[The optimal concentration for the protective effect of emulsified isoflurane on the neonatal rat cardiac myocytes hypoxia/reoxygenation injury of primary culture].

Objective: To optimize the concentration of emulsified isoflurane (EI) for the protective effect on primary cultured neonatal rat hypoxia/reoxygenation (H/R) cardiac myocytes.

Methods: To prepare the H/R injury model on the basis of in-vitro neonatal rat cardiac myocytes culture and divide them into 13 groups at random, namely, normal control group (N group), H/R group, H/R+fat emulsion group (F group), the one, two, three, four, five, six, seven, eight, nine and ten times of 0.28 mmol/L EI designated as EI1-EI10 group. The supernatants of cell culture from each group were detected for lactate dehydrogenase (LDH) activity and the level of cardiac troponin-I (cTnI). The cellular homogenates of each group were prepared for the detection of superoxide dismutase (SOD) and malondialdehyde (MDA). Inverted microscope was applied to observe the characteristics of cardiac myocytes growth and changes of its forms.

Results: Compared to N group, the LDH, MDA and cTnI of others all increased (P < 0.05) and SOD decreased (P < 0.05). Compared to H/R group, LDH, MDA and cTnI of each EI dose group decreased significantly (P < 0.05), but SOD increased (P < 0.05). Compared to EI6 group, the LDH, MDA and cTnI in the other groups of EI increased (P < 0.05) and the SOD decreased (P < 0.05). As the EI concentration (increasing by multiple) increased, the LDH, MDA and cTnI in the EI1 to EI6 group decreased gradually and SOD gradually increased (P < 0.05), the LDH, MDA and cTnI in the EI7 to EI10 group increased gradually and SOD gradually decreased (P < 0.05).

Conclusion: EI has the protective effect on the neonatal rat cardiac myocytes with H/R injury, the optimal concentration for the protective effect on cardiac myocytes is 1.68 mmol/L, and its mechanism may be associated with its anti-oxidation effect.