Dexmedetomidine preconditioning protects against lipopolysaccharides-induced injury in the human alveolar epithelial cells / Pré-condicionamento com dexmedetomidina protege contra lesões induzidas por lipopolissacarídeos em células epiteliais alveolares humanas

Abstract Background and objectives Dexmedetomidine (DEX) has demonstrated the preconditioning effect and shown protective effects against organize injury. In this study, using A549 (human alveolar epithelial cell) cell lines, we investigated whether DEX preconditioning protected against acute lung injury (ALI) in vitro. Methods A549 were randomly divided into four groups (n = 5): control group, DEX group, lipopolysaccharides (LPS) group, and D-LPS (DEX + LPS) group. Phosphate buffer saline (PBS) or DEX were administered. After 2 h preconditioning, the medium was refreshed and the cells were challenged with LPS for 24 h on the LPS and D-LPS group. Then the malondialdehyde (MDA), superoxide dismutase (SOD), Bcl-2, Bax, caspase-3 and the cytochrome c in the A549 were tested. The apoptosis was also evaluated in the cells. Results Compare with LPS group, DEX preconditioning reduced the apoptosis (26.43% ± 1.05% vs. 33.58% ± 1.16%, p < 0.05) in the A549, which is correlated with decreased MDA (12.84 ± 1.05 vs. 19.16 ± 1.89 nmoL.mg-1 protein, p < 0.05) and increased SOD activity (30.28 ± 2.38 vs. 20.86 ± 2.19 U.mg-1 protein, p < 0.05). DEX preconditioning also increased the Bcl-2 level (0.53 ± 0.03 vs. 0.32 ± 0.04, p < 0.05) and decreased the level of Bax (0.49 ± 0.04 vs. 0.65 ± 0.04, p < 0.05), caspase-3 (0.54 ± 0.04 vs. 0.76 ± 0.04, p < 0.05) and cytochrome c. Conclusion DEX preconditioning has a protective effect against ALI in vitro. The potential mechanisms involved are the inhibition of cell death and improvement of antioxidation.

Resumo Justificativa e objetivos Dexmedetomidina (DEX) demonstrou ter efeito pré-condicionante e também efeitos protetores contra lesão organizada. Neste estudo, com células A549 (células epiteliais alveolares humanas), investigamos se o pré-condicionamento com DEX proporcionaria proteção contra lesão pulmonar aguda (LPA) in vitro. Métodos Células A549 foram aleatoriamente distribuídas em quatro grupos (n = 5): controle, DEX, lipopolissacarídeos (LPS) e D-LPS (DEX + LPS). Administramos solução de PBS (tampão fosfato-alcalino) ou DEX. Após 2 h de pré-condicionamento, o meio foi renovado e as células desafiadas com LPS por 24 h nos grupos LPS e D-LPS. Em seguida, malondialdeído (MDA), superóxido dismutase (SOD), Bcl-2, Bax, caspase-3 e em A549 foram testados. Apoptose também foi avaliada nas células. Resultados Em comparação com o grupo LPS, o pré-condicionamento com DEX reduziu a apoptose (26,43% ± 1,05% vs. 33,58% ± 1,16%, p < 0,05) em células A549, o que está correlacionado com a diminuição de MDA (12,84 ± 1,05 vs. 19,16 ± 1,89 nmol.mg-1 de proteína, p < 0,05) e aumento da atividade de SOD (30,28 ± 2,38 vs. 20,86 ± 2,19 U.mg-1 de proteína, p < 0,05). O pré-condicionamento com DEX também aumentou o nível de Bcl-2 (0,53 ± 0,03 vs. 0,32 ± 0,04, p < 0,05) e diminuiu o nível de Bax (0,49 ± 0,04 vs. 0,65 ± 0,04, p < 0,05), caspase-3 (0,54 ± 0,04 vs. 0,76 ± 0,04, p < 0,05) e citocromo c. Conclusão O pré-condicionamento com DEX tem efeito protetor contra LPA in vitro. Os potenciais mecanismos envolvidos são inibição da morte celular e melhoria da antioxidação.

Effect of radix paeoniae rubra on expression of p38 MAPK/iNOS/HO-1 in rats with lipopolysaccharide-induced acute lung injury / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the effect of radix paeoniae rubra (RPR) on expression of p38 mitogen activated protein kinase (MAPK)/iNOS/HO-1 in rats with lipopolysaccharide-induced acute lung injury and explore the molecular mechanism.</p><p><b>METHODS</b>Forty healthy male Wistar rats, weighing 200-250 g, aged 6-8 weeks (mean equal to 7 weeks), provided by the Experimental Center, Medical College, Wuhan University, Wuhan, China, were employed in this study. Under anesthesia with 7% chloraldurat (5 ml/kg body weight) through intraperitoneal injection, the trachea of the rat was exposed and an arterial puncture needle pricked into the trachea via cricothyroid membrane. Then they were randomly divided into five groups: 8 rats receiving 1 ml normal saline through the puncture needle (Group A), 8 receiving 1 ml lipopolysaccharide (LPS, 2.5 mg/kg, Group B), 8 receiving LPS and RPR (30 mg/kg, pumped through the femoral vein for 2 hours, Group C), 8 receiving RPR 2 hours before dripping LPS (Group D), and 8 receiving hemin (75 micromol/L through intraperitoneal injection) 18 hours before dripping LPS (Group E). After 6 hours of LPS dripping, blood samples were obtained through the carotid artery to perform blood gas analysis, then all the rats were exsanguinated to death and specimens of lung tissues were obtained. The pathomorphological changes of the lung tissues were observed. The expression of p38 MAPK/iNOS/HO-1, the neutrophil ratio, protein content in alveolar irrigating solution and malonaldehyde (MDA) content in the lung tissues were also detected.</p><p><b>RESULTS</b>Compared with Group A, the expression of p38 MAPK, iNOS and HO-1 markedly increased in Groups B, C, D, and E (P < 0.01). But in Groups C, D and E the expression of p38 MAPK and iNOS were significantly lower than that of Group B, while expression of HO-1 was obviously higher than that of Group B (P < 0.05). The protein content, the ratio of neutrophils in bronchoalveolar lavage fluid (BALF), the content of MDA and the activities of serum NO in Group B were significantly higher than those of Group A (P < 0.01). There was a significant decrease in the level of arterial bicarbonate and partial pressure of oxygen in Group B (P < 0.01). Compared with Group B, these indexes of lung injury were significantly lower while the levels of arterial bicarbonate and partial pressure of oxygen increased significantly in Groups C, D and E (P < 0.05 or P < 0.01). Under light microscope, the pathological changes induced by LPS were significantly attenuated by RPR and hemin.</p><p><b>CONCLUSIONS</b>The high expression of MAPK plays an important role in lipopolysaccharide-induced acute lung injury. Protective effect of RPR on lipopolysaccharide-induced acute lung injury may be related to the inhibition of the abnormal high expression of p38 MAPK/iNOS/HO-1.</p>