ObjectiveTo observe the inflammatory cytokines expression of lung tissue and the changes of miR126a-5p and miR155-5p in septic mice after vitamin C(Vit C) intervention, and to analyze the potential protective mechanism of Vit C in the acute lung injury in sepsis.

MethodsA total of 18 male mice(4 to 6 weeks) were selected and randomly divided into the control group(CON), sepsis+NS group(SEP) and sepsis+Vit C intervention group(SEP+IR), before the injection of Vit C 1 000 mg/kg by tail vein for three consecutive days in the cecum puncture ligation model.Wet weight/dry weight(W/D) of lung tissue was measured 12 h after operation.HE staining was used to observe the pathological appearance of lung and the diameter of alveoli was measured.The changes of miR126a-5p and miR155-5p were detected by RT-qPCR, the protein expressions of Caspase 1 and Caspase 3 were detected by Western blot, and the expressions of IL-6 and TNF-α were detected by ELISA.

ResultsCompared with CON group, the W/D of lung in SEP group was increased and the alveolar aperture was decreased significantly in SEP group.The expressions of miR126a-5p, miR155-5p, Caspase 1 and Caspase 3 were increased in SEP group.Meanwhile, the inflammatory cytokines IL-6 and TNF-α were further increased(P<0.05).Compared with SEP group, SEP+IR group had lower W/D, higher alveolar pore size, lower expression in miR126a-5p, miR155-5p, Caspase 1 and Caspase 3.Vit C further inhibited the increase of inflammatory cytokines IL-6 and TNF-α(P<0.05).

ConclusionsVit C can reduce pulmonary edema and stabilize alveolar volume, which may be related to the decreased expressions of Caspase 1 and Caspase 3 induced by miR126a-5p and miR155-5p.