RESUMEN
AIM: To investigate the role of hydrogen sulfide (H_2S) in the cholecystokinin octapeptide (CCK-8) attenuating lipopolysaccharide (LPS)-induced lung injury. METHODS: A rat model of lung injury induced by intravenous injection of LPS was developed. Male Wistar rats were divided into normal control group, LPS group, LPS+CCK-8 group and CCK-8 group. Six hours after LPS injection, partial pressure of oxygen in the arterial blood (PaO_2), H_2S content and cystathionine-γ-lyase (CSE) activity in lung tissue were detected. The mRNA expression of CSE in lung tissue was determined by RT-PCR;the structure of lung tissues was observed under optical microscope. RESULTS: Compared to normal control rats, the LPS-treated rats had significantly decreased PaO_2 level, increased index of quantitative assessment (IQA) score, while H_2S content, CSE activity and the mRNA expression of CSE in lung tissue were significantly increased (all P<0.05). Administration of CCK-8 into LPS-treated rats increased the PaO_2 level and alleviated the degree of lung injury (measured by IQA score). In addition, CCK-8 decreased H_2S content, CSE activity, and the mRNA expression of CSE (all P<0.05). No significant difference of the above-mentioned parameters between CCK-8 group and normal control group was observed. CONCLUSION: CCK-8 reduces LPS-induced lung injury through inhibiting the generation of endogenous H_2S.