CONICET | Buscador de Institutos y Recursos Humanos

Sjögrens syndrome (SS) is a chronic autoimmune disease which progressively destroys the salivary and lacrimal glands, leading to distressing symptoms of dry mouth and dry eyes. The nonobese diabetic (NOD) mouse, which spontaneously develops both SS-like histopathology and hyposalivation, is the most widely accepted model for SS.The aim of the present study was to determine oxidative stress parameters in salivary gland in an experimental model of SS. Male NOD mice (n= 10, 6 months) (SG) were compared to BALB/C mice (n= 12, 6 months) (CG). In order to assess the occurrence of oxidative stress the following markers were evaluated in salivary gland homogenates, lipid peroxidation (TBARS), total glutathione (GSH) and the activities of antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and thioredoxine reductase (TR). TBARS in SG was 2.89 ± 0.67 nmol/ mg protein (CG: 0.83 ± 0.11 nmol/ mg protein *p< 0.05). GSH in SG was 0.65 ± 0.11 µmol/ g (CG: 0.36 ± 0.06 µmol/g *p< 0.05). SOD activity in SG was 3.88 ± 0.58 U/ mg protein (CG 1.86 ± 0.27 U/ mg protein *p< 0.01). CAT activity in SG was 0.49 ± 0.06 pmol/ mg protein (CG 0.84 ± 0.12 pmol/ mg protein *p< 0.05). GR activity was 3.22 ± 0.55 nmol/min.mg protein in SG (CG 2.12 ± 0. 24 nm/min.mg protein, *p< 0.01). TR was 2.2 ± 0.31 nmol/min.mg protein in SG (CG 1.23 ± 0.13 nmol/min.mg protein *p< 0.005). In the present study, we found a significant increase in lipid peroxidation in salivary gland of SG compared to the corresponding controls, evidence by an increment in TBARS values. There was an increase both in GSH and in enzymatic antioxidants SOD, GR and TR, whereas CAT diminished. These findings suggested a response to chronic oxidative stress in this experimental model. Further studies are needed to clarify the biological meaning of CAT level diminution.