Abstract: AIM: To observe the effects of microtubule stabilizer (Taxol) on the expression and distribution of Cx43 in cultured cardiac myocytes under hypoxia and investigate its new value as an anti-arrhythmic agent.METHODS: Cultured cardiac myocytes from newborn rats were exposed to hypoxia for 120 min with or without Taxol (a kind of microtubule stabilizer) in different concentrations. The expression of Cx43, polymerized tubulin and total tubulin were determined by western blots. Cx43 expression and distribution were detected by immunofluorescence staining and observed under laser scanning confocal microscope.RESULTS: In normal myocytes, Cx43 converge at nuclear membrane and intercalated discs in clusters. After 120 min hypoxia, microtubule in cardiac myocytes was depolymerized and Cx43 protein expression was reduced. Furthermore, Cx43 distribution was disorder which showing reduced at the intercalated disc and dispersively distributed in membranes. Pretreated with Taxol, microtubular depolymerization, Cx43 reduction and redistribution were inhibited in a dose dependent manner.CONCLUSION: Microtubular depolymerization and Cx43 redistribution induced by hypoxia were protected by low dosage of Taxol.Microtubule stabilizer may be acted as a new anti-arrhythmic agent.

Key words: Cardiac myocyte, Hypoxia, Microtubule, Gap junction, Taxol, Connexin