破骨细胞抑制凝集素相关蛋白2对小鼠内毒素血症的保护作用

Osteoclast inhibitory lectin related protein 2 protects mice from endotoxemia

目的：研究重组破骨细胞抑制凝集素相关蛋白2胞外段蛋白（OCILRP2-Fc）阻断OCILRP2受体信号对LPS诱导的内毒素血症的影响，探讨OCILRP2受体在机体炎症反应中的作用。方法荧光定量RT-PCR检测LPS刺激前后OCILRP2在RAW264．7细胞的表达；小鼠腹腔注射20mg/kg体重的LPS诱导内毒素血症的发生，分析OCILRP2-Fc对内毒素血症小鼠存活率的影响；称量小鼠脾脏重量分析脾脏充血肿大情况；HE染色观察肺脏、肝脏组织病理损伤情况；ELISA检测小鼠血清中炎症性细胞因子的水平；Westernblot检测LPS刺激前后巨噬细胞中NF-κB的活化。结果荧光定量RT-PCR结果表明LPS刺激显著提高了OCILRP2在小鼠巨噬细胞的表达（P＜0．05）；与对照组相比，OCILRP2-Fc可以显著提高内毒素血症小鼠的存活率；减轻小鼠脾脏肿大程度和内毒素血症对肺脏和肝脏组织造成的病理损伤；降低血清中细胞因子IL-6、IL-12、TNF-α和IFN-γ的浓度（P＜0．05）。Westernblot结果表明OCILRP2-Fc抑制LPS诱导的RAW264．7细胞内IκB的降解和NF-κBp65的磷酸化。结论采用OCILRP2-Fc阻断OCILRP2受体信号，减轻了小鼠内毒素血症对机体造成的炎症性损伤，提示OCILRP2在LPS诱导的炎症反应发生过程中具有促进作用。

Objecitv e To investigate the effects of a recombinant protein osteoclast inhibitory lectin related protein 2（ OCILRP2）-Fc on LPS-induced endotoxemia by blocking OCILRP 2 signaling pathway and to in-vestigate the roles of OCILRP2 during inflammation.Methods Real-time PCR was used to detect OCILRP2 ex-pression at mRNA level in RAW264.7cells before and after in vitro stimulation with LPS.A mouse model of en-dotoxemia was established by intraperitoneal injection of BALB /c mice with a median lethal dose of LPS .Two hours prior to LPS treatment, mice were intraperitoneally injected with OCILRP2-Fc, human IgG or PBS, re-spectively .Several parameters including the survival rate of BALB/c mice with and without LPS treatment , spleen weight for arterial hyperemia analyzing , histopathological changes of lung and liver by HE staining , serum levels of inflammatory cytokines （IL-6, IL-12, TNF-αand IFN-γ）by ELISA , NF-κB activity by Western blot, were analyzed .Results Real-time PCR showed that LPS elevated in vitro OCILRP2 expression at mRNA level in macrophages （P〈0.05）.Upon the treatment of OCILRP2-Fc, BALB/c mice suffered from endotoxemia showed obviously increased survival rate , decreased spleen hyperemia , attenuated pathological injury of lung and liver, reduced levels of IL-6, IL-12, TNF-αand IFN-γin serum samples （P 〈0.05） as compared with mice treated with human IgG and PBS .LPS induced NF-κB p65 phosphorylation and IκB degradation were inhibited by OCILRP2-Fc treatment.Conclusion OCILRP2-Fc protects mice from endotoxemia by blocking OCILRP 2 signaling, which suggests that OCILRP2 plays an important role in LPS induced inflammation.