Objective To study the effect of p38 signaling pathway in cardiac muscle cells of acute myocardial infarction（ AMI） rats with heart blood stasis syndrome on differentiation of bone marrow mesenchymal stem cells（ BMSCs）.Methods Totally 48 SD rats were randomized into the healthy control group

sham operation group（ AMI models）

model group（ AMI models with heart blood stasis syndrome）

No.1 injection group（ AMI models with heart blood stasis syndrome injected of 100μl BMSCs cell suspension）

No.2 injection group（ AMI models injected of 100μl BMSCs cell suspension） and No.3 injection group（ healthy rats injected of 100μl BMSCs cell suspension）

with 8 in each.The expressions of phosphorylated p38（ p-p38） signal transduction proteins

cardiac Desmin

myosin heavy chain（ MHC） and cardiac transcription factor GATA-4 mRNA were detected.Results The expressions of p-p38 proteins in the model group and No.1 injection group were significantly higher than those in the sham operation group and healthy control group（ P < 0.05）.The expressions of p-p38 proteins in No.1 injection group were significantly higher than those in the model group

No.2 injection group and No.3 injection group（ P < 0.05）.The Desmin-Brdu and MHC-Brdu double-transfected cells were expressed in No.1 injection group but not expressed in No.2 injection group and No.3 injection group.There was no GATA-4 mRNA expression in No.3 injection group.The expression of GATA-4 mRNA in No.1 injection group was significantly higher than that in No.2 injection group（ P < 0.05）.The expression of p-p38 was positively correlated with the expression of GATA-4 mRNA（ P <0.05）

but with no significant correlation with Desmin-Brdu and MHC-Brdu.Conclusion BMSCs transplantation can induce myocardial cells of AMI rats with heart blood stasis syndrome.It is associated with the activation of p38 signal transduction pathway.