ABSTRACT
Objective To investigate the roles of the activated p38 kinase in cell injury by observation of the effects of hypoxia and burn serum on cardiomyocyte p38 kinase and JNK activation. Methods Phosphorylation of p38 kinase and JNK in primary cultured neonatal rat cardiomyocytes before and after hypoxia and burn serum was determined by Western blotting. Effects of pretreatment with SB203580 at the dose of 10 ?mol/L on the changes of phosphorylation of p38 kinase in cardiomyocytes, lactate dehydrogenase (LDH) activity, cell vitality and apoptosis were investigated, respectively. Results Exposure of rat neonatal cardiomyocytes to hypoxia and burn serum resulted in a rapid and long lasting activation of p38 kinase but no significant activation of JNK. SB203580(10 ?mol/l), a selective inhibitor of p38 kinase, could inhibit p38 kinase activation dramatically, decrease the LDH activity in culture media and cell apoptosis significantly and improve cell vitality. Conclusion In the two stress activated signal pathways of MAPKs family, p38 kinase pathway, but not JNK, is the major pathway activated by hypoxia and burn serum and participates in the cardiomyocyte injury.
ABSTRACT
Objective To explore the effect of c fos antisense gene transfection on the protection of cardiomyocytes following hypoxia and burn serum treatment. Methods Burn serum was collected from Wistar rats with 30% total body surface area(TBSA) of Ⅲ degree burns. The mixture gas containing 1% O 2 was used as hypoxia model. The c fos antisense gene recombinant was constructed by genetic recombination technique. Cardiomyocytes from neonatal Wistar rats were cultured in vitro with hypoxia and burn serum treatment. c fos antisense gene recombinant was transfected into the cultured cardiomyocytes. Expression of c fos mRNA was determined by RT PCR. Expressions of c fos protein, troponin T and ? Tubulin in cardiomyocytes were determined by Western blotting in the transfected and non transfected groups. Results RT PCR results showed that the expression of c fos mRNA increased significantly in the non transfected group. But after transfection of c fos antisense gene recombinant, the expression of c fos mRNA decreased significantly as compared with the non transfected cardiomyocytes. Western blotting results showed that the expression of c fos protein in the transfected group decreased remarkably as compared with the non transfected group, but the expressions of ? Tubulin and troponin T increased significantly in the transfected group. Conclusion Burn serum and hypoxia can cause the injury of cardiomyocytes. c fos antisense gene recombinant transfection has the protective effect on cardiomyocytes exposed to burn serum and hypoxia.