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Objective: paraquat (paraquat, PQ), is currently the most widely used herbicide worldwide. In recent years, China's application PQ is the increasing number of reports of poisoning showed a rising trend. Although PQ herbicidal very effective, but it is highly toxic for humans and animals. And its pathogenesis has not been fully elucidated, few effective treatment measures, more specific antidote. Clinical observation have seen, the larger dose poisoning patients often rapidly fatal due to multiple organ failure of the heart, liver, kidney, lung, and poisoning survival of smaller doses often cause delayed pulmonary fibrosis, a relatively long duration . Access to domestic and international literature, No more comprehensive experiment to explore the relationship between the different doses of PQ poisoning and organ injury, for which we designed from the pathological changes, enzymatic indicators, blood biochemical tests of PQ poisoning caused important organ damage characteristics compared to the systematic study of the test, in order to seek the effective treatment of highly targeted drugs. Methods: In this study, mainly through the establishment of an animal model study. First with sterile saline to 20% of the PQ solution configured as a concentration of a solution of 5mg/ml. 112 selected adult male mice, body weight 25 ± 5g, were randomly divided into four groups (n = 28): ① normal control group (intraperitoneal injection of saline 75mg/kg) ② paraquat injection of small dose group (intraperitoneal injection of paraquat 50mg/kg), ③ paraquat injection in dose group (intraperitoneal injection of the paraquat 75mg/kg), ④ paraquat injection in the high-dose group (intraperitoneal injection of paraquat 100mg/kg). Animals in each group respectively poisoning after 6h, 1d, 3d, 7d, 14d, 28d batches blood tests, including liver function (ALT, AST). Renal function (BUN, Cr), and then the animals were sacrificed, and each time of each group were killed 4. Anatomy, animals were sacrificed the clipping right lung and liver tissue frozen in liquid nitrogen, and stored at -85 ℃ to take advantage of the the kit detects tissue homogenates superoxide dismutase (SOD) activity and malondialdehyde (MDA Select the liver, kidney, left lung, conventional HE staining) content; Histopathological observation all test results are respectively; small dose exposure group lungs in addition to routine HE staining, and two associated staining of collagen and elastic fibers; compared with the control group, and the diversity of this mean variance analysis. Results: 1. Small dose group after exposure to loss of appetite, weight slightly mitigate, shortness of breath, such as performance, but about 7d resumed. Medium and large dose group mice exposed to the damage of the the obvious respiratory system, nervous system, digestive system, etc., and the weight loss, the mice in the death of 3-7d more. 2. Histopathological observation, small dose group mice liver and kidney tissue damage slightly higher than those in the high-dose exposure group, exposed to high dose group early that a large number of liver necrosis and tubular protein casts; lung tissue in small dose group mainly for the cause of late pulmonary fibrosis, and high-dose exposure group early you can see multi edema, and mice died of multiple organ failure in the early stage of pulmonary hemorrhage. 3. SOD activity and MDA content in liver homogenates small dose exposure group had no significant change (P> 0.05), and high-dose exposure group most of the time, the changes were significant (P <0.05 or P <0.01). Monitoring two indicators in the lung tissue homogenates at each time point compared with the control group change significantly (P <0.05 or P <0.01), and the same point in time, the greater the exposure dose, the more obvious changes. 4. Exposed to small doses of serum ALT, AST, BUN, Cr value late increase was more pronounced (P <0.05), and early addition to BUN increased (P <0.05) in the 3d and the rest of the point in time there was no significant change (P> 0.05). The middle dose group in addition to 6h. Transaminase no significantly higher (P> 0.05), the rest of the time point of the indicators increased significantly (P <0.05 or P <0.01). Exposed to high-dose group at each time point serum ALT, AST, BUN, Cr were significantly higher (P <0.05 or P <0.01). Conclusion: According to the experimental results can be considered: 1. Mild renal pathological damage, mainly associated with cell cycle disorders slight swelling liver, small dose group, showed a small arteriovenous and capillary congestion, slow blood flow and liver double mononucleosis, renal tubular epithelial swelling. Lung tissue unless there is congestion, the major changes are caused by pulmonary fibrosis, mainly in the latter part of the lung fibrous tissue hyperplasia, local fibrosis tendencies. Medium and large dose group mice early stage hydropic degeneration of the liver cells, spotty necrosis, pulmonary hemorrhage, edema, and tubular seen more protein, epithelial casts. 2. Small dose exposure group increased SOD activity decreased and MDA content in liver homogenates are not obvious, that peroxide damage lighter, lower SOD activity and MDA content in the lung tissue increased lipid peroxidation damage. Medium and large dose group liver and lung tissue SOD activity decreased and MDA content increased significantly changed, the serious injury of lipid peroxidation. 3. Exposed to small doses of serum ALT and AST values ??pre no significant change late elevated BUN value in the third day after exposure significantly increased, Cr was increased when the 28d, indicating that the dye in small doses The Poison groups associated with lung tissue dysfunction, decreased oxygen saturation, the late liver lesions obvious; kidney as paraquat major metabolic organ, there is still some damage in the case of small-dose exposure. Medium and large dose group serum ALT, AST, BUN, Cr significantly increased liver, kidney tissue suffered serious damage.
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