Abstract: ObjectiveTo explore the influence of UVB irradiation on oxidation damage of experimental silicosis rat. MethodsThirty two SD rats were randomly divided in to four groups.Rats in the experiment were injected with SiO₂ and irradiated with UVB.The rats were killed and their blood and lung tissue were collected.The contents of SOD,MDA and HYP in 10% homogenate of lung tisue and the contents of CP in serum were detected by colourometry.Body weight gain and organ weights were determined.ResultsAfter in jecting SiO₂ ,the activities of SOD in lung tissues homogenate were decreased(P<0.01)and the contents of HYP of lung were increased(P<0.01).After injecting SiO₂,the serum CP activities and the contents of HYP were higher than non injected rats(P<0.05).After irradiated with UVB,the activities of SOD in lung tissues homogenate were decrea sed(P<0.01).The changes of MDA ,HYP and CP were not statistically significant(P>0.05).After the exposure of UVB and silica particles,SOD and HYP in lung tissue homogenate and CP in serum showed interaction with the exposure(P<0.01).MDA in lung tissues homogenate showed interactions with the treatment(P<0.05).ConclusionSiO₂ has oxidation effect on pumlonary tissue of experimental silicosis rats and can cause pumlonary fibrosis.But UVB exposure could decrease the oxidation effect and mitigate pumlonary fibrosis.