Effects of hyperbaric oxygen on the expression of caveolin-2 in brain tissues and the blood brain barrier after focal cerebral ischemia and reperfusion

Abstract

Objective To investigate the effects of hyperbaric oxygen (HBO) on the expression of caveolin2 and matrix-metalloproteinase-9 (MMP-9) in brain tissues and the blood brain barrier (BBB) after cerebral ischemia and reperfusion (I/R) in rats. Methods Three hundred and seventy male Wistar rats were randomly assigned into sham,ischemia-reperfusion,HBO,and I/R + HBO groups. After creating cerebral I/R models,oxygen at 0.25 MPa was administered 5 times,and 2％ Evans blue (EB) was injected into the tail veins 1 h before the rats were sacrificed.The permeability of the BBB,the expression of caveolin-2 and MMP-9,and EB content were determined by Western blotting,immunohistochemistry,and spectrophotometery,respectively. Results In the I/R group,the EB content increased steadily to a peak at 4 hours.EB content in the IR + HBO group was significantly lower than in the I/R group.Caveolin-2 and MMP-9 were significantly augmented by I/R injury at the 24th,48th and 72nd hours.Compared to the I/R group,HBO intervention decreased their expression levels. Conclusion HBO intervention can reverse the increase of caveolin-2 and MMP-9 caused by I/R injury,which suggests a mechanism for protective effects of HBO on the permeability of the BBB in I/R injury. Key words: Hyperbaric oxygen ; Ischemia-reperfusion ; Blood brain barrier; Caveolin-2 ; Matrix-met-alloproteinase-9