ABSTRACT
[Objective]To investigate the effects of ghrelin on inflammatory signaling protein kinase B(Akt),nuclear factor-κB(NF-κB)and inducible nitric oxide synthase(iNOS)in alveolar macrophage(AM).[Methods]24 Male SD rats were randomly divided into Sham,CLP,CLP+ghrelin,and Sham+ghrelin groups. Cecal ligation and puncture(CLP)was used to induce sepsis. Ghrelin(20 nmol/kg)was administered by intraperitoneal injection at 3 h and 15 h post-operation. Histopathological changes of lungs were observed and scored.AM were extracted from bronchoalveolar lavage fluid(BALF). Interleukin-1β(IL-1β),tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6)in BALF were detected by ELISA. IL-1β,TNF-α,and IL-6 mRNA in AM were detected by qPCR.NF-κB p65,IκBα,p-IκBα,Akt,p-Akt and iNOS in AM were detected by immunofluorescence(IF)and Western blotting.[Results]The histologic score(6.7±0.8),BALF IL-1β[(146±12)pg/mL]and IL-6[(182±10)pg/mL]from CLP+ghrelin group were respectively 35.4%,44.5% and 46.42% lower than those from CLP group[(10.3±0.7),(263±17)pg/mL,and(273±5)pg/mL],P<0.05.No significant difference was found in BALF TNF-α between CLP group and CLP+ghrelin group.The IL-1β,TNF-α and IL-6 mRNA in AM from CLP+ghrelin group were respectively 54.38%,53.6% and 46.42% lower than those from CLP group,P<0.05. The nuclear NF-κB p65 and cytoplasmic p-IκBα,p-Akt and iNOS from CLP+ghrelin group were respectively 32.58%,45.42%,27.6% and 48.33% lower than those from CLP group,P<0.05. There was no significant difference in all data between Sham group and Sham+ghrelin group.[Conclusion]Ghrelin can decrease the activity of inflammatory signaling proteins Akt,NF-κB and iNOS in AM,therefore restricts AM expressing pro-inflammatory cytokines IL-1β,TNF-α,and IL-6,thus alleviates sep-sis-induced acute lung injury(ALI).