OBJECTIVETo investigate the degree of injury to microtubule of myocardium at early post-hypoxia stage.

METHODSCardiomyocytes from Wistar rats were isolated and cultured, and they were then divided into normal control and hypoxia groups. The distribution and morphological changes in microtubules were observed with laser confocal microscopy and scanning electron microscope at 10, 20, 30 post-hypoxia minutes (PHM) and 1 post-hypoxia hour (PHH). Then the fluorescence intensity of alpha-microtubule was detected with RT-PCR, the morphology of microtubule was observed, and the expression of dissociative alpha-microtubule was determined by Western blot.

RESULTSCompared with normal control group, the bead-like structure of the microtubule in hypoxia group disappeared at 10 PHM, but no obvious change was observed in the distribution and number of microtubules. Despite the disappearance of bead-like structure of the microtubule, the microtubule derangement and loss of microtubule at the edge of cell were observed at 20 PHM. The fragmentation, derangement of texture, and loss of regularity in cardiomyocytes were observed at 30 PHM and 1 PHH. The fluorescence intensity of alpha-microtubule in hypoxia group was evidently decreased than that in normal group in a time-dependent manner. The expression of dissociative alpha-microtubule in hypoxia group at 10 PHM (46,644 +/- 145) was obviously higher than that in normal group (13,357 +/- 98, P < 0.01), and its increase was maintained with elapse of time.

CONCLUSIONMicrotubule injury to cardiomyocytes occurs at early stage of post-hypoxia, with destruction of its structure and distribution.