Objective      To observe the expression of microtubule-associated protein 4 (MAP4) in epidermal cell line (HaCaT cells)

and the effect of MAP4 on cell migration under hypoxic microenvironment.       Methods      All experiment samples were divided into 3 groups: HaCaT cell group

RNAi-MAP4 cell group and con-RNAi-HaCaT cell group. We detected the expression of MAP4 in HaCaT Cells under different hypoxic microenvironment (1% O

2

for 0.5

1 and 3 h

respectively) by Western b

lotting. Besides

we observed the expression of α-tubulin

an important component of cytoskeleton by fluorescence immunoassay. In addition

the migration of HaCaT cells was observed by in vitro cell scratch experiment.        Results      (1) The expression of MAP4 in HaCaT cells was increased after hypoxia (0.5 h) and decreased rapidly with the duration of hypoxia (1 h and 3 h ). (2) In the early period of hypoxia

microtubule dynamics of different cells in each group was changed. The cytoskeleton became depolymerized

showing a tendency to migrate. (3) The migration ability of normal HaCaT cells and con-RNAi-HaCaT cells significantly increased after 24 h under hypoxic microenvironment (

P

0.05). Under normoxia

the migration of RNAi-HaCaT cell was poorer than that of HaCaT cells and con-RNAi-HaCaT cells (

P

0.01)

and not increased after hypoxia.       Conclusion      The hypoxic microenvironment can enhance the migration ability of HaCaT cells by regulating MAP4 expression.