Jian-xun LIU
Research Center, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Xiyuan Caochang, Haidian District, Beijing 100091, China

Abstract:

Aim: Salvianolic acid B (Sal B) exhibits cardioprotection against ischemic injury, but the effects of Sal B on autophagy regulation in cardiac myocytes remain unknown. The main objectives of this study were to investigate the protective or lethal role of autophagy and study the effects of Sal B on autophagy in starving myocytes.

Methods: Cardiac myocytes were incubated under starvation conditions (GD) for 0, 1, 2, 3, and 6 h. Autophagic flux in starving cells was measured via Chloroquine (3 µmol/L). After myocytes were treated with Sal B (50 µmol/L) in the presence or absence of Chloroquine (3 µmol/L) under GD 3 h, the amount of LC3-II, the abundance of LC3-positive fluorescent dots in cells, cell viability and cellular ATP levels were determined by immunoblotting, immunofluorescence microscopy, MTT assay and luminometer, respectively. Moreover, electron microscopy (EM) and immunofluorescent duel labeling of LC3 and Caspase-8 were used to examine the characteristics of autophagy and apoptosis.

Results: Immunoblot analysis showed that the amount of LC3-II in starving cells increased in a time-dependent manner accompanied by increased LC3-positive fluorescence and decreased cell viability and ATP content. Sal B inhibited the increase in LC3-II, reduced the abundance of LC3 immunofluorescence and intensity of Caspase-8 fluorescence, and enhanced cellular viability and ATP levels in myocytes under GD 3 h, regardless of whether Chloroquine was present.