INDUCTION OF OXIDATIVE STRESS IN LYMPHOID TISSUE FROM MURINE MODELS OF HYPOTHYROIDISM: TREATMENT WITH PROPYLTHIOURACIL VERSUS THYROIDECTOMY

ROMEO, H; KLECHA, A; CREMASCHI, G; BARREIRO ARCOS, ML

Ciudad de buenos Aires

Congreso; Reunión de Sociedades de Biociencias 2020; 2020

Reunion de Sociedades de Biociencias 2020

Introduction: Hypothyroidisminduced by antithyroid drugs increases reactive oxygen species (ROS). Someauthors attribute the increase in ROS to a decrease in the intracellularconcentration of non-enzymatic antioxidants and other authors to a cytotoxiceffect of the drug in the liver. Objective:1- Analyze whether the increase in ROS is a pathological condition inducedby hypothyroidism or is due to the direct action of antithyroid drugs; 2- Evaluatethe effect of hypothyroidism on lymphocyte functionality. Methods: Hypothyroidism was induced in Balb/c mice by treatmentwith propylthiouracil (PTU; 0.5 g/l drinking water for 15 days) orthyroidectomy. Thyroid hormone levels were quantified by RIA. ROS wereevaluated by DCFH-DA staining and flow cytometry. Liver damage was evaluated intissue sections stained with hematoxylin-eosin and Masson?s Trichome. Thenumber of lymphoid follicles was determined in sections of lymph nodes or spleenstained with hematoxylin-eosin. Apoptosis of lymphoid cells was quantified by flowcytometry and cell proliferation was evaluated by incorporation of [3H]-thymidineinto DNA. Results: We found thatboth, hypothyroid mice by treatment with PTU and thyroidectomized (Thy) had anincreased production of ROS in lymph nodes (LN) and spleen (S) compared toeuthyroid mice [% increase (LN) PTU: 68.5±8.4, Thy: 62.2±6.5 and % increase (S)PTU: 50.3±5.8, Thy: 62.6±7.3 (p<0.05; n=9)]. We did not observe liver tissuedamage in the mice treated with PTU. Hypothyroid mice had smaller lymphatic organs, a lowerdensity of lymphoid follicles/field and a decreased proliferative capacityagainst mitogenic stimuli compared to euthyroid controls. Apoptosis inhypothyroid mice was similar to controls. Conclusions: Hypothyroidisminduced by PTU or thyroidectomy increases ROS production in lymphoid tissue andhas negative effects on lymphocyte functionality. PTU did not induce livercytotoxicity in our study model<!-- /* 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:"Cambria Math";panose-1:2 4 5 3 5 4 6 3 2 4;mso-font-charset:1;mso-generic-font-family:roman;mso-font-format:other;mso-font-pitch:variable;mso-font-signature:0 0 0 0 0 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;}