Evidence of hippocampal astrogliosis and antioxidant imbalance after L-tyrosine chronic administration in rats

Carvalho-Silva, Milena; Gomes, Lara M.; Prá, Samira Dal-Toé De; Wessler, Leticia B.; Schuck, Patrícia Fernanda; Scaini, Giselli; de, Andreza Fabro; Blum-Silva, Carlos H.; Reginatto, Flávio Henrique; Oliveira, Jade de; Streck, Emílio L.

doi:10.1007/s11011-019-00511-3

Cited by 5 publications

(1 citation statement)

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“…Glutathione reductase (GR) activity was measured by monitoring NADPH consumption [ 38 ]. Brains from control and L-KYN groups were homogenized 1:10 ( w / v ) in a buffer containing 3.09 µM KH 2 PO 4 , 1.90 µM Na 2 HPO 4 , 0.05% Triton 100×, pH 7, then samples were centrifuged at 10,000× g for 30 min.…”

Section: Methodsmentioning

confidence: 99%

On the Antioxidant Properties of L-Kynurenine: An Efficient ROS Scavenger and Enhancer of Rat Brain Antioxidant Defense

et al. 2021

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L-kynurenine (L-KYN) is an endogenous metabolite, that has been used as a neuroprotective strategy in experimental models. The protective effects of L-KYN have been attributed mainly to kynurenic acid (KYNA). However, considering that L-KYN is prone to oxidation, this redox property may play a substantial role in its protective effects. The aim of this work was to characterize the potential impact of the redox properties of L-KYN, in both synthetic and biological systems. First, we determined whether L-KYN scavenges reactive oxygen species (ROS) and prevents DNA and protein oxidative degradation in synthetic systems. The effect of L-KYN and KYNA (0.1–100 µM) on redox markers (ROS production, lipoperoxidation and cellular function) was compared in rat brain homogenates when exposed to FeSO4 (10 µM). Then, the effect of L-KYN administration (75 mg/kg/day for 5 days) on the GSH content and the enzymatic activity of glutathione reductase (GR) and glutathione peroxidase (GPx) was determined in rat brain tissue. Finally, brain homogenates from rats pretreated with L-KYN were exposed to pro-oxidants and oxidative markers were evaluated. The results show that L-KYN is an efficient scavenger of ●OH and ONOO−, but not O2●– or H2O2 and that it prevents DNA and protein oxidative degradation in synthetic systems. L-KYN diminishes the oxidative effect induced by FeSO4 on brain homogenates at lower concentrations (1 µM) when compared to KYNA (100 µM). Furthermore, the sub-chronic administration of L-KYN increased the GSH content and the activity of both GR and GPx, and also prevented the oxidative damage induced by the ex vivo exposure to pro-oxidants. Altogether, these findings strongly suggest that L-KYN can be considered as a potential endogenous antioxidant.

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Section: Methodsmentioning

confidence: 99%