[Anti-apoptotic effects of mesenchymal stem cells on cardiac myocytes: in vitro study with rats].
OBJECTIVE
To investigate the anti-apoptotic effects of mesenchymal stem cells (MSCs) on hypoxia-injured cardiac myocytes.


METHODS
MSCs were isolated from the bone marrow of 6 - 8 week-old Sprague-Dawley rats. Cardiac myocytes from neonatal rat were cultured under hypoxia, then the hypoxia-injured cardiac myocytes were divided into 3 groups: cultured alone (control group), co-cultured with the MSCs, or co-cultured in MSC-conditioned media in conditions of anoxia (95% N(2) + 5% CO(2), continuous hypoxia group) or normoxia [hypoxia/reoxygen (H/R) group] for 72 hours. The cell apoptosis was measured by Hoechst staining, and Western blotting was used to test the protein expression of Bcl-2 and Bax in the cardiac myocytes.


RESULTS
The apoptotic rate of the cardiac myocytes cultured under hypoxia was 51.6% +/- 2.4%, significantly higher than those of the cardiac myocytes co-cultured with MSCs and MSC-conditioned media respectively (15.1% +/- 5.4% and 24.0% +/- 4.2% respectively, both P < 0.001). The apoptotic rate of the H/R group was 20.9% +/- 2.7%, significant higher than that of the MSC group (11.5% +/- 3.7%, P < 0.05), however, not significantly different from that of the MSC-conditioned media group (20.1% +/- 4.2%, P > 0.05). The protein expression of Bcl-2 was not significantly different among different groups. The Bax protein expression of the MSC group and MSC-conditioned media group were 2.28 +/- 0.46 and 3.01 +/- 0.26 respectively, both significantly lower than that of the control group (7.62 +/- 1.28, both P < 0.05). The decreased expression of Bax in the cardiac myocytes was greatly related to the decreasing of apoptosis.


CONCLUSIONS
Co-cultured MSCs show significant anti-apoptotic effects on cardiac myocytes both in continuous hypoxia and in H/R conditions with the possible mechanism of direct cell to cell interaction and paracrine of cytokines which effect the expression of Bax in the myocytes.
Qu
Huan
H
Department of Cardiology, Peking University Third Hospital, Institute of Cardiovascular Research, Peking University Health Sciences Center, Beijing 100083, China.
Guo
Yan-hong
YH
Zhu
Xiao-jun
XJ
Gao
Wei
W
Mao
Jie-ming
JM
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis; D015153:Blotting, Western; D001854:Bone Marrow Cells / Q000166:cytology; D015687:Cell Hypoxia; D002478:Cells, Cultured; D018920:Coculture Techniques; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis
C494828:Bax protein, rat; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein