The mRNA expression of genes encoding selected antioxidant enzymes and thioredoxin, and the concentrations of their protein products in gingival crevicular fluid and saliva during periodontitis

Background. The activity of antioxidant enzymes in periodontitis is reduced, but results vary between studies and are subject to bias. In turn, the expression of genes encoding antioxidant factors has not been examined yet. Objectives. This is the first study to evaluate the expression of genes encoding superoxide dismutase 1 (SOD1), glutathione peroxidase 1 (GPX1) and thioredoxin 1 (TXN1) in the saliva and gingival tissue of patients with periodontitis. The activity of the antioxidant enzyme protein products in the unstimulated and stimulated saliva and the gingival crevicular fluid (GCF) of patients with periodontitis was also investigated. Material and methods. The prospective study involved 65 patients with periodontitis, who were divided into groups depending on the disease stage, and a control group of 31 age- and gender-matched healthy patients. Results. We demonstrated that the expression of genes encoding GPX1 and TXN1 in saliva was significantly higher, and the expression of genes encoding SOD1, GPX1 and TXN1 in the gingival tissue was significantly lower in periodontitis patients as compared to the control group. We noted a lower activity of GPX1 in unstimulated saliva, of SOD1 in stimulated saliva and of both antioxidant enzymes in GCF in patients with periodontitis. Conclusions. The GPX1 transcriptome and its activity in the salivary and GCF proteome appear to be dependent on the oxidative stress related to the destructive inflammatory changes in periodontitis.