ABSTRACT
<p><b>OBJECTIVE</b>To study the effect of omega-3 polyunsaturated fatty acids (omega-3 PUFA) on inflammation in lung tissue of rats with severe scald and its mechanism.</p><p><b>METHODS</b>Seventy-two adult SD rats were divided into sham scald group (SS, n = 8), treatment group 1 (T1, n = 32), treatment group 2 (T2, n = 32) according to the random number table. Rats in T1 group and T2 group were inflicted with 30% TBSA full-thickness scald, and then they were respectively injected with 100 g/L omega-3 PUFA (1 mL/kg) and 200 g/L long-chain fatty acid (2 mL/kg) via tail vein within 5 minutes after burn. The above two fatty acids with equivalent calories were continuously injected for 10 days (once a day). On post burn day (PBD) 1, 4, 7, and 10, serum level of TNF-alpha and level of macrophage inflammatory protein 1alpha (MIP-lalpha) in lung homogenate of T1 and T2 groups were detected, the levels of NF-kappaBp65 and macrophage migration inhibitory factor (MIF) in lung tissue of T1 and T2 groups were observed with immunohistochemical staining (recorded as score). Above-mentioned parameters were also determined in SS group. Data were processed with t test.</p><p><b>RESULTS</b>The levels of 4 parameters in T1 and T2 groups on PBD 1, 4, 7, 10 were higher than those in SS group (with t values from 3.411 to 8.782, P values all below 0.01), and those in T1 group on PBD 4, 7, 10 were lower than those in T2 group (with t values from 2. 321 to 2.785, P values all below 0.05). The serum level of TNF-alpha and levels of MIP-1alpha, NF-kappaBp65, and MIF in lung tissue in SS group was respectively (0.96 +/- 0.32) ng/mL, (76 +/- 16) pg/mL, 0.24 +/- 0.03, 1.31 +/- 0.03, and those in T1 and T2 groups all peaked on PBD 7 [(2.43 +/- 0.32) ng/mL, (210 +/- 56) pg/mL, 4.23 +/- 2.15, 4.69 +/- 1.83; (3.15 +/- 0.54) ng/mL, (274 +/- 64) pg/mL, 5.15 +/- 2.31, 5.37 +/- 2.16].</p><p><b>CONCLUSIONS</b>Omega-3 PUFA can effectively reduce serum level of TNF-alpha and levels of MIP-1alpha, NF-kappaBp65, and MIF in lung tissue of rats with severe scald, showing that it has a protective effect against injury of lung tissue.</p>