| Objective:To investigate the expression of HSP22 in the brain of type 2 diabetic mice,and evaluate the effect of HSP22 on central nervous system inflammation,oxidative stress and the damage of brain tissue.Methods:(1)The first part: thirty 8-9 weeks-old,wild,C57BL/6 male mice were randomly divided into normal group,high-fat group and diabetes group;the second part: twenty wild C57BL/6 male mice and twenty HSP22 overexpression transgenic C57BL/6 male mice were randomly divided into wild normal group,wild diabetes group,transgenic normal group,and transgenic diabetes group.The high-fat diet combining with intraperitoneal injection of streptozotocin(STZ)was used to induce a mice model of The type 2 diabetes.(2)The protein expression of HSP22,NLPR3,Caspase1,TNF-α and Active-Caspase-3 in brain were measured by Western Blot.(3)The expression of IL-1β and IL-18 in brain were measured by PCR.(4)The activities of SOD,GSH-PX,and the content of MDA were measured by chromatometry.(5)The HE staining was used to observe the histopathological changes in the brain.Results:(1)The changes of fasting blood glucose levelThe baseline fasting blood glucose shows no difference in all groups(P>0.05).After intraperitoneal injection of STZ,the fasting blood glucose in the diabetic group was significantly higher than that in the normal group and the high-fat group(P<0.01).The fasting blood glucose level in the normal group and the high-fat group mice were not statistically different(P>0.05);The fasting blood glucose in the wild diabetes group and transgenic diabetes group was significantly higher than that in the wild normal group and transgenic normal group(P<0.01).The fasting blood glucose in the transgenic diabetes group was lower than that in the wild diabetes group(P<0.01).There was no significant difference in fasting blood glucose levels between the wild normal group and the transgenic normal group(P>0.05).(2)The protein expression of HSP22,NLPR3,Caspase1,TNF-α and Active-Caspase-3 in brain were measured by Western Blot.In normal group,high-fat group,and diabetic group: the expression of HSP22,NLPR3,Caspase1,TNF-α,and Active Caspase-3 in diabetic group was higher than that in normal group and high-fat group,with statistical significance(P<0.05).There was no significant difference in the expression of HSP22,NLPR3,Caspase1,TNF-α and Active-Caspase-3 between the normal group and the high-fat group(P>0.05).In wild normal group,wild diabetes group,transgenic normal group,and transgenic diabetes group: compared with the wild normal group,the expression of HSP22 protein in the wild diabetes group,the transgenic normal group,and the transgenic diabetes group were increased(P<0.05);HSP22 protein expression was significantly higher in the transgenic diabetes group than that in the wild diabetes group and the transgenic normal group(P<0.05);there was no significant difference between the wild diabetes group and the transgenic normal group(P>0.05);There were no significant difference in the protein expression of NLPR3,Caspase1,TNF-α and Active-Caspase-3 among wild normal group and transgenic normal group(P> 0.05);The protein expression of NLPR3,Caspase1,TNF-α,and Active-Caspase-3 in wild and transgenic diabetes group was higher than that in wild and transgenic normal group(P<0.05).The protein expression of NLPR3,Caspase1,TNF-α and Active-Caspase-3 in transgenic diabetes group was lower than that in wild diabetes group(P<0.05).(3)The expression of IL-1β and IL-18 in brain was measured by PCR.In normal group,high-fat group and diabetic group:the expression of IL-1β and IL-18 mRNA in diabetic group was higher than that in normal group and high-fat group(P<0.05);There was no significant difference in the expression of IL-1β and IL-18 mRNA among normal group and high-fat group(P>0.05).In wild normal group,wild diabetes group,transgenic normal group,and transgenic diabetes group: there was no significant difference in the expression of IL-1β and IL-18 mRNA among wild normal group and transgenic normal group(P>0.05).The expression of IL-1β and IL-18 mRNA in the wild and transgenic diabetes groups was higher than wild and transgenic normal groups(P<0.05);the level of IL-1β and IL-18 mRNA in transgenic diabetes group were lower than that in wild diabetes group(P<0.05).(4)The activities of SOD,GSH-PX,and the content of MDA were measured by chromatometry.In normal group,high-fat group and diabetic group:the activity of SOD and GSH-PX in diabetic group was lower than that in normal group and high-fat group(P<0.05).There was no significant difference in the activity of SOD and GSH-PX activity among normal group and high-fat group(P> 0.05);MDA content in diabetic group was higher than normal group and high-fat group,with statistical significance(P<0.05);MDA content had no significant difference among normal group and high-fat group.(P> 0.05).In wild normal group,wild diabetes group,transgenic normal group,and transgenic diabetes group: there was no significant difference in the activity of SOD and GSH-PX activity and the content of MDA among wild normal group and transgenic normal group(P>0.05);the activity of SOD and GSH-PX in the wild and transgenic diabetes groups was lower than wild and transgenic normal groups(P<0.05);the activity of SOD and GSH-PX in transgenic diabetes group were higher than that in wild diabetes group(P<0.05);MDA content in the wild and transgenic diabetes groups was higher than wild and transgenic normal groups(P<0.05);MDA content in transgenic diabetes group were lower than that in wild diabetes group(P<0.05).(5)histopathological observationHE staining of mouse brain showed that neurons in the hippocampal CA1 region had normal structure,clear nucleoli,regular arrangement in normal group;the neuron structure was almost normal,and little neuronal apoptosis in the high-fat group;a large number of neuronal cell in the hippocampal CA1 region were suffered nuclear condensation,chromatin condensation,deep staining,disordered arrangement in diabetes group;the cell degeneration and necrosis and the disordered arrangement of neurons in hippocampal CA1 region were improved in transgenic diabetes group.Conclusion:1)the neuroinflammation reaction,oxidative stress,and tissue damage were increased in the brain of the type 2 diabetic mice.2)The expression level of HSP22 in brain of the type 2 diabetic mice was significantly increased.3)Over-expression of HSP22 can inhibits CNS inflammatory responses,oxidative stress,and improves the brain damage in the type 2 diabetic mice. |
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