[Granulocyte colony stimulating factor attenuated myocardial apoptosis via Janus kinase 2/signal transducer and activator of transcription signal transduction pathway in rats with coronary microembolization].
OBJECTIVE
To investigate the effects of granulocyte colony stimulating factor (G-CSF) on myocardial apoptosis following coronary microembolization (CME) and possible role of Janus kinase/singnal transducer and activator of transcription (JAK/STAT) pathway in this process.


METHODS
A total of 92 male Sprague Dawley rats were randomized into CME (n = 24), G-CSF (100 microg x kg(-1) x d(-1) i.p. 2 hours post CME for 5 days, n = 24), JAK2 inhibitor AG490 (G-CSF plus AG490, 5 mg x kg(-1) x d(-1) i.p. 2 hours post CME for 5 days, n = 24), all rats received left ventricular injection of homologous microthrombotic particle suspension post clamping the ascending aorta. Sham-operated group (n = 20) served as control. The rats were sacrificed at day 3, 7, 14 and 28 after operation. The myocardial mRNA expressions of Bcl-2, Bax, Fas, FasL and GAPDH which was used as the intercomparison, were evaluated by real time PCR. The ratio of Bcl-2/Bax was compared. The protein expression of Caspase-3, cleaved PARP, t-JAK2, p-JAK2, t-STAT3 and p-STAT3 were detected by western blot. Myocardial apoptosis were examined by TUNEL staining.


RESULTS
Compared with Sham rats, the mRNA of Bcl-2, Bax, Fas and FasL significantly increased whereas the ratio of Bcl-2/Bax (0.28 +/- 0.04 vs. 2.98 +/- 0.49) significantly decreased and the protein expression of Caspase-3 (0.762 +/- 0.129 vs. 0.133 +/- 0.027), PARP (0.992 +/- 0.146 vs. 0.386 +/- 0.074) and the myocardial apoptosis index (17.2 +/- 1.9 vs. 1.2 +/- 0.6) significantly increased in CME hearts (all P < 0.05). rhG-CSF significantly attenuated CME induced changes and cotreatment with JAK2 inhibitor AG490 abolished the effects of rhG-CSF. The protein expressions of t-JAK2 and t-STAT3 among the groups were similar. P-JAK2 and p-STAT3 protein expressions were significantly increased in G-CSF group compared to other groups (P < 0.05).


CONCLUSIONS
G-CSF attenuated myocardial apoptosis induced by CME via JAK2/STAT3 pathway.
Zhang
Fei-Long
FL
Department of Cardiology, Affiliated Union Hospital of Fujian Medical University, Fuzhou 350001, China.
Chen
Liang-Long
LL
Li
Shu-Mei
SM
Wang
Wei-Wei
WW
D000818:Animals; D017209:Apoptosis; D003324:Coronary Artery Disease / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D017700:Embolism, Cholesterol / Q000378:metabolism* / Q000473:pathology; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D053614:Janus Kinase 2 / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D050791:STAT Transcription Factors / Q000378:metabolism*; D015398:Signal Transduction
D050791:STAT Transcription Factors; D016179:Granulocyte Colony-Stimulating Factor; C507927:Jak2 protein, rat; D053614:Janus Kinase 2