hiroe M, Nishikawa T, Shimojo T, Abe S, Fujisaki H, Ito H, Yamakawa K, Kobayashi N, Kasajima T, Marumo F
Second Department of Internal Medicine, Tokyo Medical and Dental University, Japan.
J Immunol. 1998 Nov 1;161(9):4695-701.
The mechanisms responsible for myocardial injury and cell death in myocarditis are still unclear. We examined whether myocardial cell death occurs via apoptosis in myosin-induced autoimmune myocarditis in rats and whether the Fas/Fas ligand (FasL) system plays a role in this apoptosis. On days 14, 17, 21, and 35 after immunization with porcine heart myosin, some cardiomyocytes and infiltrating lymphocytes were found to be apoptotic on in situ terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end-labeling (TUNEL) assay, but none was on day 60 and in control rats. Apoptotic indices peaked at day 17, and laddering of genomic DNA from the affected myocardium was observed on days 17 and 21 on agarose gel electrophoresis. The expression of Fas mRNA and protein was detected on days 17 and 21 in some cardiomyocytes and infiltrating lymphocytes by Northern blot analysis and immunohistochemistry, respectively. In addition, FasL was detected in some infiltrating lymphocytes on days 14, 17, and 21 by both in situ hybridization and immunostaining, and FasL-positive lymphocytes were mainly CD4+ cells. Some rats were injected with anti-Fas Ab (0.1 mg/kg) or anti-FasL Ab (0.1 mg/kg), and subsequently, inflammatory lesions exhibited less severe than did untreated rats with myocarditis. These findings suggest that cell death via apoptosis of cardiomyocytes and lymphocytes is one of the mechanisms of myocardial injury in autoimmune myocarditis, and that the Fas/FasL system might play a role in the induction of this apoptosis.
心肌炎中心肌损伤和细胞死亡的机制仍不清楚。我们研究了在大鼠肌球蛋白诱导的自身免疫性心肌炎中，心肌细胞死亡是否通过凋亡发生，以及Fas/Fas配体（FasL）系统是否在这种凋亡中起作用。在用猪心脏肌球蛋白免疫后的第14、17、21和35天，原位末端脱氧核苷酸转移酶介导的dUTP-生物素缺口末端标记（TUNEL）检测发现一些心肌细胞和浸润淋巴细胞发生凋亡，但在第60天以及对照大鼠中未发现凋亡现象。凋亡指数在第17天达到峰值，在第17和21天通过琼脂糖凝胶电泳观察到受影响心肌的基因组DNA出现梯状条带。分别通过Northern印迹分析和免疫组织化学在第17和21天在一些心肌细胞和浸润淋巴细胞中检测到Fas mRNA和蛋白的表达。此外，通过原位杂交和免疫染色在第14、17和21天在一些浸润淋巴细胞中检测到FasL，FasL阳性淋巴细胞主要是CD4+细胞。给一些大鼠注射抗Fas抗体（0.1 mg/kg）或抗FasL抗体（0.1 mg/kg），随后，炎症病变比未治疗的心肌炎大鼠表现得较轻。这些发现表明，心肌细胞和淋巴细胞通过凋亡导致的细胞死亡是自身免疫性心肌炎中心肌损伤的机制之一，并且Fas/FasL系统可能在这种凋亡的诱导中起作用。
