[Calcium-sensing receptor promotes endotoxin-induced myocardial injury through the JNK pathway].

To investigate the effects of calcium-sensing receptor (CaSR) on the c-Jun N-terminal kinase (JNK) in myocardial injury induced by endotoxin. The endotoxic model of neonatal rats was made by intraperitoneal injection of LPS(5 mg/kg). Neonatal Wistar rats were randomly divided into 6 groups: ①control group (saline group), ②endotoxin (LPS) group, ③LPS + CaSR agonist group, ④LPS + CaSR inhibitor group, ⑤LPS + JNK inhibitor group, ⑥LPS + CaSR inhibitor + JNK inhibitor group. The morphology of myocardium was observed by HE staining. The content of lactate dehydrogenase(LDH) in serum was determined. And the expression of IL-6 mRNA was detected by PCR. The protein expressions of CaSR and JNK were analyzed by Western blot. Compared with the control group, the myocardial injury was aggravated in the LPS group. The content of LDH and the expressions of IL-6 mRNA, CaSR and JNK were increased significantly (＜0.05). Compared with the LPS group,myocardial injury was aggravated in the CaSR agonist group. The content of LDH and the expressions of IL-6 mRNA,CaSR and JNK were increased (＜0.05). In the CaSR inhibitor group,myocardial injury was reduced. The content of LDH and the expressions of CaSR and JNK were decreased (＜0.05). In the JNK inhibitor group,myocardial injury was further alleviated. The content of LDH and the expressions of IL-6 mRNA, CaSR and JNK were decreased (＜0.05). Myocardial injury was significantly reduced in the CaSR inhibitor + JNK inhibitor group. The content of LDH and the expressions of IL-6 mRNA, CaSR and JNK were further reduced (＜0.05). CaSR is involved in myocardial injury induced by LPS in neonatal rats perhaps through the JNK pathway.