Avaliação dos impactos do envelhecimento induzido por D-galactose no timo de camundongos

Abstract

The deleterious changes in the immune system that accompany aging are known as immunosenescence, and may be related to the incidence of infectious, metabolic and autoimmune diseases, cancer and neurological disorders in elderly people. Understanding how different markers of immunosenescence are regulated and their heterogeneity in differential states of senescence is essential for choosing the correct methods to measure them, and, consequently, treat them. Therefore, this work aimed to investigate changes in the thymus in a murine model of early-induced aging with D-galactose (D-gal), more specifically verifying the relative weight, cellularity and gene expression in the thymus and the animals’ weight. For this purpose, male mice of the C57BL/6 lineage were used and treated with D-gal (200 mg/kg) or saline solution (non-senescent controls), subcutaneously, daily, for 45 days. After the last day of treatment, the animals were euthanized, the thymus was removed, weighed and subsequently macerated, and the cells were counted in a Neubauer chamber using the 0.02% Trypan blue exclusion method. Furthermore, real-time quantitative PCR was performed to analyze the gene expression of genes for antioxidant enzymes (Sod2, Cat, Gpx) and proteins related to cellular senescence (P21 and Tnf-a) and thymic physiology (Il-7, Foxn1 and Pparg). Treatment with D-gal did not change the animals’ weight, the relative weight or the total cellularity of the thymus, but it decreased the expression of the gene for the antioxidant enzyme catalase (Cat) and increased that of the senescence marker gene P21.