Effects of phosphorylated mitogen-activated protein kinases on phosgene inhalation-induced lung injury in rats and its relationship with matrix metalloproteinase / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the effects of phosphorylated mitogen-activated protein kinases (MAPK), including the phosphorylated extracellular signal-regulated protein kinase 1/2 (p-ERK1/2), the phosphorylated protein p38 (p-p38), the phosphorylated c-Jun N-terminal kinase (p-JNK), on phosgene inhalation-induced lung injury and its relationship with matrix metalloproteinase 9 (MMP-9).</p><p><b>METHODS</b>According to the random number table, 30 male Wistar rats were divided into air control group (C), phosgene inhalation group (P), PD98059 (specific inhibitor of ERK1/2) group, SB203580 (specific inhibitor of p38) group, and SP600125 (specific inhibitor of JNK) group, with 6 rats in each group. The number of neutrophils in the bronchoalveolar lavage fluid (BALF) was counted and the lung wet-dry ratio (W/D) was examined. The serum levels of inflammatory factors TNF-α, IL-1β, IL-6, and IL-8 were determined with ELISA. The protein expressions of p-ERK1/2, p-p38, p-JNK, and MMP-9 in lung tissue were detected with Western blotting. The mRNA level of MMP-9 in lung tissue was detected with real-time fluorescence quantitative PCR. Data were processed with one-way analysis of variance (among groups) and SNK method (paired comparison).</p><p><b>RESULTS</b>Compared with those of group C [respectively (2.0 ± 0.7)×10(4) /mL and 3.7 ± 0.6], the number of neutrophils and W/D of group P [respectively (10.7 ± 1.4)×10(4) /mL and 7.6 ± 0.4] were increased. The number of neutrophils in group SB203580 and group SP600125 was respectively (8.3 ± 1.1)×10(4), (7.9 ± 1.3)×10(4)/mL, with W/D respectively 6.1 ± 1.4, 6.1 ± 0.9, all of which decreased as compared with those of group P (with P values all below 0.01). Compared with those of group C, the levels of TNF-a, IL-1β, IL-6, and IL-8 of group P were increased, but decreased in group SB203580 and group SP600125 compared with that of group P, though still higher than those of group C, and the differences were statistically significant (P < 0.05 or P<0.01). Protein quantities of p-p38 and p-JNK were higher in group P (respectively 1.19 ± 0.22 and 1.43 ± 0.14) than in group C (respectively 0.76 ± 0.06 and 0.74 ± 0.05). Compared with those of group P, the protein levels of p-ERK1/2 (0.47 ± 0.05) in group PD98059, p-p38 (0.88 ± 0.07) in group SB203580, and p-JNK (0.91 ± 0.07) in group SP600125 were significantly reduced (P < 0.05 or P < 0.01). The protein and mRNA levels of MMP-9 were higher in group P (respectively 2.23 ± 0.18 and 4.93 ± 0.12) than in group C (respectively 1.26 ± 0.14 and 1.80 ± 0.03). The protein and mRNA levels of MMP-9 in group SB203580 (respectively 1.58 ± 0.14 and 2.96 ± 0.09) and group SP600125 (respectively 1.55 ± 0.30 and 3.00 ± 0.13) were lower than those in group P (P < 0.05 or P < 0.01).</p><p><b>CONCLUSIONS</b>The phosgene inhalation can activate the MAPK signaling protein pathway by increasing expressions of p-p38 and p-JNK, which lead to an up-regulation of MMP-9, and this may contribute to the phosgene inhalation-induced lung injury.</p>

Expression and role of mitogen activated protein kinases signaling pathway in lung injury induced by phosgene / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>This study aimed to investigate the expression and role of the mitogen activated protein kinases (ERK1/2, P38, JNK) in phosgene induced lung injury in rats in vivo.</p><p><b>METHOD</b>30 male wistar rats were randomized into the group as follows, Gas inhalation control group, Phosgene inhalation group, and the following groups of the inhibitors of MAPK, involving SP600125, PD98059 and SB203580, 6 animals in each group, we copy the model of phosgene-induced lung injury, used the directional flow-inhalation device, the air control group inhaled the air, and the intervention groups were given PD98059 (intraperitoneal injection), SB203580 (hypodermic injection), SP600125 (intravenous) respectively before the inhalation of phosgene. The locations and quantities of three subfamilies of MAPKs (ERK1/2, P38, JNK) and p-MAPKs (p-ERK1/2, p-P38, p-JNK) were analyzed by immunohistochemistry and Western Blot analysis respectively; The histopathological changes of lung tissues, the number of neutrophil cells and the W/D were examined.</p><p><b>RESULT</b>There were rare p-ERK1/2, p-P38 and p-JNK positive expression in alveolar and airway epithelial cells in control group. while the positive cells increased strikingly in phosgene inhalation groups, these cells involved in this process mainly included alveolar epithelial cells, air way epithelial cells, pleural mesothelial cells, infiltrative inflammatory cells, interstitium fibrocytes. After the intervention of the specific inhibitor, the positive cells decreased. As Western Blot analysis show, Protein quantities of p-P38 and p-JNK were higher in phosgene inhalation groups than those in control group, and the differences were significant (P < 0.05). Protein quantities of p-ERK1/2, p-P38 and p-JNK were lower in intervention groups than phosgene inhalation group, and the differences were significant (P < 0.05, P < 0.01). The lung injury in phosgene inhalation groups was more severer compared with the control group, the typical pathological characters of acute lung injury were discovered, the increase of the number of neutrophil cells and W/D. After the intervention of the specific inhibitor SP600125 and SB203580, the number of neutrophil cells and W/D reduced, and the differences were significant (P < 0.05, P < 0.01).</p><p><b>CONCLUSION</b>Phosgene inhalation may activate the MAPK signaling pathway, and the expression of the phosphorylation of MAPKs increased, especially the P38 ang JNK. The results may contribute to the lung injury induced by phosgene.</p>