Research On Toll-like Receptors4with Acute Lung Injury In Lupus With Atherosclerotic Mice

ObjectiveCurrent studies and our previous work have provedLipopolysaccharide(LPS)-induced lupus is a well-established model of murine lupuswhich develops lupus-specific autoantibodies and glomerulonephritis. However, themechanism of lung injury in lupus with atherosclerotic(AS) mice is not so clear.Therefore, we aimed to investigate the pathologic mechanisms of TLR4in lung injuryafter TLR4agonists（LPS） and/or TAK-242（TLR4antagonist）were administeredto ApoE-/-and C57BL/6mice.MethodsForty female ApoE-/-mice aged9-10weeks were randomized into4groups,10ineach group. Saline (isovolumic normal saline), LPS(2.5mg/kg), TAK-242(0.3mg/kg),LPS+TAK-242(LPS2.5mg/kg and TAK-2420.3mg/kg) were administeredrespectively by intraperitoneal injection, twice a week. Corresponding interventionswere given to C57BL/6mice and compared with ApoE-/-ones. After4weekstreatment,plaque area and quantitative analysis of plaque area percentage in aorticsinus serial frozen sections were determined by Hematoxylin-Eosin(HE) and oil red Ostaining. Lung pathomorphology changes were determined by HE、Masson andHemosiderin staining in paraffin sections. In addition, the serologic antinuclearantibody(ANA), anti-double-stranded DNA (anti-dsDNA) and inflammatorycytokines such as interferon-gamma(IFN-), tumor necrosis factor(TNF-),interleukin-1(IL-1) were measured by enzyme-linked immunosorbnentassay(ELISA). TLR4and NF-κB p65(nuclear factor-kappa B p65) mRNAexpressions in lung were detected by real time-PCR. Protein expressions of TLR4,NF-κB p65and B cell activating factor belonging to the TNF family(BAFF) in lungwere examined by immunohistochemistry. So were TLR4and BAFF in aortic sinusspecimens.Results1. The levels of ANA, anti-dsDNA and immune inflammatory mediators (IFN-, TNF-, IL-1) rosed significantly in ApoE-/-and B6mice. However, theabove-mentioned parameters were more obvious in ApoE-/-than in B6mice（P0.01）.2. In ApoE-/-mice, marked AS plaques were found in aortic sinus, accompanied bydifferent levels of inflammatory cell infiltration in vascular adventitia and plaques.Meanwhile, TLR4and BAFF increased significantly in plaques of ApoE-/-mice.3. In both ApoE-/-and B6mice, pulmonary capillaritis and interstitial fibrosisoccurred. Macrophages,neutrophils,lymphocytes and eosinophils arose aroundvessels and bronchi. Simultaneously, TLR4,NF-κB p65and BAFF expressions inlung were enhanced. However, the aforementioned manifestations were moreserious in ApoE-/-than in B6mice（P0.01）.4. TAK-242could evidently reduce the serum autoantibody levels, ameliorateatherosclerotic inflammatory response and lung tissue remodeling.5. TAK-242could significantly down-regulate the expression of TLR4,NF-B P65and BAFF in lung tissue and TLR4、BAFF in plaque.Conclusions1. At the early stage,acute inflammatory response occurred in vessel and lung inApoE-/-mice after LPS exposure. But systemic inflammation response syndromedid not develop.2. TLR4receptor revealed an important role in immune and inflammatory injury ofvessels and lung.3. TLR4inhibitors can significantly reduced autoimmune response and organdamage of ApoE-/-mice after LPS stimulation.4. TAK-242could inhibit the activation of TLR4/NF-kb signal pathway.