OBJECTIVE To investigate the effects of camel whey protein (CWP) on sepsis-associated acute lung injury caused by different bacteria in mice.

METHODS  After C57L/6 mice were adaptively fed for one week, 40 mice were randomly divided into five groups, with eight mice in each group: sham operation group (Sham group), gram-positive/negative sepsis group (G⁺/G⁻sepsis group) and gram-positive/negative sepsis + CWP intervention group (G⁺/G⁻sepsis + CWP group). Mice in the G⁺/G⁻sepsis + CWP group were pretreated with a synchronous gavage of 200 mg/kg CWP freeze-dried powder solution once a day for seven consecutive days. Mice in the Sham group and G⁺/G⁻sepsis group were given an equal volume of saline for synchronous gavage. After 24 hours of the last intervention, except for the Sham group, the remaining groups were chosen to establish models of sepsis-related acute lung injury caused by G⁺/G⁻bacterial infection. Taking the modeling time of each group as the starting point, sample collection and indicator detection were performed on the 1st, 3rd and 7th day, respectively. After modeling, the general conditions were observed and recorded. The pathomorphological changes in lung tissue were observed by HE staining. The lung edema degree was evaluated by the wet/dry weight ratio (W/D) of lung tissue. The levels of inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1β and IL-10 in the bronchoalveolar lavage fluid (BALF) were detected. The apoptosis of lung tissue cells was observed by TUNEL staining. The expression levels of apoptosis-related proteins in the lung tissue were detected by Western Blotting.

RESULTS  Compared with the Sham group, on the 1st, 3rd and 7th day after modeling, the pathological injury scores and W/D of lung tissues in the G⁺/G⁻sepsis groups increased, the levels of pro-inflammatory cytokines TNF-α, IL-6 and IL-1β in BALF increased, the level of anti-inflammatory cytokine IL-10 decreased, the number of apoptotic cells in lung tissue increased, the expression of Bcl-2 protein decreased, and the expression of Cleaved-Caspase-3 and Caspase-3 proteins increased (P＜0.05). On day 1, day 3 and day 7 after CWP intervention, the general conditions of mice in the G⁺/G⁻sepsis + CWP group improved compared to those in the G⁺/G⁻sepsis group, with improved pathomorphology of lung tissue, reduced lung injury scores, decreased lung tissue W/D, increased level of anti-inflammatory cytokine IL-10 in BALF, decreased levels of pro-inflammatory cytokines TNF-α, IL-6 and IL-1β and number of apoptotic cells in lung tissue, increased expression of Bcl-2 protein and decreased expression of Cleaved-Caspase-3 and Caspase-3 proteins (P＜0.05), all showing time-dependent changes (P＜0.001).

CONCLUSION  CWP can alleviate pathological lung tissue damage, reduce lung tissue edema, and regulate the body's inflammatory response in mice with sepsis, and action mechanisms may be related to the regulation of pathways associated with apoptosis in lung tissue cells.