Objective To investigate the effect of selective phosphatase inhibitors Salubrinal on autophagy and apoptosis in the lung tissue of rats with acute paraquat (PQ) poisoning,and to explore its mechanism.Methods 200 Wistar rats were randomly divided into four groups by randomized arrangement table formed by computer,with 50 rats in each group.PQ poisoning model was reproduced by one time gastric lavage with 1 mL of 40 mg/kg PQ solution followed by intraperitoneal injection of 1 mL normal saline (NS) once a day.The rats in control group were lavaged once with 1 mL of NS followed by intraperitoneal injection of 1 mL NS twice a day.The rats in Sal 0.5 and Sal 1.0 groups were intraperitoneal injected with 1 mL Salubrinal 0.5 mg/kg or 1.0 mg/kg on the 1st,3rd,and 5th day after PQ poisoning once a day.The lung tissue was harvested on the 7th day after poisoning,and the changes in histomorphology were observed using hematoxylin and eosin (HE) staining.The positive expression of autophagy-related protein LC3-Ⅱ in lung tissue was observed after immunohistochemistry staining,and LC3-Ⅱ and caspase-3 protein expressions were determined by Western Blot.Results HE staining results showed partial abnormal pulmonary structure in the PQ poisoning group:collapse of pulmonary alveoli,enlargement of the cavity,local infiltration of inflammatory cells,increasing thickness in the alveoli wall and obvious bleeding in the local lung tissue.Compared with the PQ poisoning group,the above changes in Sal 0.5 and Sal 1.0 groups were obviously relieved.It was shown by immunohistochemistry staining that compared with control group,the positive expression of LC3-Ⅱ was obviously decreased in the PQ poisoning group,Sal 0.5,and Sal 1.0 groups (A value:78.34 ± 10.71,76.52 ± 8.21,77.48 ± 9.11 vs.117.58 ± 15.26,all P＜0.05).There was no significant difference in positive expression of LC3-Ⅱ between each of the later three groups (all P＞0.05).Western Blot results showed:compared with the control group,the protein expressions of LC3-Ⅱ and caspase-3 were significantly increased in PQ poisoning group [LC3-Ⅱ (A value):0.22 ±0.05 vs.0.14 ±0.03,caspase-3 (A value):0.115 ± 0.013 vs.0.023 ± 0.006,both P＜0.05].Compared with PQ poisoning group,the protein expressions of LC3-Ⅱ and caspase-3 were obviously decreased in the Sal 0.5 and Sal 1.0 groups [LC3-Ⅱ (A value):0.19 ±0.05,0.18 ±0.04 vs.0.22 ±0.05; caspase-3 (A value):0.078 ±0.012,0.076 ±0.010 vs.0.115 ±0.013,all P＜0.05].Conclusions The endoplasmic reticulum stress-autophagy is activated in the pulmonary cell of acute PQ poisoning rats.Salubrinal can decrease the autophagy and apoptosis in the lung of rats with acute PQ poisoning,which play a role in the treatment.

Objective To investigate the effects of ulinastatin on autophagy and apoptosis of lung cells in rats with acute paraquat poisoning.Methods A total of 150 Wistar rats were randomly (random number) divided into three groups.The rats in control group had stomach lavaged once with 1 mL of normal saline followed by intraperitoneal injection of 1 mL normal saline twice a day.PQ poisoning model was produced by stomach lavaged once with 1 mL of 40 mg/kg PQ solution followed by intraperitoneal injection of 1 mL normal saline once a day.In PQ + ulinastatin (PU) group,UTI in dose of 12 000 U/kg was intraperitoneally injected in rats twice a day.The lung tissue was obtained on the 7th day after modeling,and the histopathological changes were observed under microscope after hematoxylin and eosin (HE) staining.The positive expressions of autophagy-related LC3 protein LC3 and Bcl-2 pretein in lung tissue were observed after immunohistochemistry staining,and the levels of LC3、Bax 、Bcl-2 proteins were determined by Western blot.Results HE staining Results showed:it was observed from the PQ poisoning group that the abnormal cellular structure,enlargement in the pulmonary alveoli,leaking a lot of inflammatory cells,increased thickness of the alveoli wall and bleeding in the local area of lung tissue.Compared with the PQ poisoning group,the above changes in ulinastatin groups were relieved.Western blot Results showed:compared with the control group,the protein expressions of LC3-A/B were significantly increased in PQ poisoning group [LC3-A/B expression (A scale):0.22 ± 0.05 vs.0.14 ± 0.03,F =22.48,P ＜ 0.01].compared with PQ group,the expression of LC3 A/B obviously increased in the group of PU [LC3-A/B expression (A scale):0.36 ± 0.08 vs.0.22 ± 0.05,F =22.78,P ＜ 0.01].compared with Con group,the expression of Bcl-2/Bax obviously decreased in the group of PQ [Bcl-2/Bax expression (A scale),0.11 ±0.04 vs.0.83 ± 0.09,F =154.43,P ＜ 0.01].Compared with PQ poisoning group,the protein expressions of Bcl-2/Bax were obviously increased in PU groups [Bcl-2/Bax expression (A scale):(0.63 ± 018) vs.(0.11 ±0.04),F =154.43,P ＜0.01].Immunohistochemistry result:compared with Con group,the expression of LC3 and Bcl-2 obviously decreased in the group of PQ [LC3expression (A scale):(78.34±10.71) vs.(117.58±15.26),F=31.63,P＜0.01) (Bcl-2 expression (A scale):(62.54±9.74)vs.(130.52 ± 9.86,F =118.44,P ＜ 0.01).Compared with PQ poisoning group,the protein expressions of LC3 and Bcl-2 were obviously increased in PU groups [LC3expression (A scale):(162.58 ± 25.76) vs.(78.34 ± 10.71),F=31.63,P＜0.01]; [Bcl-2 expression (A scale):(145.56±10.26) vs.(62.54±9.74),F=118.44,P ＜ 0.01].Conclusions Theendoplasmic reticulum stress-autophagy is activated in the lung cells of rats with acute PQ poisoning.UTI can adjust endoplasmic reticul um stress,increased the expression of Bcl-2 and enhance the proportion of Bcl-2/Bax to protect the lungs of rats from acute PQ poisoning.