Objective To investigate the mechanismof lung injury caused by paraquat poisoning by observing the changes of fibrogenic cytokines in acute paraquat poisoned rats and the effects of pyrrolidine dithiocarbamate ( PDTC) . Methods Sprague-Dawley rats were randomly divided into three groups, ie. acontrol group ( n =6) , a PDTC group ( n =36) , a paraquat group ( n = 36) , and a paraquat + PDTC group( n =36) . The rats in the PDTC group, the paraquat group, and the paraquat + PDTC group were subdivided into 6 subgroups sacrificed respectively on 1st, 3rd,7th,14th, 28th and 56th day after the treatment. The levels of transforming growth factor-β1( TGF-β1 ) , platelet-derived growth factor ( PDGF) , insulin-like growthfactor-1 ( IGF-1) in serum were measured. Meanwhile the expression of connective tissue growth factor ( CTGF) and hydroxyproline in lung tissues were detected. The relationship of above cytokines with hydroxyproline was analyzed. Results The destructive phase in early ( 1 ～7 d) was characterized by hemorrhage, alveolar edema, and inflammatory cell infiltration. The proliferous phase in later stage ( 14 ～56 d) was characterized by diffused alveolar collapse with fibroblast proliferation and patchy distribution of collagen fibers. Compared with the control group, the level of TGF-β1 on all time points, the level of PDGF from7th to 56th day, the level of IGF-1 from3rd to 56th day in the paraquat group all significantly increased ( P lt;0. 01) . Immunohistochemistry results showed CTGF positive cells mainly located in aleolar epithelialcells, endothelial cells,macrophages in early stage, and fibroblasts were main positive cells on the 28th and the 56th day. The expression of CTGF in the paraquat group increased gradually compared with the control group on different time points ( P lt; 0. 05 or P lt; 0. 01) . Meanwhile, the levels of above cytokines were positively correlated with the level of hydroxyproline. Noteworthy, PDTC treatment led to significant decreases of above cytokines compared with the paraquat group in corresponding time points ( P lt;0. 05 or P lt;0. 01) .Conclusions Over expressions of IGF-1, TGF-β1 , PDGF, IGF-1 and CTGF may play important roles in lung fibrosis of paraquat poisoned rats. PDTC, as a b NF-κB inhibitor, may inhibits NF-κB activity and further significantly decreases expressions of cytokines, leading to significantly attenuated pulmonary inflammation and fibrosis. However, the mechanisms of PDTC intervention still remain to be explored.
ObjectiveTo analyze the clinical and pathologic features of paraquat poisoning, discuss the damage mechanism of pulmonary fibrosis caused by paraquat poisoning. MethodsWe retrospectively analyzed the paraquat poisoning-related cases collected in recent years from January 2010 to December 2013, and compared the clinical features and pathologic changes between acute and chronic paraquat poisoning cases. ResultsThe main clinical and pathologic manifestation of paraquat poisoning was multiple organ damage, especially with lung as its target organ. In acute poisoning deaths, the lung injury was characterized by the pulmonary edema and formation of lung transparent membrane; In chronic poisoning deaths, the injury was characterized by the formation of lung transparent membrane and pulmonary fibrosis. ConclusionIn order to make an earlier diagnosis in clinical cases, we should strengthen the cognition of clinical manifestations and damage mechanism of paraquat poisoning. To obtain an accurate conclusion in forensic medicine appraisal, we should draw a comprehensive analysis of the forensic case, the clinical data, the toxicological analysis and the autopsical results.
ObjectiveTo investigate the endoplasmic reticulum stress associated apoptosis gene Caspase-12 expression in paraquat-induced pulmonary fibrosis. Methods30 adult healthy Sprague-Dawley(SD) rats were randomly divided into a nomal control group,two pulmonary fibrosis model groups (intragastrically administered paraquat for 14 days and 28 days,respectively).The model of pulmonary fibrosis was established through intragastrically administering paraquat at the dose of 30 mg/kg.RT-PCR was used to determine the mRNA expression of Caspase-12.Immunohistochemistry was used to determine the protein expression of Caspase-12.HE staining and Masson staining were used to determine the degree of alveolitis and pulmonary fibrosis. ResultsHE staining and Masson staining of lung tissues proved that pulmonary fibrosis model was successfully constructed.The degree of alveolitis and pulmonary fibrosis in the model group was significantly more serious than that in the control group(P<0.01).RT-PCR and Immunohistochemistry results showed that the expression of Caspase-12 were remarkably increased in the pulmonary fibrosis model group(14 d group)(P<0.01),even more elevated in 28 d group compared with the 14 d group. ConclusionThe results demonstrate that the expression of Caspase-12 in paraquat poisoned rats is up-regulated,suggesting endoplasmic reticulum stress plays an important role in paraquat induced-pulmonary fibrosis.
