Thyroid hormone-mediated regulation on intracellular glutathione concentration and antioxidant enzyme activity in lymphoid tissue of Balb/c mice

CONTIN M.; MACRI DELBONO R.; COSTILLA M.; ROMEO H.; KLECHA A.; CREMASCHI G.; TRIPODI V.; BARREIRO ARCOS M.L.

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Congreso; SAFIS + ALACF 2021 Joint meeting; 2021

SAFIS

9Thyroid hormone-mediated regulation on intracellular glutathione concentration and antioxidant enzyme activity in lymphoidtissue of Balb/c miceContin M.1; Macri Delbono R.2; Costilla M.2; Romeo H.2; Klecha A.2; Cremaschi G.2; Tripodi V.1; Barreiro Arcos M.L.21 Department of Analytical Chemistry and Physical Chemistry, School of Pharmacy and Biochemistry, University of Buenos Aires,Buenos Aires, Argentina. 2 Institute of Biomedical Research (BIOMED-CONICET), Argentine Catholic University (UCA), BuenosAires, Argentina.Introduction: Thyroid hormones (TH) regulate metabolism and redox status in most tissues. We previously demonstrated that THincrease reactive oxygen species (ROS) in lymphoid cells. However, the antioxidant defense mechanisms involved in ROSclearance have not yet been elucidated. Objectives: To analyze the intracellular glutathione content, the GSH/GSSG ratio and theactivity or expression of antioxidant enzymes in lymphoid tissue from euthyroid and hyperthyroid mice. Methods:Hyperthyroidism was induced in Balb/c mice by treatment with thyroxine in drinking water (12 mg/ml) for 40 days. Lymphoidcells from lymph nodes (LN) and spleen (S) were purified for biological assays. Assessment of GSH and GSSG was performed byliquid chromatography and tandem mass spectrometry (HPLC-MS/MS). Catalase (CAT) and Glutathione peroxidase-1 (GPx-1)expression was quantified by real-time PCR and western blot. The conversion of H2O2 to molecular oxygen by CAT was determinedby spectrophotometry. ROS were evaluated by DCFH-DA staining and flow cytometry. Results: We found that GSH and GSSG wereincreased in LN and S from hyperthyroid mice, and the GSH/GSSG ratio was similar to euthyroid mice (% increase- GSHLN:30.2±2.1,GSHS:29.6±1.8; GSSGLN:32.4±2.9, GSSGS:31.7±2.7; n=5; p<0.05). The total intracellular glutathione content was increased in bothtissues. In vitro treatment of lymphoid cells from hyperthyroid mice with a glutathione synthesis precursor (N-acetyl-cysteine,2mM) increased GSH content and decreased ROS production. CAT activity was increased in LN and S from hyperthyroid mice aswell as its genomic and protein expression (% increase- ActivityLN:93.4±7.1, ActivityS:82.3±6.7; mRNALN:85.1±6.2,mRNAS:147.2±9.7; ProteinLN:154.3±9.7, ProteinS:165.7±10.1; n=6; p<0.05). GPx-1 expression was increased in hyperthyroid mice(% increase- mRNALN:43.7±3.1, mRNAS:39.8±4.7; ProteinLN:47.6±5.1, ProteinS:71.1±6.6; n=6; p<0.05). In vitro treatment oflymphoid cells from euthyroid mice with an oxidative stress inducer (H2O2, 250μM) increased the genomic expression ofantioxidant enzymes. Conclusions: TH induce oxidative stress and regulate the antioxidant system in lymphoid tissue cells.