The effect of red light on the expression of apoptosis factors during acute hypoxic-ischemic brain damage in neonatal rats

Objective To investigate the effect of red light on the expression of caspase-8 and caspase-3 mRNA and protein during the acute stage of hypoxic-ischemic brain damage (HIBD) in neonatal rats.Methods Forty-five seven-day-old Sprague-Dawley rats were randomly divided into a sham group,an HIBD model group (model group) and an irradiation group.The rats in the model and irradiation groups were subject to HIBD induced using the Rice-Vannucci method.The irradiation group was treated by irradiation with red light on the forehead immediately after the establishment of the HIBD model for 30 min/d on 3 consecutive days,while the sham group and the model group received no treatment.On the 3rd day after the operation,10 rats from each group were sacrificed by cervical dislocation and the left hippocampus was rapidly isolated and snap-frozen in liquid nitrogen for mRNA and protein examination.Another 5 rats in each group were used for immunofluorescence testing to localize and semi-quantify the expression of caspase-8 and caspase-3.Results In the model group,expression of caspase-8 and caspase-3 mRNA and protein in the left hippocampus was higher than in the sham group on the 3rd day.After red light irradiation,expression of caspase-8 and caspase-3 mRNA and protein decreased significantly in the irradiation group compared with the HIBD group.In the CA 1 region of the hippocampus,the levels of caspase-8 and caspase-3 in the irradiation group were significantly lower than in the model group.Conclusion Red light irradiation can decrease the expression of such apoptosis factors as caspase-8 and caspase-3 in hypoxic-ischemic brain damage at the acute stage and inhibit neural cell apoptosis so as to exert therapeutic effects for hypoxic-ischemic brain damage. Key words: Hypoxia;  Ischemia;  Brain damage;  Red light;  Apoptosis