OBJECTIVETo observe the effects of hemoperfusion on oxidative stress status and the levels of matrix metallo proteinase (MMP-2, MMP-9), tissue inhibitor of metalloproteinase (TIMP-1) in lungs, livers and kidneys in paraquat poisoning rabbits, and to explore the mechanism of therapeutic effects induced by HP on acute paraquat poisoning.

METHODSSeventy eight rabbits were randomly divided into normal control group (N group, n=6), exposure groups (PQ group, n=24), hemoperfusion treatment group (HP treatment group, n= 24) and blank control group (HP group, n=24). The PQ, HPQ and HP groups were divided into 4 observation time groups (1, 3, 7 and 21 d). N group was exposed to 5 ml normal saline and PQ group was exposed to 50 mg/kg PQ by oral gavage. In 1 h after PQ exposure, HPQ group was exposed to the activated carbon hemoperfusion for 2 h. The content or activity of MDA, SOD and GSH-Px in lungs, livers and kidneys were detected, the expression levels of MMP-2, MMP-9 and TIMP-1 were measured with immunohistochemical SP method for all groups.

RESULTSThe contents of MDA in lungs, livers and kidneys of PQ and HPQ groups decreased and the activities of SOD and GSH-Px in lungs, livers and kidneys of PQ and HPQ groups increased with observation time. The expression levels of MMP-2, MMP-9 and TIMP-1 in PQ and HPQ groups enhanced on the first day, PQ group was most obvious. Along with the observation time extended, all kinds of positive expression were still high. Compared with normal control group, the activities of serum SOD and GSH-Px in PQ and HPQ groups declined significantly, but the contents of serum MDA increased; the expression levels of MMP-2, MMP-9 and TIMP-1 in lung, liver and kidney tissues increased obviously, the ration between MMP-9 and TIMP-1 significantly increased (P < 0.05). Compared with PQ group, the activities of SOD and GSH-Px in HPQ group significantly increased, the content of MDA declined, the expression levels of MMP-2, MMP-9 and TIMP-1 in lung, liver and kidney tissues declined obviously, the ration between MMP-9 and TIMP-1 significantly declined, but higher than N group, the differences were statistically significant (P < 0.05).

CONCLUSIONThe oxidative stress and MMPs may be involved in the pathogenesis of tissue injuries induced by paraquat. The treatment with HP could obviously reduce oxidative stress and the expression levels of MMP-2, MMP-9 and TIMP-1, enhance the ration between MMP-9 and TIMP-1. So HP treatment could play a role in rescuing the PQ poisoning and protecting the organs function.