Role of protein kinase C in induction of vascular endothelial growth factor secretion by isoflurane in primary cultured rat cardiomyocytes / 中华麻醉学杂志

ABSTRACT

Objective To investigate the role of protein kinase C (PKC) in induction of vascular endothelial growth factor (VEGF) secretion by isoflurane in primary cultured rat cardiomyocytes. Methods Primary cultured neonatal rat cardiomyocytes were randomly divided into 6 groups ( n = 6 each) control group (group C), 3 different concentration isoflurane groups (group Ⅰ1-3 ), PKC inhibitor calphostin C group (group P), and PKC inhibitor + isoflurane group (group PI). The cells were exposed to 0.7%, 1.4% and 2.1% isoflurane for6 h in group Ⅰ1-3 respectivly. Calphostin C was added to the culture medium with a final concentration of 50 nmol/L in group P. Calphostin C was added to the culture medium with a final concentration of 50 nmol/L, then the cells were exposed to 1.4% isoflurane for 6 h in group PI. VEGF concentrations and expression of PKC isoforms were determined by ELISA and Western blot respectively. Results Compared with group C, the VEGF concentration was significantly increased in group Ⅰ2 and Ⅰ3, and PKCε expression was down-regulated in the cytoplasm while upregulated in the cytomembrane in group Ⅰ2 ( P ＜ 0.01 ), but no significant change was found in the parameters mentioned above in group Ⅰ2 ( P ＞ 0.05). PKCα, PKCδ and PKCζ expression was significantly higher in the cytoplasm than in the cytomembrane in group C and Ⅰ2. VEGF concentrations were gradually increased with the increase in isoflurane concentrations ( P ＜ 0.05). VEGF concentrations were significantly lower in group PI than in Ⅰ2 ( P ＜0.05) .Conclusion Isoflurane induces VEGF secretion in primary cultured rat cardiomyocytes through translocation of PKCε from the cytoplasm to the cytomembrane, suggesting that it is a mechanism of the cardioprotective effects of isoflurane.