| Bisphenol A（BPA）is a ubiquitous environmental pollutant with tremendous effects on human health,which was widely used in plastic containers,medical devices,tableware and other industries and daily life.The role of macrophages is closely related to the state of polarization.A large number of studies have found that BPA exposure can affect the process of macrophage polarization.Selenium（Se）is an indispensable trace element in animals,which plays a key role in physiological processes.Se deficiency is a worldwide problem,which can cause various of tissue and organ damage,such as inflammation and fibrosis.Fibrosis is a pathological process characterized by proliferation of fibroblasts,and accumulation of extracellular matrix,accompanying by inflammatory damage.Studies have confirmed that macrophage polarization is one of the important reasons of fibrosis.Due to the characteristics of geochemical environment and the rapid development of chemical industry,BPA exposure and Se deficiency often occur at the same time in the environment.In order to investigate the effect of BPA exposure on the role of macrophage polarization in pancreatic fibrosis of broilers,80 1-day-old broilers were randomly divided into 4 groups:control group,BPA exposure group（BPA group）,Selenium deficiency group（-Se group）and BPA+-Se deficiency group（BPA+-Se group）,with 20 broilers in each group.In vitro experiment,the cells divided into seven groups:control group,BPA exposure group（BPA group）,BPA exposure and NAC group（BPA+-Se group+NAC group）selenium deficiency group（-Se group）,selenium deficiency and NAC group（-Se+NACgroup）,BPA+-Se deficiency group（BPA+-Se group）and BPA+Se deficiency and NAC group（BPA+-Se+NAC group）.The pathological structure of broiler pancreas,antioxidant levels（CAT,T-AOC,ROS,H2O2 and MDA）,JAK2-STAT3/NF-κB signaling pathway related genes（JAK2,STAT3 and NF-κB）,macrophage polarization related genes（CD86,IL-1β,TNF-α,CD163 and IL-10）and fibrosis related genes（α-SMA,FN1,COLIA1,MMP2,TIMP2,TGF-β1 and Smad3）were analyzed by ICP-MS,H&E staining,Masson staining,immunofluorescence,q RT-PCR and Western blot.The experimental results are as follows:（1）The results of Se content and BPA content in chicken pancreas.Se content in-Se group and BPA+-Se group was significantly lower than that in control group and BPA group,and the Se content in BPA+-Se group was significantly lower than that in-Se group.Additionally,the content of BPA in BPA group and BPA+-Se group was significantly higher than that in control group and-Se group,and the content of BPA in BPA+-Se group was significantly higher than that in BPA group,indicating that BPA treatment could inhibit the absorption of Se in broiler pancreas.（2）The pancreatic pathological results of broilers showed that the pancreatic structure was clear.Acini and islet cells were full and arranged orderly,and no vacuole changes were found.Under the condition of single and combined exposure of BPA and Se deficiency,the pathological observation results showed that the pancreatic tissue was damage,the lobular space between acini was widened,the arrangement of islet cells was disordered,the shapes were different,the mitochondrial crest was broken and vacuolization appeared.Masson staining showed that the pancreatic glands were atrophic in BPA group and-Se group,and blue band collagen were observed in the acinar space.Importantly,the degree of blue collagen staining in the BPA+-Se group was higher than that in BPA group and-Se group.Above results showed that BPA and Se deficiency caused pancreatic tissue damage and fibrosis.In addition,BPA and Se deficiency had joint toxicity to broiler pancreas.（3）BPA exposure promoted the decreased activities of CAT and T-AOC,and the increased of ROS level,H2O2and MDA content in pancreas induced by Se deficiency.In vitro experiment,the results showed that the activities of CAT and T-AOC were decreased,and the levels of ROS,H2O2 and MDA were increased in HD11,CEF and coculture system were treated with BPA exposure and Se deficiency.In addition,NAC significantly decreased ROS levels,H2O2 and MDA content,and increased CAT and T-AOC activities in BPA group,-Se group and BPA+-Se group in vitro.These results showed that BPA exposure promoted oxidative stress induced by Se deficiency in the pancreatic tissue,monoculture and coculture systems of HD11 and CEF.（4）BPA exposure promoted M1/M2 macrophages imbalance induced by Se deficiency.The m RNA expression of M1 macrophage cytokines IL-1βand TNF-αwere increased,and the m RNA expression of M2 macrophage cytokine IL-10 were decreased,indicating that BPA exposure promoted Se deficiency to induce M1 macrophage polarization and secreted inflammatory cytokines.In coculture system of CEF and HD11 treated with BPA and Se deficiency,the increased number of M1 macrophages,and the increased expression of inflammatory cytokines were observed,which further proved that macrophages toward into M1phenotype after BPA exposure and Se deficiency.NAC effectively alleviated the effect of BPA exposure on macrophages toward into M1 phenotype induced by Se deficiency.（5）BPA exposure promoted macrophage polarization induced by Se deficiency through JAK2-STAT3/NF-κB signaling pathway in broiler pancreas.In HD11 treated with BPA and Se deficiency,the expression of JAK2,STAT3 and NF-κB was increased.In addition,NAC effectively alleviated the activation of JAK2-STAT3/NF-κB signaling pathway,indicating that BPA exposure promoted macrophage polarization induced by Se deficiency through JAK2-STAT3/NF-κB signaling pathway.（6）BPA exposure promoted the expression of fibrosis markers,α-SMA,FN1 and COLIA1,fibrosis regulated genes MMP2,TGF-β1 and Smad3.While the expression of TIMP2 was decreased.NAC effectively alleviated the increased expression of fibrosis markers and fibrosis regulated genes induced by Se deficiency,indicating that BPA exposure promoted fibrosis induced by Se deficiency through oxidative stress.In conclusion,BPA exposure promoted M1 macrophage polarization through ROS/JAK2-STAT3/NF-κB signaling pathway,further activating the fibrosis in Se deficient broiler pancreas.The results enrich the molecular mechanism of BPA exposure promoted pancreatic injury induced by Se deficiency,and provides a new strategy for the prevention and treatment of pancreatic fibrosis injury. |
