| Part 1: Mechanism of Nrf2 / HO-1 signaling pathway in paraquat poisoning-induced lung injury in ratsObjective: To observe the expression and significance of Nrf2 / HO-1signaling pathway in paraquat poisoned rats.Method: 48 healthy female SPF SD rats were divided into 2 groups according to the random number table method,namely the control group(NS group)and the poisoning group(PQ group),each group was treated as 1d,3d,7d,each time point 8 Rats.The animal model of lung injury was prepared by intraperitoneal injection of paraquat(20mg / kg),and the control group was replaced with equal amount of normal saline.At each time point,rats were quickly killed and materials(blood and lung tissue)were taken.Hematoxylin-eosin staining(HE)was used to observe rat lung tissue;lung tissue was used to detect W / D ratio to observe pulmonary edema and MDA content and SOD activity determination;serum was centrifuged to detect serum using enzyme-linked immunosorbent assay(ELISA)Concentration levels of SAA-1and TNF-α cytokines;RT-PCR and Western Blot were used to detect the expression of Nrf2,HO-1 m RNA and protein in lung tissue.Results: Successfully established a paraquat rat lung injury model.Compared with the control group,the inflammatory cell infiltration in the alveolar,widening of the lung interval,and destruction of the alveolar structure in the poisoned group of rats;the lung W / D ratio increased;the expression levels of SAA-1 and TNF-α in serum increased(P <0.05);the content of lung MDA increased,SOD activity decreased;the expression levels of Nrf2,HO-1m RNA and protein in lung tissue increased significantly at various time points,the difference was statistically significant(P <0.05).The lung injury model of paraquat rats was successfully replicated.Conclusion: It is confirmed that after lung injury caused by PQ poisoning occurs,in order to maintain the redox balance in rats,the Nrf2 / HO-1 signaling pathway is activated,suppresses the release of immune factors and inflammation,and plays a role in protecting lung injury.Part 2: The protective mechanism of recombinant human brain natriuretic peptide on paraquat-induced lung injury in ratsObjective: This study aimed to study the protective mechanism of recombinant human brain natriuretic peptide in the treatment of PQ-induced lung injury.Method: 90 healthy female SPF SD rats were divided into 3 groups according to random number table method,namely control group(NS group),poisoning group(PQ group)and intervention group(PQ + rh BNP group),30 rats in each group,PQ Rats in the group were intraperitoneally injected with a single dose of PQ(30mg / kg),and the control group was intraperitoneally injected with the same amount of normal saline.In the PQ + rh BNP group,a single dose of PQ(30mg / kg)was intraperitoneally injected with rh BNP 1 h(20ug / kg),observe and record the 7-day mortality rate;72 healthy female SPF SD rats were divided into 3 groups according to the random number table method,namely the control group(NS group),the poisoning group(PQ group)and In the intervention group(PQ + rh BNP group),each group was treated as 1d,3d,and 7d,with 8 rats at each time point.The animal model of lung injury was prepared by intraperitoneal injection of paraquat(20mg / kg).The intervention group was intraperitoneally injected with paraquat 1h and then the tail vein was injected with rh BNP.The control group was replaced with equal amount of normal saline.At each time point,rats were quickly killed and materials(blood and lung tissue)were taken.Hematoxylin-eosin staining(HE)was used to observe the lung tissue of rats;the lung tissue was detected by W / D ratio to observe the pulmonary edema and the content of MDA,SOD and GSH-Px were determined;after serum centrifugation,serum IL-1β was detected by(ELISA),TNF-α cytokine concentration levels;RT-PCR and Western Blot detection of lung tissue Nrf2,HO-1,TGF-β1,IL-10 m RNA expression levels and lung tissue Nrf2,HO-1,TGF-β1 Expression of α-SMA protein.Results: The lung injury model of paraquat rats was successfully established.1)No rats died on the first day in each group,and the deaths were concentrated on 2-6 days.In the PQ group,the death cases from day 1 were 0,8,4,4,1,0,0 in order,and the overall mortality rate was 56.67%;in the PQ +rh BNP group,the death cases were 0,2,3 from day 1,3,0,1,0,the overall mortality rate was 30.00%.2)Compared with the control group,the PQ group and PQ + rh BNP group had inflammatory cell infiltration in the alveoli,widening of the lung interval,and destruction of the alveolar structure,but the PQ + rh BNP group was milder than the poisoning group.3)Compared with the control group,the lung dry and wet weight ratio of the PQ group and the PQ + rh BNP group both increased,and both gradually increased with the PQ poisoning time;but the PQ + rh BNP group compared the lung dry and wet weight at each time point PQ group is low.4)Compared with the control group,ELISA found that the serum levels of IL-1β and TNF-α in the PQ group and PQ + rh BNP group increased,but after rh BNP treatment,the IL-1β in the serum of PQ + rh BNP group rats And TNF-αcontent is lower than the PQ group.5)Compared with the control group,the MDA content in the lung tissue of the PQ group and the PQ + rh BNP group increased,SOD activity and GSH-PX content decreased.After rh BNP treatment,the MDA content of the PQ + rh BNP group was lower than that of the PQ group and SOD.The activity and GSH-PX content were higher than the PQ group,the difference was statistically significant(P <0.05).6)RT-PCR showed that compared with the control group,the expression of Nrf2,HO-1,TGF-β1 and IL-10 m RNA in the lung tissue of the PQ group and PQ + rh BNP group were significantly increased,but they were significantly higher In contrast,after rh BNP treatment,the expression of Nrf2 and HO-1m RNA in PQ + rh BNP group was higher than that in PQ group,while the expression of TGF-β1 and IL-10 m RNA was lower than that in PQ group.7)Western-blot results showed that compared with the control group,the protein expression levels of Nrf2,HO-1,TGF-β1,and α-SMA in the lung tissues of rats in the PQ group and PQ + rh BNP group were significantly increased,but compared with the PQ group Compared,the expression of Nrf2 and HO-1protein in lung tissue of PQ + rh BNP group was significantly increased,while the protein expression of TGF-β1 and α-SMA was lower than that of PQ group.Conclusion: Recombinant human brain natriuretic peptide has protective effects on PQ-induced lung injury in rats.It is possible to improve oxidative stress and inflammatory lung injury caused by PQ poisoning through the Nrf2 /HO-1 signaling pathway. |
PDF Full Text Request