摘要Background Medical ozone therapy system was reported to have certain effects on the treatment of severe hepatitis,but its mechanism is not very clear. One of the causes of death of severe hepatitis is complication of renal damage or hepatorenal syndrome. The present study aimed to observe effects of medical ozone therapy system on plasma renin activity (PRA), angiotensin Ⅱ (AⅡ), aldosterone (ALD), renal blood flow and renal function of patients with chronic severe hepatitis and explore mechanisms of medical ozone therapy in the treatment of severe hepatitis.Methods Eighty-five cases with chronic severe hepatitis were randomly divided into ozone therapy group (43 cases)and control group (42 cases). The patients in the ozone therapy group were treated with basic treatments plus ozone therapy system. Basic autohemotherapy was used. One hundred milliliter venous blood was drawn from each patient,and was mixed with 100 ml (35 μg/ml) medical ozone and then was returned the blood to the patient intravenously, once every other day for 20 days. Only the basic treatments were given to the control group. PRA, All, ALD, renal blood flow and damage to renal function of the two groups before treatment and 20 days after treatment were compared. Survival rates were also compared.Results Twenty days after the treatment, in ozone therapy group, PRA was (1.31±0.12) ng·ml-1·h-1, All (111.25±17.35)pg/ml, ALD (251.31 ±22.60) pg/ml, which decreased significantly compared with those before treatment (PRA (2.23±0.13)ng·ml-1 ·h1, AⅡ (155.18±19.13) pg/ml, ALD (405.31±29.88) pg/ml, t=4.67-14.23, P <0.01), also lower than those of control group 20 days after the treatment (PRA (2.02±0.11) ng·ml-1·h-1, All (162.21±15.32) pg/ml, ALD (401.20±35.02) pg/ml,t=4.97-15.61, P <0.01); renal blood flow was (175.15±28.20) ml/min, which increased compared with that before the treatment ((125.68±21.25) ml/min) and was higher than that of control group 20 days after the treatment ((128.59±23.15)ml/min, t=4.78, 4.61, P <0.01). Renal damage occurred in 2 cases (5%) in ozone therapy group, less than that in control group (9 cases, 21%) (X2=5.295, P <0.05). Thirty-three cases (77%) in ozone therapy group vs. 16 cases (38%) in control group survived (X2=12.993, P<0.01).Conclusions Basic treatment plus medical ozone therapy for patients with chronic severe hepatitis could decrease PRA, All and ALD levels significantly increase renal blood flow, prevent renal damage to certain extent and improve survival rate of the patients.