Preservation of the pHi during ischemia via PKC by intermittent hypoxia

In intermittent hypoxia adaptation (IHA) rat cardiomyocytes, the relationship between activated protein kinase C and intracellular acidification regulation during ischemia-reperfusion (I/R) was tested. Using [H+] indicator BCECF-AM, we analyzed the alterations of intracellular pH (pHi) in normoxia and IHA rat cardiomyocytes during I/R. With the time of ischemia, the pHi decreased progressively in normal cardiomyocytes, but fewer alterations in IHA myocytes. Treatment of IHA and normoxia cardiomyocytes with 5 μM chelerythrine delayed the pHi recovery during post-ischemia. In contrast, the application of 1 μM phorbol 12-myristate 13-acetate in normoxia cardiomyocytes preserved the pHi during I/R, which was similar to that in IHA cardiomyocytes. Our data suggest that the stable PKC activation might contribute to preservation of the pHi, which may be beneficial to maintain cardiac function during I/R in IHA rats.