Abstract： Objective:To observe the preventive effects of pretreatment with Berberine（BBR）on pulmonary decompression injury，so as to explore the rapid intervention measures for emergency decompression exposure.Methods:Using the random number table method，a total of 50 healthy male SD rats were divided into five groups：control group，model group，and low，medium，and high dose BBR pretreatment groups. The rats of the three BBR pretreatment groups were intraperitoneally injected with 1 ml BBR solution with different concentrations of 12.5，25.0，and 50.0 mg/kg，respectively，three hours before pressurization. The control group and the model group were intraperitoneally injected with 1 ml normal saline. The control group rats were not treated with pressurization，while the rats in other four groups were treated with pressurization to 60 m within three minutes and continued for 60 minutes，and then rapidly decompressed to the normal atmospheric pressure within（30 ± 5）seconds at an even speed before exiting the chamber. The mortality rate of rats within 30 minutes after exiting the chamber was observed. The level of superoxide dismutase（SOD）in the homogenate of lung tissue was observed by enzyme-linked immunosorbent assay（ELISA），the level of malondialdehyde（MDA）was measured by the thiobarbituric acid（TBA）method，and the apoptosis was measured by immunohistochemistry and TUNEL assay.Results:The mortalities of the model group and the low，medium，and high dose BBR pretreatment groups were 50%，30%，30%，and 40%，respectively. Compared with the control group，the SOD level in the lung tissue of the model group rats was decreased significantly，and the MDA level was increased significantly（ P<0.05）. Specifically，the MDA level in the medium dose BBR pretreatment group was significantly increased，and the difference was statistically significant（ P<0.05）. Compared with the model group，the SOD levels of the low and high dose BBR pretreatment groups were significantly increased，while the MDA levels in both groups were significantly decreased，all with statistically significant differences（ P<0.05）. Compared with the low dose BBR pretreatment group，the medium dose BBR pretreatment group showed a significant decrease in SOD level and a significant increase in MDA level in lung tissue，and these differences were statistically significant（ P<0.05）. Compared with the control group，the lung tissue of the model group rats exhibited significant increase of interstitial hyperemia and edema. However，the interstitial hyperemia and edema in the BBR pretreatment groups were significantly milder than that of the model group，with statistically significant differences（ P＜0.05）. As the BBR dosage increased，the degree of interstitial hyperemia and edema decreased；the difference between the high dose BBR pretreatment group and the control group was not statistically significant（ P>0.05）. The cell apoptosis rate in the lung tissue of the model group rats was significantly higher，compared with the control group. The apoptotic rate in the low dose BBR pretreatment group was significantly lower than that of the model group. These differences were statistically significant（ P<0.05）. Conclusion:The BBR pretreatment can protect the lung tissue of rats from decompression injury by rapidly inhibiting the oxidative stress and reducing the apoptosis rate. The optimal preventive dosage needs further exploration. The degree of oxidative stress may serve as an early warning indicator for the degree of decompression injury.