ObjectiveTo investigate the changes of inflammatory cytokines in bronchoalveolar lavage fluid (BALF) in rats exposed to paraquat (PQ). MethodsAdult healthy SD rats were randomly divided into a control group (n=8) and three experimental groups (PQ in low dosage of 15 mg/kg,medium dosage of 30 mg/kg,and high dosage of 60 mg/kg,n=24 in each group). The rats in three experimental groups were intragastrically administered with PQ,and the rats in the control group were treated with saline by gavage. Two rats in the control group and six rats in three experimental groups were sacrificed on 1st,7th,14th,and 21st day after exposure respectively. BALF was collected for measurement of interleukin-1(IL-1),IL-6,macrophage inflammatory protein-2(MIP-2),monocyte chemoattractant protein-1(MCP-1),and biopterin by ELISA. ResultsThe levels of cytokines in all experimental groups were higher than those in the control group at any time point. In the exposure day 1 to day 14, IL-1 and biopterin levels in BALF increased significantly with the increase in PQ dose. On 14th and 21st day,IL-6 level in BALF increased significantly with the increase in PQ dosage. The levels of IL-1,IL-6,and biopterin in the experimental groups reached the peak on 14th day. On 14th day,the MIP-2 level in BALF of high-dosage group was significantly higher than that of low-dosage and medium-dosage groups (all P<0.05). The level of MCP-1 in the low-dosage group was lower than that in the medium-dosage and high-dosage groups at any time point (P<0.05). ConclusionIL-1,IL-6,MIP-2,MCP-1,and biopterin may play important roles in the development and progression of PQ-induce lung inflammation.
ObjectiveTo explore the differential diagnosis value of subpleural bandlike ground-glass opacity (GGO) in thoracic CT in paraquat poisoning pneumonia. MethodsA retrospective study was carried out by retrieving the patients CT database from March 2013 to March 2015. The patients with paraquat poisoning pneumonia, interstitial pneumonia and pulmonary alveolar proteinosis (PAP) were recruited and their radiological characteristics of thoracic CT were analyzed. ResultsA total of 698 newly diagnosed interstitial pneumonia patients were finally enrolled in this study, 392 of them (56.2%) presented with GGO in thoracic CT. A total of 38 newly diagnosed PAP patients and 14 paraquat poisoning patients were enrolled, and GGO presented in thoracic CT of 100.0% and 42.9% of them respectively. Subpleural bandlike GGO was mostly commonly found in 83.3% of the paraquat poisoning pneumonia patients with GGO in thoracic CT, followed by 18.4% of the PAP patiens and 5.6% of the interstitial pneumonia patients with GGO in thoracic CT, which were significantly lower than that in the paraquat poisoning pneumonia patients (P < 05). GGO associated crazy paving pattern in thoracic CT was mostly commonly found in 94.7% of the PAP patients, followed by 0.5% of the interstitial pneumonia patients and none of the paraquat poisoning pneumonia patients. All the PAP patients with subpleural bandlike GGO were found associated with crazy paving pattern, while none of such association was found in the interstitial pneumonia or the paraquat poisoning pnuemonia patients. GGO coexisting with honeycombing and subpleural line were respectively found in 22.7% and 11.2% of the interstitial pneumonia patients, and none of such association was found in the PAP or the paraquat poisoning pneumonia patients. ConclusionsSubpleural bandlike GGO is mostly commonly found in paraquat poisoning pneumonia patients and rarely in PAP and interstitial pneumonia patients. Combined with crazy paving pattern and subpleural line, subpleural bandlike GGO may be a valuable feature in the diagnosis of paraquat poisoning pneumonia patients.
ObjectiveTo establish paraquat (PQ)-induced acute respiratory distress syndrome (ARDS) mice model via gavage, in order to simulate oral adminitration in clinical situations.MethodsSeventy-eight 6-8-week-old, specific pathogen free female C57 mice were chosen in this study. The mice were randomly divided into the control group (n=6) and the PQ model group(n=36); the mice in the latter group were randomly divided into 6 poisoning model subgroups further, with 6 mice in each, to find out the suitable concentration of PQ to establish stable ARDS model. The mice in the control group were given phosphatebuffer saline (PBS) by gavage, 200 μL per mouse; while the mice in the 6 poisoning model subgroups were given PQ with varies doses of 3, 10, 30, 100, 150, 300 mg/kg respectively by gavage. The clinical manifestations were observed for 7 days, and the ratio of lung wet/dry (W/D) was measured. After the suitable concentration of PQ for stable ARDS mice model was found, the other 36 mice were randomly divided into the controlgroup and the poisoning model group, both were divided into 4 subgroups, according to different observation point in time (1 day and 2, 3, 4 days after PQ gavage). The mice in the 4 control subgroups (n=3) were given PBS by gavage, 200 μL per mouse; while the mice in the 4 poisoning model subgroups (n=6) were given PQ with the suitable concentration for ARDS mice model by gavage. Pathological manifestations by Haematoxylin-Eosin staining and lung injury score were observed and analyzed.ResultsThe mice began to die at the PQ dosage of 150 mg/kg; while the death rate was stable at 300 mg/kg. On the 2nd and 4th day after PQ gavage, lung W/D was 5.335, 6.113, and 5.525, and 6.403, respectively in the mice in 150 and 300 mg/kg subgroup, which differed much from those in the control group (P<0.001). Congestion, edema, hemorrhage, alveolar structure damage, inflammation cells infiltration of lung tissue were observed, and lung injury score increased.ConclusionPQ-induced ARDS mice model by gavage is established successfully.