载脂蛋白E拟肽对实验性变态反应性脑脊髓炎小鼠基质金属蛋白酶-9和基质金属蛋白酶组织抑制因子-1表达的影响

目的探讨载脂蛋白E(Apo E)拟肽对实验性变态反应性脑脊髓炎(EAE)小鼠基质金属蛋白酶-9(MMP-9)和基质金属蛋白酶组织抑制因子-1(TIMP-1)表达的影响。方法将30只雌性C57BL/6J小鼠随机分为Apo E拟肽组、EAE组和正常组,每组10只小鼠。EAE模型通过以髓鞘少突胶质细胞糖蛋白多肽35-55为抗原诱导。Apo E拟肽组在免疫后第2 d到30 d每隔2 d按5 mg/(kg·d)背部皮下注射Apo E拟肽。EAE组和正常组均以等体积生理盐水替代。免疫后第0~35 d每日对小鼠进行神经功能评分。免疫后第35d解剖小鼠,分离大脑和脊髓并行HE染色。采用免疫组化染色法检测各组小鼠大脑、脑干和脊髓的MMP-9和TIMP-1的表达。结果正常组小鼠均未发病。Apo E拟肽组、EAE组的小鼠全部发病,但各有1只小鼠发病后死亡。Apo E拟肽组与EAE组的发病潜伏期差异无统计学意义(P=0.72)。Apo E拟肽组的神经功能评分在峰值和慢性期(第35 d)均明显低于EAE组(均P0.05)。HE染色示,正常组未见炎症细胞浸润;EAE组小鼠大脑、脑干和脊髓均有不同程度的炎性细胞浸润,以脑干和脊髓较为明显;Apo E拟肽组小鼠CNS炎性细胞浸润相对于EAE组明显减少。EAE组小鼠大脑、脑干和脊髓的MMP-9表达均高于正常组(均P0.05)。Apo E拟肽组小鼠大脑和脊髓的MMP-9表达要明显低于EAE组(均P0.05),其中Apo E拟肽组小鼠中脑和脊髓的MMP-9表达与正常组相比无明显差异(均P0.05)。正常组小鼠脊髓TIMP-1的表达明显高于EAE组和Apo E拟肽组(均P0.05)。而Apo E拟肽组与EAE组小鼠大脑、脑干和脊髓TIMP-1表达的差异均无统计学意义(均P0.05)。结论 Apo E拟肽能通过抑制大脑和脊髓MMP-9的表达改善EAE小鼠的症状。

Effects of Apolipoprotein E-mimetic peptides on the expressions of matrix metalloproteinase-9 and matrix metalloproteinase tissue inhibitor-1 in mice with experimental autoimmune encephalomyelitis

Objective To explore the effects of Apolipoprotein E-mimetic peptides on the expressions of matrix metalloproteinase-9 ( MMP-9) and matrix metalloproteinase tissue inhibitor-1 ( TIMP-1 ) in mice with experimental autoimmune encephalomyelitis ( EAE).Methods Thirty female C57BL/6J mouse were randomly divided into 3 groups:ApoE-mimetic peptides-treated group, EAE group and health group, with 10 mouse in each group.The EAE model was induced in mice using myelin oligodendrocyte glycoprotein peptides 35-55.ApoE-mimetic peptides-treated mice were subcutaneously injected 5 mg/( kg· d) ApoE mimetic peptide every 2 d from immunization 2 d to 30 d. EAE group and normal group replaced with an equal volume of saline injections.The neurological function of mice were scored daily after immunization 0 d to 35 d.Mice were dissected after immunization 35 d, the brain and spinal cord were collected and their expressions of MMP-9 and TIMP-1 were detected using immunohistochemistry.Results The health group had no sick mice.Whole EAE mice were illness in ApoE-mimetic peptides-treated group and EAE group, and the two groups each had a death after the onset.The latency difference between ApoE peptide group and EAE group was not statistically significant (P=0.72).The peak and chronic phase (35 d) neurological scores of ApoE mimetic peptide group were significantly lower than EAE group (all P<0.05).HE staining showed normal group had no inflammatory cell infiltration.The brain, brain stem and spinal cord of EAE suffered varying degrees of inflammatory cell infiltration, which was more obvious in brain stem and spinal cord.ApoE peptide-treated group showed significantly reduced CNS inflammatory cell infiltration campared to EAE group.The MMP-9 expression of brain, brain stem and spinal cord in EAE group was significantly higher than health group ( all P<0.05 ) .The MMP-9 expression of brain and spinal cord in ApoE mimetic peptide group was significantly lower than EAE group ( all P<0.05 ) , and was not significantly different with the health group ( all P>0.05 ) .The spinal TIMP-1 expression in health group was significantly higher than EAE group and ApoE mimetic peptide group respectively ( all P<0.05) .The brain stem and spinal cord TIMP-1 expression in ApoE peptide group was not statistically different with EAE group ( all P>0.05 ) .Conclusion ApoE-mimetic peptides can protect against EAE in mice through inhibiting the expression of MMP-9 in brain and spinal cord.