Relationship between inflammatory responses and autophagy in lung tissues after scald and NOD2 signaling pathway in septic rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the relationship between inflammatory responses and autophagy in lung tissues after scald and nucleotide-binding oligomerization domain-containing protein 2 (NOD2) signaling pathway in septic rats.Methods Twenty SPF healthy male Sprague-Dawley rats,weighing 200-250 g,were divided into control group (group C,n=10) and sepsis after scald group (group SS,n=10) using a random number table.The rats were subjected to a third-degree scald burn covering 20％ of total body surface area (body surface was shaved and then exposed to 99-100 ℃ water for 12 s),and 24 h later muramyldipeptide 5 mg/kg was intravenously injected to induce sepsis.The rats were only exposed to 20 ℃ water,and 24 h later normal saline 1 ml was given instead in group C.At 6 h after muramyldipeptide injection in group SS and at 6 h after normal saline injection in group C,arterial blood samples were collected for determination of serum tumor necrosis factor-r and interleukin-6 concentrations by enzyme-linked immunosorbent assay.Then rats were sacrificed and lungs were removed tor measurement of activity of myeloperoxidase,NOD2 mRNA expression (using real-time polymerase chain reaction) and expression of receptor interacting protein 2,nuclear factor kappa Bp65 and microtubule-associated protein 1 light chain 3 Ⅰ (LC3 Ⅰ) and LC3 Ⅱ in lung tissues (by Western blot).The LC3 Ⅱ / Ⅰ ratio was calculated.Results Compared with group C,the expression of NOD2 mRNA,receptor interacting protein 2 and nuclear factor kappa Bp65 was significantly up-regulated,and the LC3 Ⅱ / Ⅰ ratio and serum tumor necrosis factor-α and interleukin-6 concentrations were increased in group SS (P＜0.05).Conclusion The mechanism underlying enhanced inflammatory responses and autophagy in lung tissues during sepsis after scald may be related to activation of NOD2 signaling pathway in rats.