Effects of Taurine in Cellular Responses to Oxidative Stress in Young and Middle‐Aged Rat Liver

Abstract

Aging is related with an increased cellular level of lipid peroxides and reactive oxygen species (ROS). The useful effects of taurine as an antioxidant in biological systems have been attributed to its capability to stabilize biomembranes, to scavenge ROS, and to decrease the peroxidation of unsaturated membrane lipids. The aim of the present study was to investigate the effects of taurine on malondialdehyde (MDA), glutathione (GSH), glutathione peroxidase (GPx), thioredoxin reductase (TR), and endothelial nitric oxide synthase (eNOS) in young and middle-aged rat liver. There was not a significant difference in liver MDA levels between the control groups of young and middle-aged rats (P > 0.05). However, liver GSH levels, and GPx and TR activities between the control groups of young and middle-aged rats were significantly different (P < 0.05). Liver MDA level was significantly lower in the taurine group of middle-aged rats (P < 0.05). Liver GSH levels, and GPx and TR activities were significantly increased in the taurine group of middle-aged rats when compared to the control group (P < 0.05). Liver MDA level was significantly lower in the taurine group of young rats than the ones in the control group (P < 0.05). Liver TR activity was significantly increased in the taurine group of young rats when compared to the control group (P < 0.05). Liver GPx activity was not statistically different between the taurine and the control groups in young rats (P > 0.05). Liver GSH levels were not different between the young taurine and the control groups (P > 0.05). Immunohistochemical studies exhibited no change in eNOS activity after taurine injection in young rats. However, in middle-aged rats, taurine lowered the eNOS reactivity to the same level found in young rats. These results suggested that exogenous taurine might play a role in aging by means of its reducing effects on free radical levels in parallel to an increase in the antioxidant capacity.

Reactive oxygen species: A double-edged sword in oncogenesis

“…Peroxidation by ROS alters the amounts of unsaturated fatty acids and proteins in the cell membrane and thus affects membrane fluidity. In addition, with aging, humans tend to show an increased affectability of lipid peroxides caused by ROS [1] . Recent research has indicated that ROS also play a critical role in the energy dysfunction of mitochondria caused by ethanolinduced gastric mucosa injury [2] .…”

The in Vitro Effect of Taurine on Boar Spermatozoa Quality

“…Taurine has been repeatedly shown to promote the activity of antioxidant enzymes such as thioredoxin reductase (Yildirim et al, 2007), superoxide dismutase (Higuchi et al, 2012),…”

Environmental Factors, Oxidative Stress, and Adverse Developmental Outcomes

“…Taurine is synthesized from cysteine (Stipanuk 2004) via the actions of cysteine dioxygenase (CDO), which gives rise to cysteinesulnate, and then cysteinesulnate decarboxylase (CSD) decarboxylates cysteinesulnate to hypotaurine (Ubuka et al 2008). Taurine protects cells from ROS damage by upregulation of key antioxidant enzymes that control ROS production (Yildirim et al 2007). Hydrogen sulfide (H 2 S), a signaling molecule (Li and Moore 2007), is formed from cysteine by pyridoxal-5 0 -phosphate (PLP)-dependent enzymes, including cystathionine b-synthase (CBS) and cystathionine g-lyase (CSE) (Kimura 2011).…”