Protective Effects Of Pohygonatum Sibiricmu Polyxaccharides Preconditioning On Anoxia/Reoxygenation Injury In Cultured Neonatal Rat Myocardial Cells

Objective : To investigate the protective effects and the mechanisms of Pohygonatum Sibiricmu Polyxaccharides (PSP) preconditioning on anoxia/ reoxygenation (A/R) injury in cultured neonatal rat myocardial cells.Methods: The myocardial cells were isolated from SD neonatal rats and cultured cells were randomly divided into four groups after cultured for 48 hours (the experiment was duplicated 6 times in each groups): control group, A/R group, Anoxia preconditioning group (APC+A/R group), PSP preconditioning group (PSP+A/R group). Various techniques were adopted to detect the cells and cellular products:①the levels of myocardial cells viability rate were assayed by MTT colorimetric method;②the levels of lactate dehydrogenase (LDH), superoxide dismutase (SOD), and malondialdehyde (MAD) were assayed by corresponding kits;③the ratio of myocardial cells apoptosis was detected by flow cytometry;④Intracellular Ca2+ concentration was detected by flow cytometry.Results: 1. Cell viability: the cell viability of A/R group (43.18±3.10%) was significantly lower than that of control group (94.22±1.56%), APC+A/R group (72.98±2.94%) and PSP+A/R group (69.82±3.17%) (p<0.01, respectively). There was no significant difference between the cell viability of APC+A/R group and that of PSP+A/R group (p>0.05). 2. LDH activity: the LDH activity of A/R group (53.51±2.92U/L) was significantly higher than that of control group (11.29±1.35U/L), APC+A/R group (21.35±1.38U/L) and PSP+A/R group (23.35±1.98U/L) (p<0.01, respectively). There was no significant difference between the LDH activity of APC+A/R group and that of PSP+A/R group (p>0.05). 3. SOD activity: the SOD activity of A/R group (6.34±0.95U/L) was significantly lower than that of control group (13.84±1.36U/L), APC+A/R group (11.59±1.67U/L) and PSP+A/R group (12.25±1.88U/L) (p<0.01, respectively). There was no significant difference between the SOD activity of APC+A/R group and that of PSP+A/R group (p>0.05). 4. MDA content: the MDA content of A/R group (1.68±0.16μmol/L) was significantly higher than that of control group (0.42±0.09μmol/L), APC+A/R group (0.81±0.09μmol/L) and PSP+A/R group (0.79±0.08μmol/L) (p<0.01, respectively). There was no significant difference between the MDA content of APC+A/R group and that of PSP+A/R group (p>0.05). 5. Cell apoptosis rate: the cell apoptosis rate of A/R group (34.27±1.94%) was significantly higher than that of control group (6.62±0.68%), APC+A/R group (14.35±1.12%) and PSP+A/R group (17.68±1.87%) (p<0.01, respectively). There was no significant difference between the cell apoptosis rate of APC+A/R group and that of PSP+A/R group (p>0.05). 6. The average fluorescence intensity of intracellular calcium (reflecting the concentration of intracellular Ca2+): the average fluorescence intensity of intracellular calcium of A/R group (164.66±20.42) was significantly higher than that of control group (4.86±0.76), APC+A/R group (24.17±3.82) and PSP+A/R group (21.25±2.29) (p<0.01, respectively). There was no significant difference between the average fluorescence intensity of intracellular calcium of APC+A/R group and that of PSP+A/R group (p>0.05).Conclusion: PSP could protect myocardial cells against A/R injury. The protective effect of PSP preconditioning was related to the diminution of oxygen free radical and the inhibition of intracellular calcium overload.