EFFECTS OF OXIDATIVE STRESS ON LYMPHOCYTE FUNCTIONALITY IN A MURINE MODEL OF HYPERTHYROIDISM. ROLE OF THE CELLULAR ANTIOXIDANT SYSTEM IN THE SCAVENGING OF OXYGEN FREE RADICALS

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

Ciudad de buenos Aires

Congreso; Reunión de Sociedades de Biociencias 2020; 2020

Reunion de Sociedades de Biociencias 2020

Introduction: Thyroid hormones increase cellular metabolism and theproduction of reactive oxygen species (ROS). ROS could act as a signalingmolecule involved in cell functionality or exert cytotoxic actions depending onits intracellular concentration. The harmful effects of ROS are counteracted bythe cellular antioxidant system. Objective:To study the effects of oxidative stress on lymphocyte functionality inhyperthyroid mice, analyzing the role of antioxidant enzymes in the scavengingof ROS. Methods: Balb/c mice weretreated with placebo (euthyroid) or T4 (12 mg/l drinking water for 30 days-hyperthyroid). ROSwere evaluated by DCFH-DA staining and flow cytometry. The expression ofcatalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) wasdetermined by qPCR and WB. Apoptosis was evaluated byAnnexin V-PI,Rhodamine-123 or Hoechst-33342 staining followed by flow cytometry orfluorescence microscopy. The number of follicles in lymphoid tissue sectionsstained with hematoxylin-eosin was determined by microscopy. Cell size andgranularity was evaluated by flow cytometry. Proliferation was evaluated by incorporation of [3H]-thymidine.Results: We found an increasedproduction of ROS in the lymph nodes (LN) and spleen (S) of hyperthyroid mice (%increase LN:60.6±5.1; S:63.5±5.9, p<0.05) that was correlated with anincreased genomic and protein expression of CAT and GPx (CATRNAm% LN:85.1±6.2,S:147.2±9.7; CATprotein% LN:154.3±9.7, S:65.7±5.8; GPxRNAm%LN:43.7±3.1, S:39.8±4.7; GPxprotein% LN:47.6±5.1, S:71.1±6.6; p<0.05).We did not find significant differences in theexpression of SOD. Apoptosis was similar in both groups. Hyperthyroid mice hadhypertrophied lymphatic organs, more lymphoid follicles and lymphoid cells inactive cell proliferation. Conclusions:Antioxidant enzymes partially decrease ROS, avoiding their cytotoxic effect onlymphoid cells. ROS could participate in the signaling pathways involved inlymphocyte functionality.&lt;!-- /* Font Definitions */@font-face{font-family:Arial;panose-1:2 11 6 4 2 2 2 2 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:3 0 0 0 1 0;}@font-face{font-family:Arial;panose-1:2 11 6 4 2 2 2 2 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:3 0 0 0 1 0;}@font-face{font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:3 0 0 0 1 0;} /* Style Definitions */p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin:0in;margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:11.0pt;font-family:Calibri;mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;mso-ansi-language:ES;}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-size:11.0pt;mso-ansi-font-size:11.0pt;mso-bidi-font-size:11.0pt;font-family:Calibri;mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;mso-ansi-language:ES;}size:8.5in 11.0in;margin:1.0in 1.25in 1.0in 1.25in;mso-header-margin:.5in;mso-footer-margin:.5in;mso-paper-source:0;}div.WordSection1{page:WordSection1;}