ABSTRACT
OBJECTIVE：To st udy the effects of α7 nicotinic acetylcholine receptor agonists （PNU282987）on improving cardiac remodeling of mice and Janus kinase 2/signal transducer and activator of transcription 3（JAK2/STAT3）signaling pathway. METHODS：Male Kunming mice were randomly divided into normal control group ，model group ，propranolol group （positive control，i.g. 40 mg/kg）and PNU 282987 low-dose，medium-close and high-dose groups （intraperitoneal injection of 0.5，1.0，3.0 mg/kg），with 10 mice in each group. Except for the normal control group ，mice in the other groups were given isoproterenol （ISO，30 mg/kg） subcutaneously for 7 days to induce the cardiac remodeling model. After 30 minutes of ISO injection ， administration groups were given relevant liquid ，once a day ，for 7 consecutive days. Twelve hours after last administration ，the left ventricular ejection fraction （EF）and left ventricular short axis shortening rate （FS）of mice in each group were measured ，and the whole heart mass index （HMI）was calculated ；the pathological changes of myocardium were observed. The serum contents of lactate dehydrogenase （LDH），creatine kinase （CK），tumor necrosis factor α（TNF-α），interleukin 6（IL-6），the protein expression of intercellular adhesion molecule 1（ICAM-1）and adhesion molecule 1（VCAM-1）were also determined. The ratios of p-JAK2/JAK2，p-STAT3/STAT3 in myocardial tissue were detected. RESULTS ：Compared with normal control group ，EF and FS of model group were significantly reduced ，HMI，the contents of LDH，CK，TNF-α and IL-6，the protein expression of ICAM- 1 and VCAM- 1，the ratio of p-JAK 2/JAK2 and p-STAT 3/STAT3 were increased significantly （P＜0.05 or P＜0.01）； blue collagen deposition in the interstitium of myocardium was obvious，and the degree of fibrosis was severe. Compared with model group ， the EF and FS of the mice in the medium-dose and high-dose groups were increased significantly ， HMI （except for PNU 282987 medium-dose group ），the contents of LDH （except for PNU 282987 medium-dose group ），CK，TNF-α and IL-6，the protein expression of ICAM- 1 and VCAM- 1，the ratio of p-JAK 2/JAK2 and p-STAT 3/STAT3 were decreased significantly （P＜0.05 or P＜ 0.01）；blue collagen deposition in the myocardial interstitium was significantly reduced ，and the degree of myocardial fibrosis was significantly reduced. There was no significant difference in the comparison of the above indicators in PNU 282987 low-dose group （P＞0.05）. CONCLUSIONS ：PNU282987 can improve cardiac remodeling of mice ，the mechanism of which may be associated with inhibiting JAK 2/STAT3 signaling pathway.