Abstract: Objective To study the protective mechanism of Gross Saponin Tribulus Terrestris (GSTT) on the neonatal rat ventricular cardiocytes injured by hypoxia and the effect on protein kinase C（PKC）. Methods The hypoxia-ischemia model was performed by treating the cultured neonatal rat ventricular cardiocytes with NaCN. The effect of GSTT(100 and 30 mg·L^-1) on the contents of εPKC and δPKC were detected by flow cytometry and laser confocal microscopy system. Results GSTT up-regulated εPKC and δPKC expressions. The contents of εPKC and δPKC in GSTT 100 mg·L^-1 group（1 325.00±53.25，810.55±36.89；66.22±6.23，40.12±2.21） were increased significantly than those in model group（792.00±32.36，492.40±30.15；32.70±2.78，29.28±4.82）（P<0.001，P<0.01；P<0.001，P<0.01）, and were higher than those in GSTT 30 mg·L^-1 group(998.00±23.21, 710.00± 38.12 ; 55.35±5.15, 35.68±3.89) （P<0.01，P<0.05；P<0.01，P<0.05）. Conclusion GSTT can protect cardiocytes through activating PKC signaling pathway.

Key words: protein kinase C, laser confocal microscopy, flow cytometry