Effects of subcutaneous and intraperitoneal administration of insulin to KK mice's oxygen free radicals metaholism

Objective To observe the subcutaneous and intraperitoneal insulin injection's effect of the level of oxygen free radicals of type 2 diabetes model.Methods C57BL/6J mice were chosen as normal control group (C group,n=9).KK mice were randomly divided into intraperitoneal injection of insulin group (i.p.group,n=9),the subcutaneous insulin group (s.c.group,n=9) and untreated group (U group,n =9).The i.p.group and the s.c.groups were given certain amount of insulin (insulin injecta and protamine insulin injecta by volume ratio of 2:1 mixture)for one month,maintained the GLU at normal levels (6±1.5) mmol/L.SOD,GSH-PX activity and MDA content of serum,liver,kidney and heart in each group were detected.Results The liver,kidney,heart and serum's SOD and GSH-PX activity significantly reduced and MDA content significantly increased in the U group.Both kinds of delivery methods could increase serum SOD and GSH-PX activity and reduce the content of MDA to the normal control group level,but the intraperitoneal injection had stronger effect.Two kinds of delivery methods could both reduce the MDA content of liver,and had almost the same effect; but the subcutaneous injection group had better effect on increasing the liver's SOD activity,and the intraperitoneal injection had better effect on increasing liver's GSH-PX activity.Intraperitoneal injection had better effect on reducing kidney' s MDA content and increased SOD activity.Two kinds of delivery methods had the same effect on reducing the heart's MDA content.Conclusion The two delivery methods can both make the MDA levels of KK mice in serum,heart,liver and kidney fall to as normal as that of control group,but the two delivery methods have different ways of improving the antioxidant capacity in different organs.Intraperitoneal injection can reduce MDA content in serum and kidney better. Key words: Diabetes; Insulin; Oxygen free radicals