The expression of main potassium channels of rat mesenchymal stem cells in microenvironment of myocardial ischemia in vivo

Objective: To observe the expression profile of main potassium channels in rat mesenchymal stem cells (MSCs) in microenvironment of myocardial ischemia in vivo. Methods: The myocardial infarction (MI) models of rats were established by ligating the left anterior descending coronary artery. Suspension MSCs labeled by green fluorescent protein(GFP) were injected into the surrounding area of the epicardium myocardial infarction (n=60). The protein expression of the main potassium channels Kv1.4, Kir2.1, Kv4.3 and Kca1.1 on the transplanted MSCs in the myocardial tissues of MI group were observed by immunofluorescence staining 3 days (MI-3d), 5 days (MI-5d), 7 days (MI-7d), and 9 days (MI-9d) after transplantation. The corresponding mRNA of the proteins mentioned above was acquired by laser capture microdissection and observed by Real-time PCR. Results: Immunofluorescence staining and Real-time PCR indicated that Kv1.4, Kir2.1 and Kv4.3 were detected from MSCs 3 days after the transplantation, but Kca1.1 was not found in any of the groups. Real-time PCR confirmed that the expressions of Kv1.4 and Kir2.1 in the three groups were significantly increased gradually with the time prolongation (3 d, 5 d, 7 d, P<0.05) while Kv4.3 in all of the groups had no significant difference, but expressed higher than no-transplantation MSCs. The transplanted MSCs decreased and disappeared gradually 9 days after transplantation. Conclusion: Transplanted MSCs can express some main potassium channels in the microenvironment of myocardial infarction model, but these differentiated cardiomyocytes are immature and cannot survive effectively for a long time in the special microenvironment.