Salvia Miltiorrhiza's Influence On Retinal Morphology And Function In Rats Of Simulated High Altitude Hypoxia

OBJECTIVE: To investigate the changes on retinal morphology and function in rats of simulated hypoxia at different altitudes by electroretinogram(ERG)and optical coherence tomography(OCT),then to evaluate the effects of Salvia Miltiorrhiza Injection.METHODS: Eighty 8-10 weeks old male Sprague-Dawley rats were randomly divided into intervention group and the control group,40 rats in each one.Intervention group rats were treated with 20 ml/kg dose of Danshen Injection by intraperitoneal injection,and the control group rats were injected with 0.9% Sodium Chloride Injection in the same dose.0.5 hours after injection,each group randomly selected 10 rats reared in plateau environment simulation experimental chamber,which simulated the altitudes of 1500 meters,3000 meters,5000 meters and 8000 meters in the experimental chamber,for 6 hours.Lighting for the frist 3 hours,then keep the chamber dark.After leaving the experimental chamber,anesthetized rats in the darkroom by red light,then checked up ERG and OCT examination,ERG was used to measure the amplitude and latency of a wave and b wave of the maximal combined reaction,and the amplitude of oscillatory potentials OPs2 was measured,the retinal thickness was measured by OCT.The data were processed with software SPSS.RESULTS: The changing of retinal thickness in rats was more notable with the increase of simulated altitude(P < 0.05).With altitude increasing the Max ERG a wave amplitude,b wave amplitude and the OPs2 wave amplitude decreased gradually(P < 0.05),and the Max ERG b wave latency time prolonged(P < 0.05),but the latency changes of a wave was not significant(P > 0.05).At the simulated hypoxia of 1500 meters,the ERG and OCT changes between intervention group and the control group was not obvious(P > 0.05),While at the simulated hypoxia of 3000 meters,5000 meters and 8000 meters,rat retinal thickness of the salvia miltiorrhiza intervention group was significantly lower than the saline control groups(P < 0.05),and the amplitude of OPs2 wave of the intervention group was significantly higher than the control group(P < 0.05).Compared with the control group and the intervention group,the difference of Max ERG a wave amplitude and latency,b wave amplitude and latency showed no statistically significant(P > 0.05).Underthe condition of simulated high altitude hypoxia,the retinal thickness showed negative correlation with the changes of the OPs2 wave amplitude(P < 0.05).CONCLUSION: Retinal morphology and function were both changed in rats of simulated high altitude hypoxia,with the increase of simulated altitude,retinal function in rats decreased and the retinal thickness increased.Salvia miltiorrhiza can preserve the damage in rat retina from high altitude hypoxia,this protective effect may be achieved by improving the blood circulation of the rat retina.ERG and OCT could serve as new objective indicators of the changes on retinal function and morphology by high altitude hypoxia.