Abstract: Ｏｂｊｅｃｔｉｖｅ：To explore the pathogenesis of cardiorenal syndrome（CRS） based on the effect of exosome miR155 on apoptosis of cardiorenal cells in rats with CRS by regulating p38MAPK signaling pathway.
Ｍｅｔｈｏｄｏｌｏｇｙ：SpragueDawley rats were randomly divided into control group, model group for 3 weeks, model group for 4 weeks, model group for 5 weeks, and model group for 6 weeks.Each group received 10 rats with intraperitoneal injection of normal saline or doxorubicin.Histomorphological changes were observed by HE staining.Cardiac function was detected by echocardiography.Serum NTpro BNP and KIM1 were detected by ELISA.Urea nitrogen and serum creatinine were detected by automatic biochemical analyzer.EXO Quick kit was used to extract plasma exosomes and detect them quantitatively.RTPCR, Westernblot  were used to detect expressions of p38MAPK mRNA, miR155, p38MAPK and pp38MAPK in heart and kidney tissue.The apoptosis of heart and kidney was detected by TUNEL.
Ｒｅｓｕｌｔｓ：Cardiac and renal function of rats in each group decreased after model establishment.Compared with the blank group,PP38 in the heart increased in the 4week group and the 5week group (P<005),6week group (P<001).Compared with the blank group,the kidney PP38 increased in the 4week group,the 5week group and the 6week group (P<001).Compared with the blank group,the apoptotic rate of heart and kidney cells increased in the 3week group,the 4week group,the 5week group and the 6week group (P<001); the plasma exosome content decreased in the 4week group,the 5week group and the 6week group (P<001); the exosome miR155 decreased in the 3week group,the 4week group,the 5week group and the 6week group (P<001),and the miR155 decreased in the heart and kidney tissue (P<001).
Ｃｏｎｃｌｕｓｉｏｎ：
The phosphorylation of p38 MAPK plays a key role in the apoptosis of cardiac and renal cells in CRS rats,and the exosome miR155 may play a regulatory role.