Effects of microtubule disassembly on hypoxic injury of cultured cardiomyocytes / 第三军医大学学报

ABSTRACT

Objective To investigate whether microtubule disassembly plays an important role in the pathogenesis of the opening of mitochondria permeability transition pore (MPTP) in hypoxic cardiomyocytes and the decrease of its activity, resulting in its hypoxic injury. Methods Neonatal rat cardiomyocytes in primary culture were randomized as normoxia group (A), hypoxic group (B), normoxia treated with microtubule destabilizing agent (Colchicine) group (C), hypoxia treated with microtubule stabilizing agent (Taxol) group (D). At 0.5, 1, 3, 6, 12 h after treatment, polymeric tubulin was detected by immunofluorescence and Western blotting, mitochondria permeability transition pore (MPTP) open by coloading with calcein AM and cobalt chloride, and the activity of cells by measuring the mitochondrial-dependent reduction of MTT to formazan. Results Early microtubule disassembly, MPTP open and activity decrease of cardiomyocytes in both groups B and C were observed at 0.5 h after treatment. These phenomena all became more and more significant with the prolongation of treatment. However, microtubule disassembly, MPTP open and activity decrease of cardiomyocytes of group D were significantly lower than those of group B. Conclusion Microtubule disassembly happened at 0.5 h after hypoxic treatment. Microtubule stabling agent Taxol and destabilizing agent Colchicine can regulate microtubule integrity efficiently. The microtubule damage plays an important role in the hypoxic injury of cardiomyocytes.