Research On The Role Of RIP1 And RIP3 In The Cytotoxicity Induced By Tributyltin

Tributyltin?TBT?is widely used in agriculture and industry as biocide,heat stabilizer and chemical catalyst,resulting in a large amount of its emission into the environment,causing environmental pollution.At the same time,it has been found that TBT is toxic to animals and human beings,causing endocrine toxicity,reproductive toxicity,genotoxicity,neurotoxicity,hepatotoxicity,immunotoxicity,etc.Although the ecotoxicity of tributyltin,especially the immunotoxicity,has been reported extensively,the underlying molecular mechanism remains unclear.In this study,we have investigated the mechanisms of TBT-induced cytotoxicity both in vitro and in vivo.The LDH release assay and Annexin V-FITC/PI dual staining assays were employed to detect the cytotoxicity of TBT,and the results indicated that TBT induced the cell death in a dose and time-dependent mannner.Pretreatment with RIP1 inhibitor Necrostatin-1?Nec-1?or transfection with Rip1 siRNA significantly suppressed TBT-induced cytotoxicity in J774A.1 macrophages or human embryonic kidney cell line?HEK293 cells?,suggesting that RIP1 plays an important role in TBT-induced cytotoxicity.In addition,TBT-induced cell death was also markedly inhibited in RIP3^-/-BMDMs.In agreement with in vitro results,the mortality rate induced by TBT was significantly reduced in RIP3^-/-mice or Nec-1-pretreated mice respectively.TBT-induced in vivo immunotoxic effects including leukocyte depletion and thymus atrophy were significantly attenuated in RIP3^-/-mice or WT mice treated with Nec-1.And TBT induced severe hemorrhage and hepatocyte necrosis in liver and villous atrophy and architecture destruction in small intestine,while the group of Nec-1 pretreatment or RIP3^-/-mice significantly alleviated all these damages.Taken together,these results demonstrate that RIP1 and RIP3 play important roles in TBT-induced cytotoxicity,and contribute to the regulation of TBT-induced acute toxicity and immunotoxicity in vivo.There results provide a theoretical basis for further study of other toxicological mechanisms of TBT and the toxicity mechanisms of other organotin compounds.