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>

Protective effect of melatonin in rats with phosgene-induced lung injury / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the antioxidant effect of melatonin (MT) in the rats with phosgene-induced lung injury and its possible mechanism.</p><p><b>METHODS</b>Fifty male SD rats were equally randomized into phosgene exposure group, air control group, MT treatment group, dexamethasone (DX) treatment group, and negative control group. All groups except the air control group were exposed to 8.33 mg/L phosgene for 5 min, and the MT treatment group, DX treatment group, and negative control group were injected with MT (10 mg/kg), DX (2.5 mg/kg), and 1% ethanol saline (1 ml/kg), respectively, via the caudal vein 1 hour after exposure. The rats were sacrificed 6h later. Then, the wet/dry ratio of the lung, the total protein content and neutrophil count in bronchoalveolar lavage fluid (BALF), and the malonaldehyde (MDA) content and superoxide dismutase (SOD) and myeloperoxidase (MPO) activities in lung homogenate were measured; pathological observation was made on the lung tissue under an optical microscope; the protein expression of inducible nitric oxide synthase (iNOS) and NF-κB in the lung tissue was measured by Western blot.</p><p><b>RESULTS</b>Compared with the air control group, the phosgene exposure group showed significantly increased wet/dry ratio of the lung and total protein content and neutrophil count in BALF (P < 0.01) as well as significantly increased MDA content and MPO activity in the lung tissue (P < 0.05). Compared with the phosgene exposure group, the MT treatment group showed significantly decreased MDA content and MPO activity and significantly increased SOD activity (P < 0.01), and the MT treatment group and DX treatment group showed significantly decreased protein expression of iNOS and NF-κB (P < 0.01).</p><p><b>CONCLUSION</b>MT has protective effect in phosgene-induced lung injury, and its protective mechanism may be associated with scavenging free radicals and inhibiting expression of iNOS and NF-κB.</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>

Effects of dexamethasone pretreatment on expression of matrix metalloproteinase-9 in rats with acute lung injury induced by phosgene / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of dexamethasone on expression of matrix metalloproteinase-9 (MMP-9) in rats with acute lung injury induced by phosgene.</p><p><b>METHODS</b>The rats were randomly divided into 3 groups: normal control group that consists of the rats with air exposure, phosgene group that consists of the rats with phosgene exposure and dexamethasone group that consists of the rats with phosgene exposure after 2.5 mg/kg dexamethasone being injected. Wet and dry ratio of the lung (W/D) was calculated, and leukocyte count and total protein content of bronchoalveolar lavage fluid (BALF) were recorded at 2 h after exposure. The concentrations of MMP-9 in the serum and BALF were measured by enzyme-linked immunosorbent assay. The pathologic changes of lung tissues were observed under light microscopy. The immunohistochemistry and the RT-PCR were used to detect the contents of MMP-9 in the lung tissue.</p><p><b>RESULTS</b>Compared with phosgene group, the lung W/D, protein content and WBC count in of BALF dexamethasone group was significantly decreased (P < 0.01). MMP-9 levels of the serum and BALF in dexamethasone group were (4.799 +/- 0.043) microg/L and (15.052 +/- 0.029) microg/L, respectively, which were significantly lower than those [(9.439 +/- 0.100) and (20.640 +/- 0.446) microg/L] in phosgene group (P < 0.01). Compared with phosgene group (2.789 +/- 0.282),the expression level (1.183 +/- 0.260) of lung MMP-9 mRNA in dexamethasone group was significantly lower than that in phosgene group (P < 0.01). Histological experimental results showed the marked hyperemia and thickening of alveolar walls and stroma cells infiltrating and more visible alveolar structure damage of alveolar walls in phosgene group while the alveolar structure and the alveolar walls were clear and slightly thickened with inflammatory cells in dexamethasone group. Immunohistochemical results showed that MMP-9 protein expression levels of lung and bronchus tissues in normal control group and dexamethasone group were weakly positive, which in phosgene group were strongly positive.</p><p><b>CONCLUSION</b>Dexamethasone has a beneficial effects on acute lung injury induced by phosgene in rats due to the inhibiting MMP-9.</p>

Protective effects of ulinastatin on phosgene-induced acute lung injury and relation to matrix metalloproteinase-9 / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To observe the protective mechanism of ulinastatin on mice with acute lung injury induced by exposure to phosgene and its relationship to the expressions of matrix metalloproteinase-9 (MMP-9) in the lung tissues.</p><p><b>METHODS</b>Sixty-four healthy male SD rats were randomly divided into two groups: the experimental group and the control group. 32 rats in the experiment group were randomly subdivided into four groups: rats with phosgene exposure group, rats with phosgene exposure after saline injected group, rats with phosgene exposure after dexamethasone injected group. 32 rats in the control group were randomly subdivided into four groups: rats with air exposure group, pretreated with ulinastatin before air exposure group, pretreated with saline before air exposure group, pretreated with dexamethasone before air exposure group, 8 animals in each group. After pretreated with the same dose of ulinastatin, saline, dexamethasone respectively, 32 rats in the control groups were exposed to the air on the same condition respectively for 5 min. While after pretreated with the same dose of ulinastatin, saline, dexamethasone respectively, 32 rats in the experiment groups were exposed to the phosgene which the concentration was 8.33 mg/L and with 100% purity for 5 min. The lung wet/dry (W/D) weight ratio was calculated, and total protein content and BALF leukocyte count were detected. The immunohistochemistry was used to detect lung tissue protein expression MMP-9 while enzyme-linked immunosorbent method was employed to detect MMP-9 in serum levels and enzyme original gelatinases spectrum method to detect BALF MMP-9 enzyme original content.</p><p><b>RESULTS</b>Compared with A1, A2, A3, A4 group, the lung W/D, BALF of protein content and WBC count in B1 and B2 group rats were significantly increased, and the difference was statistically significant (P < 0.01). There was statistically significant difference in lung W/D, BALF of protein content and white blood cell count between B1,B2 group and the B3 and B4 rats (P < 0.01). Histological experimental results showed marked hyperemia of alveolar walls, thickening in the lungs, alveolar walls and stroma cells infiltrating and more visible alveolar structure damage in B1 and B2 rats while the alveolar structure, the alveolar walls were clear and slightly thickened with inflammatory cells in B3 and B4 rats. Immunohistochemical result showed that the individual rats, lung and bronchus organization MMP-9 protein were weakly positive, B1 and B2 group MMP-9 protein expression was strongly positive,B3 group and the group MMP B4 lung tissue protein expression-9 weakens, restored to the normal lung tissue of weakly positive expression level. ELISA and gelatinases spectrum testing showed B1 and B2 rats, serum MMP-9 enzyme activity and content increased compared with A1, A2, A3, A4 group, the differences were statistically significant (P < 0.01), and B1, B2 group compared with the B3 and serum B4 group MMP-9 enzyme activity and the differences were obviously decreased, with statistically significant difference (P < 0.01).</p><p><b>CONCLUSIONS</b>Ulinastatin has protective effect on phosgene-induced ALL Ulinastatin can inhibit the up-regulation of expression of MMP-9.</p>