Saikosaponin-d attenuates ventilator-induced lung injury in rats.

Saikosaponin-d is one of the main bioactive components in the traditional Chinese medicine Bupleurum falcatum L and possesses anti-inflammatory and immune-modulatory properties. The current study aimed to investigate the protective effects of saikosaponin-d on ventilator-induced lung injury (VILI) in rats. We found that saikosaponin-d treatment significantly attenuated the pathological changes of lungs induced by mechanical ventilation. Administration of saikosaponin-d reduced the pulmonary neutrophil infiltration as well as the MPO concentrations. Saikosaponin-d also decreased the expression of pro-inflammatory cytokines including MIP-2, IL-6 and TNF-α. Meanwhile, the expression of anti-inflammatory mediators, such as TGF-β1 and IL-10, was obviously elevated after saikosaponin-d administration. Saikosaponin-d remarkably reduced the oxidative stress and apoptosis rate in lung tissues. On the molecular level, saikosaponin-d treatment obviously downregulated the expression of caspases-3 and the pro-apoptotic protein bax, and promoted the expression level of anti-apoptotic protein bcl-2. Collectively, our study demonstrated that saikosaponin-d may attenuate ventilator induced lung injury through inhibition of inflammatory responses, oxidative stress and apoptosis.