【Animal modeling】-The protective effect of etomidate on acute lung injury in septic shock rats based on TLR4 pathway

  Objective To investigate the protective effect of etomidate (Eto) on acute lung injury in rats with septic shock based on the Toll-like receptor 4 (TLR4) pathway.

  Methods Seventy-five rats were randomly divided into sham operation group, model group, model-lipopolysaccharide (LPS) group, model-Eto group, and model-Eto-LPS group, with 15 rats in each group. Except for the sham-operated group, the other groups were treated with cecal ligation and puncture to replicate the septic shock rat model, and the sham-operated group only underwent laparotomy. Thirty minutes before surgery, the model-LPS group was intraperitoneally injected with LPS 15 mg/kg, the model-Eto group was intraperitoneally injected with etomidate 60 mg/kg, and the model-Eto-LPS group was also intraperitoneally injected with etomidate 60 mg/kg+LPS 15 mg/kg, the model group and the sham-operated group were intraperitoneally injected with normal saline. The levels of serum endotoxin (ET), IL-1β, IL-6 and TNF-α in BALF were detected 5 h after operation, the pathological changes of lung tissue were observed, and TLR4, myeloid differentiation factor (MyD88), nuclear factor in lung tissue were detected. -κB p65 (NF-κB p65) mRNA and protein expression.

  Results Compared with the sham operation group, the model group, model-LPS group, model-Eto group, model-Eto-LPS group had higher levels of ET and IL-1β, IL-6 and TNF-α in BALF, among which model- Eto group<model-Eto-LPS group<model group<model-LPS group (P<0.05). HE staining showed that the alveoli in the model group and model-LPS group were significantly congested, the alveolar wall and pulmonary interstitium were thickened, and a large number of inflammatory cells infiltrated, and the lesions in the model-LPS group were more serious; model-Eto group and model-Eto-LPS group The lesions were alleviated in all groups, with occasional alveolar capillary congestion and inflammatory cell infiltration, and the reduction was more obvious in the model-Eto group. Compared with the sham operation group, the relative expression levels of TLR4, MyD88, NF-κB p65 mRNA and protein in the lung tissue of the model group, model-LPS group, model-Eto group and model-Eto-LPS group were higher, and the model-Eto Group<model-Eto-LPS group<model group<model-LPS group (P<0.05).

  Conclusion Eto has a protective effect on acute lung injury in septic shock rats, which may play a regulatory role by inhibiting the TLR4 pathway.