Objective:To study the effect of inhibiting high mobility group box 1 (HMGB1) gene expression on ultrasonic blood flow characteristics, inflammatory response and apoptosis in diabetic retinopathy rats. Methods:Male SD rats were chosen and randomly divided into control group, model group and HMGB1 inhibition group, the latter two groups were given intraperitoneal injection of streptozotocin to establish the diabetes model, and HMGB1 group were given tail vein injection of HMGB1-shRNA lentivirus for intervention. The peak end-systolic velocity (PSV), peak end-diastolic velocity (EDV), resistance index (RI) and pulsatility index (PI) of central retinal artery as well as the HMGB1, bcl-2, bax and cleaved caspase-3 expression and TNF-α, MCP-1 and ICAM-1 contents in retinal tissues were measured at 4 weeks after intervention. Results:The PSV and EDV levels as well as bcl-2 expression in the model group were lower than those in the control group, while the RI and PI levels as well as HMGB1, bax and cleaved caspase-3 expression and TNF-α, MCP-1 and ICAM-1 contents were higher than those in the control group; the PSV and EDV levels as well as bcl-2 expression in the HMGB1 inhibition group were higher than those in the model group, while the RI and PI levels as well as HMGB1, bax and cleaved caspase-3 expression and TNF-α, MCP-1 and ICAM-1 contents were lower than those in the model group. Conclusion:Inhibition of HMGB1 gene expression can improve the blood flow of central retinal artery and inhibit the inflammatory response and apoptosis in diabetic retinopathy rats.