The role and mechanisms of thioredoxins in arsenic-induced liver injury

Abstract

Thioredoxin (TRX) is an important component in the thioredoxin system which is comprised of TRX, thioredoxin reductase (TRXR), and reduced coenzymeⅡ (NADPH). TRX is widely expressed in nearly all living cells and functions as protein disulfide reductase involving in many important biological processes, including redox signaling, the inhibition of apoptosis, regulation of transcription factors, and immune responses. TRX plays an important role in the regulation of the intracellular redox state against oxidative stress. Epidemiological studies showed that high arsenic exposure led to significant increases of serum levels of reactive oxygen species and decreases of antioxidant levels. Liver cell injury induced by arsenic via oxidative stress has been extensively studied. Oxidative stress in the process of lipid peroxidation has been widely recognized as one of the main mechanisms of arsenic poisoning. This process can produce a variety of free radicals and non-radical products those cause liver cell dysfunction or directly attack liver cells causing liver damage. Therefore, we hypothesized that TRX could play an important protective role in arsenic-induced liver injury. This paper reviews the antioxidative role of TRX in the liver injury caused by arsenic poisoning. Key words: Arsenic poisoning; Liver injury; Thioredoxin; Oxidative stress