Effects of epinephrine on early inflammatory cytokines and acute lung injury in endotoxemic rats

Abstract

Objective To investigate the effects of epinephrine in sepsis-associated lung injury in rats. Methods Thirty SD rats were randomly divided into three groups(n=10 per group): control group received intravenous 0.9% saline 2.4 ml/(kg·h); LPS group received intravenous LPS(6 mg/kg); epinephrine treatment group received an infusion of epinephrine 0.6 μg/(kg·min) after LPS intravenous injection.Blood samples were taken at 2 h and 6 h after LPS injection and the levels of serum tumor necrosis factor(TNF)-α, interleukin(IL)-6 and IL-10 were detected.The rats were sacrificed at 6 h. The lung tissues and bronchoalveolar lavage fluid(BALF) were collected.Pathological changes of the lung tissues were observed under light microscope.Water content of lung, expression of TNF-α, IL-6 and IL-10 in BALF and in serum were detected. Results (1)The water content of lung in LPS group significantly increased compared with that in control group(85.24%±5.87% vs. 70.19%±5.87%)and epinephrine group(78.00%±6.41%)(P<0.05). (2)Pathological examination showed that LPS could cause pulmonary capillary hyperemia, edema, inflammatory cells infiltration.Atelectasis and alveolar edema were found in small number of lung tissue.Compared with LPS group, epinephrine ameliorated the lung pathological injury.(3)Compared with LPS group, serum levels of TNF-α and IL-6 significantly decreased(P<0.05), whereas IL-10 increased(P<0.05) in epinephrine group.(4)Compared with LPS group, BALF levels of TNF-α[(78±9)ng/L vs.(102±16) ng/L] and IL-6[(268±42)ng/L vs.(347±50) ng/L]significantly depressed(P<0.05), whereas BALF levels of IL-10[(210±23)ng/L vs.(146±34) ng/L]elevated(P<0.05) in epinephrine group. Conclusion Epinephrine could reduce the acute lung injury caused by LPS.Its protective effect may be related to decreasing the levels of TNF-α and IL-6, elevating IL-10 level. Key words: Epinephrine; Sepsis; Inflammatory mediators; Acute lung injury; Rats