Protective effect of anti-inflammatory peptides on LPS-induced acute lung injury of mouse

Abstract

Objective To explore the anti-inflammatory effect of antiflammin-2 (AF2) and recombinant peptide sequence 2(R2) on acute lung injury of mouse. To observe the expression of clara cell 16000 protein (CC16) and surfactant protein A (SP-A) in the lung of mouse inoculated with lipopolysaccharide (LPS) and the impact of AF2,R2,and glucocorticoids(hydrocortisone,HC) may have on the expression of the CC16 and SP-A in the lung of mice with acute lung injury. Methods Balb/c mice were inoculated with LPS (5 mg/kg) by intraperitoneal injection to set up ALI mice model. Mice weighed from 15 g to 16 g were grouped into control group, model group and treated groups respectively treated with AF2, R2 or HC. Mice in the control group were injected with physiological saline solution, while mice in the other four groups were inoculated with LPS to induce acute lung injury. Then animals in the treated groups were treated with AF2, R2 or HC each on a dose of 2 mg/kg also through intraperitoneal injection,while those of the control group and the model group, were given equivalent physiological saline solution as a placebo. The respiratory rate of all of these animals were recorded 6 hours after the injection. And at the time point of 12 hour,all the mice were sacrificed for a preparation of the whole lung tissue for the sake of a pathological investigation ,or for extractions of RNA for a semiquantitative analysis of the expression of CC16 and SP-A within the lungs. Results (1) An obvious attenuation of the respiratory rates of the three treated groups were observed when comparing with that of the mice in the model group without any anti-inflammatory treatment. (2) Remarkable extenuation of the extent of intra-alveolar and intersticial hemorrhage and infiltration of inflammatory cells were observed within the treated groups comparing with that of the model group. (3) An attenuate expressions of CC16 or SP-A were observed in the model group,while obvious uptrend of CC16 expression was observed in AF2 treated groups and increase of SP-A expressions were found in R2 and HC treated groups. Conclusion The anti-inflammatory effect of the peptide, AF-2 or R2, has been conformed on ALI mice model induced by LPS. Key words: Antiflammin-2; Clara cell 16 000 protein; Surfactant protein A; Lipopolysaccharide; Acute lung injury; Mice