OBJECTIVETo observe the protective effects of paeonol, paeoniflorin, and their compatibility on in vitro cultured cardiomyocytes suffering from hypoxia-reoxygenation injury.

METHODSCardiomyocytes from neonatal rats were in vitro cultured and injured by a hypoxia of 2.5 - 5 h and a following 2-h reoxygenation. To observe the effects of paeonol and paeoniflorin, four doses of 100, 75, 50 and 25 mg/L were respectively set up. And to observe the compatibility of paeonol and paeoniflorin, five doses were set up as follows: paeonol 40 and 20 mg/L, paeoniflorin 40 and 20 mg/L, compatibility of paeonol 20 mg/L and paeoniflorin 20 mg/L. The above drugs were incubated with cardiomyocytes during the hypoxia and reoxygenation period respectively. No drug intervention was given to the model group, while no modeling was given to the normal control group. The transudatory creatine kinase (CK), lactate dehydrogenase (LDH), and malondialdehyde (MDA) in the culture medium were determined after the hypoxia period and the reoxygenation period respectively, and the total outleakage and the leakage inhibition ratio during the whole procedure were calculated. Results of each group were got from parallel operations for 5 times.

RESULTSCompared with the normal control group, the MDA leakage increased 2.5 h after hypoxia, the leakage and the total outleakage of CK, LDH, and MDA all significantly increased 3 and 5 h after hypoxia, and 2 h after reoxygenation. The leakage inhibition ratio of each index decreased with statistical difference (P<0.01, P<0.05). Compared with the model group, the leakage and the total outleakage of LDH and MDA both decreased in the high dose paeonol group, and the high and middle dose paeoniflorin groups after hypoxia and 2 h after reoxygenation (P<0.01, P<0.05), and the leakage inhibition ratio of each index increased (P<0.01, P<0.05). However, the leakage and the total outleakage of CK decreased in the low dose and the extreme low dose paeonol groups only 2 h after reoxygenation (P<0.01, P<0.05), while the leakage inhibition ratio of CK increased (P<0.01). The leakage and the total outleakage of LDH decreased in the extreme low dose paeoniflorin group only 2 h after reoxygenation (P<0.01), while the leakage inhibition ratio of LDH increased (P<0.01). The effects of their compatibility showed no significant difference (P>0.05).

CONCLUSIONSPaeonol, paeoniflorin, and their compatibility all have remarkable protective effects on in vitro cultured cardiomyocytes suffering from hypoxia-reoxygenation injury. There was no significant synergistic effect when paeonol was used with paeoniflorin together.