Experimental research on the effect of hyperbaric oxygen therapy at different intervention time on cerebral ischemia in rats

Abstract

Objective To investigate the effect of hyperbaric oxygen (HBO) at different intervention time with different treatment courses on cerebral ischemia in rats with middle cerebral artery occlusion(MCAO), so as to provide clues and evidences for further exploration of HBO in the treatment of hypoxic-ischemic encephalopathy. Methods Sixty SD rats with MCAO were divided into 2 groups: the control group that did not receive HBO therapy and the observation group that received HBO therapy. The 2 groups of MCAO rats were divided into 5 subgroups in accordance with different intervention time, i. e. the MCAO 3 h group, the MCAO 6 h group, the MCAO 24 h group, the MCAO 4 d group, and the MCAO 7 d group, each consisting of 6 rats. The animals in the observation group received HBO therapy once a day, 10 days a treatment course. Effects of HBO were observed at 4 different time points: before treatment, at day 10, day 20 and day 30 after treatment. Rogers DC and Hunter AJ 7-point scoring method was used to evaluate the treatment and observe the neurological function of the rats. Results (1)With regard to different intervention time, statistical significance could be observed in the neurological function scores of the HBO 30 d observation subgroup, as compared with those before treatment, 10 and 20 days after HBO therapy (P<0.05). (2)With regard to different treatment courses, Statistical significance could be noted in the neurological function scores(2.67±0.12, 3.50±0.41, 4.17±0.26)for the MCAO3h, MCAO6h and MCAO24h observation subgroups at day 10 after treatment, as compared with those of the control group(5.67±0.32, 5.50±0.21, 5.83±0.11)(P<0.05). Statistical significance was noted in the neurological function scores(2.17±0.15, 3.00±0.33, 3.83±0.25, 6.00±0.34) for the MCAO 3 h, MCAO 6 h, MCAO 24 h and MCAO 4 d observation subgroups at day 20 after treatment, as compared with those of the control group(6.67±0.11, 6.17±0.23, 6.17±0.13, 6.67±0.19)(P<0.05). Statistical significance could also be seen in the neurological function scores(1.67±0.18、2.17±0.21、3.67±0.28、6.33±0.32)for the MCAO 3 h, MCAO 6 h, MCAO 24 h and MCAO 4 d observation subgroups at day 30 after treatment, as compared with those of the control group(6.83±0.16、6.67±0.12、6.50±0.23、6.83±0.15)(P<0.05). Conclusions HBO therapy could significantly decrease the neurological function scores and improve the neurological function of the MCAO rats. The earlier the intervention time of HBO and longer the treatment course, the less severe neurological function lesion would be sustained in the MCAO rats. Key words: Cerebral ischemia; Hyperbaric oxygen; Intervention time; Treatment course