Toxicological Effect Of Excess Manganese On NF-κB/iNOS-COX-2 Signaling Pathway And HSPs In Chicken Testes

Manganese(Mn) is one of the most important trace elements in animals and human beings. However, excess Mn is harmful to animals and human beings, and the research about Mn on the reproductive system of chicken inflammatory and heat shock protains(HSPs) is still unclear. The aim of this study was to investigate the effect of manganese on NF-κB/i NOS-COX-2 signal transduction pathway and HSPs in chicken testes. 180 hyline male chickens at 7 days of age were fed either commercial diet or Mn Cl2-added commercial diet containing 600, 900, and 1800 mg/kg Mn at 30, 60, and 90 days, respectively. The mRNA expression of nuclear factor-κB(NF-κB), tumor necrosis factor-α(TNF-α), cyclooxygenase-2(COX-2), inducible nitric oxide synthase(i NOS) and HSP27, HSP40, HSP60, HSP70, HSP90, nitric oxide(NO) content, i NOS activity, histopathology and ultrastructure were examined in chicken testes. The results showed that:(1)Excess Mn up-regulated mRNA expression of NF-κB, COX-2, TNF-α, and i NOS. Mn had a time-dependent effect on NF-κB and TNF-α mRNA expression. Excess Mn up-regulated NO content, and iNOS activity at 60 th and 90 th day. Mn had a dose- and time-dependent effect on NO content and iNOS activity. Mn exposure resulted in inflammatory injury of chicken testis tissue through NF-κB/i NOS-COX-2 signaling pathway.(2)Excess Mn depressed mRNA express of HSP40 and HSP60, and induced mRNA express HSP27, HSP70 and HSP90. Mn had a time- and dose-dependent effect on them.(3)Excess Mn-induced histological and ultrastructural changes of chicken testes, and the damagement were dose-, and time-dependent.