Roles Of Signaling Pathways Of NF-?B And Endoplasmic Reticulum Stress In Liver Toxicity Induced By Nickel Oxide Nanoparticles In Rats

Objectives: Explore the roles of oxide stress,signaling pathways of NF-?B and endoplasmic reticulum stress respectively mediated inflammatory response and apoptosis in liver toxicity induced by nickel oxide(NiO)nanoparticles in rats.Methods: 1.Total of 40 male Wistar rats were randomized into five groups,namely the control group,NiO nanoparticles groups(0.015,0.06 and 0.24 mg/kg),as well NiO micro particles group(0.24 mg/kg),to recieve intratracheal instillation twice a week for 6 consecutive weeks.All rats were killed to collect liver tissues after exsanguination via heart.2.Both weight of body and liver tissue were recorded to calculate liver coefficient to body weight 3.To explore whether NiO nanoparticles could induce liver injury,the hematoxylin and eosin(HE)staining was performed,and activities of liver enzymes were detected including alanine aminotransferase(ALT),aspartate aminotransferase(AST),alkaline phosphatase(ALP)and gamma-glutamyl transpeptidase(GGT)in serum.4.We measured levels of oxidative stress markers in liver homogenate,such as hydroxyl radical(·OH),lipid peroxide(LPO),superoxide dismutase(SOD),catalase(CAT),total antioxidant capacity(T-AOC),glutathione peroxidase(GSH-Px),as well as mRNA expression levels of heme oxygenase(HO)-1 and metallothionein(MT)-1.5.Enzyme linked immunosorbent assay(ELISA)kits for rats were used to measure concentrations of inflammatory cytokines in liver homogenate including tumor necrosis factor-alpha(TNF-?),interleukin-1?(IL-1?),IL-6,IL-4 and IL-10.We assayed mRNA and protein expression levels of TNF-?,NF-?B-inducible kinase(NIK),I?B kinase alpha(IKK-?),the inhibitor kappa B alpha(I?B-?),NF-?B,as well as phosphorylation of IKK-? and I?B-? by Wsetern blot.6.We also performed TdT-mediated dUTP Nick-End Labeling(TUNEL)staining to evaluate hepatocyte apoptosis,and detected mRNA and protein expression levels of GRP78,CHOP,IRE-1?,XBP-1S,PERK,eIF-2?,caspase-12,caspase-9,and caspase-3,as well phosphorylation of IRE-1?,PERK and eIF-2?.Results: 1.Compared to the control and NiO micro particles groups,liver coefficient to body weight increased after 0.24 mg/kg NiO nanoparticles exposure(p < 0.05).2.We observed cellular edema,hepatic sinus disappearance and infiltrated by lymphocytes in liver tissues after NiO particles exposure,as well spotty necrosis and binucleated hepatocyte in 0.24 mg/kg NiO nanoparticles group.The elevation of ALT,AST,ALP and GGT in serum appeared after 0.06 and 0.24 mg/kg NiO nanoparticles exposure compared with the control group(p < 0.05).Meanwhile activities of ALT,ALP and GGT increased in 0.24 mg/kg NiO nanoparticles group compared with NiO micro particles group.3.Levels of ·OH and LPO increased in 0.24 mg/kg NiO nanoparticles group,while CAT,GSH-Px,SOD and T-AOC were decreased in liver tissue(p < 0.05).The relative HO-1 mRNA level elevated in 0.24 mg/kg NiO nanoparticles group compared with the control group,with the reducing mRNA expression levels of MT-1(p < 0.05).4.Contents of IL-1? and IL-6 were elevated in 0.24 mg/kg NiO nanoparticles group,while IL-4 and IL-10 were reduced compared to the control group(p < 0.05).The upregulation mRNA and protein levels of TNF-?,NIK,IKK-? and NF-?B were observed in 0.24 mg/kg NiO nanoparticles group,while inducing the downregulation of I?B-?.Additionally,the protein contents of phosphorylation of IKK-?,I?B-? were elevated after NiO nanoparticles exposure.5.The rats have more TUNEL strongly positive cells in liver tissue in 0.24 mg/kg Ni O nanoparticles group than other groups,and NiO led to up-regulation in apoptotic index in 0.06,0.24 mg/kg nano groups and 0.24 mg/kg micro group(p < 0.05).Meanwhile exposure 0.24 mg/kg NiO nanoparticles could lead to increasing protein and mRNA levels of GRP78,CHOP,IRE-1?,XBP-1S,PERK,eIF-2?,caspase-9 and caspase-12,as well as protein levels of capase-3 and phosphorylation of IRE-1?,PERK and eIF-2?.Conclusions: NiO nanoparticles could induce liver injury,and its mechanisms may be related to oxide stress,signaling pathways of NF-?B and endoplasmic reticulum stress-mediated inflammatory response and apoptosis respectively.