<正>Objective: To determine whether AQP4 expression is associated with lactate （Lac） and Nacetyl aspartate （NAA） and with apparent diffusion coefficient （ADC） abnormality after rat cerebral ischemia. Methods: The time courses of ADC and lactate and NAA assessed by proton magnetic resonance spectroscopy （HMRS） were investigated at the time point of 6 h

and 1

3

7 d after rat cerebral ischemia induced by middle cerebral artery occlusion. Expression of AQP4 mRNA and protein were measured using RT-PCR and Western blot analysis respectively. Results: Significant reductions of NAA concentration and increases of lactate concentration were found after rat cerebral ischemia. The expressions of AQP4 mRNA and protein were increased at 6 h

and reached the peak at 1-3 d

then began to decrease at 7 d after rat cerebral ischemia. The expression of AQP4 was significantly correlated with NAA（rRT = - 0. 856

rw = - 0.927

P<0. 01）

and with lactate （rw = 0. 473

rRT = 0. 413

P<0. 05）

and with ADC values during the period of 1-7 d after rat cerebral ischemia （rw = 0. 984

rRT= -0. 925

.P<0. 05）. In addition

correlations between Lac and the ADC values（r= - 0. 677

P<0. 05）and between NAA and ADC values during the period of 1-7 d after rat cerebral ischemia （r=0. 909

P<0. 05） were also observed. Conclusion: The data suggest that AQP4 is involved in the transport of water when brain edema is formed and cell membrane integrity is lost.