The Role of Ap-1 Transcription Factor Activation in the Changes of Production and Utilization of Nitric Oxide in the Gastric Mucosa of Rats Under Conditions of Chronic Fluoride Intoxication

Abstract

Millions of people are affected by excessive fluoride intake. The effect of fluorides on the activation or inhibition of redox-sensitive transcription factors remains poorly understood. The aim of this research is to examine the effect of activation of the transcription factor AP-1 on changes in the activity of inducible NO synthase and constitutive isoforms of NO synthase, concentrations of peroxynitrites of alkali and alkaline earth metals, concentrations of nitrites and nitrosothiols in the gastric mucosa of rats under conditions of chronic fluoride intoxication. The study was conducted on 18 adult male Wistar rats weighing 220-260 g. Experimental animals were randomly divided into 3 groups of 6 animals each: control, chronic fluoride intoxication group and AP-1 transcription factor blockade group. Chronic fluoride intoxication was simulated by the administration of sodium fluoride at a dose of 10 mg / kg for 30 days. AP-1 blockade was performed by administering SR11302 at a rate of 15 mg / kg twice a week. In the gastric mucosa, the following was studied: the activities of constitutive and inducible isoforms of NO synthase, the concentration of nitrites, peroxynitrites and nitrosothiols. Chronic fluoride intoxication reduces the activity of constitutive NO synthases by 37.73% and increases the activity of inducible NO synthase by 1.61 times. The concentration of peroxynitrites increases by 2.68 times, nitrites – by 1.74 times, and nitrosothiols – by 1.88 times. Blockade of AP-1 reduces the activity of inducible isoform by 2.11, does not affect the activity of constitutive isoforms, and reduces the concentration of peroxynitrites by 1.98 times, nitrites – by 2.10 times, and nitrosothiols – by 2.37 times. Activation of the transcription factor AP-1 under conditions of chronic excessive fluoride intake leads to increased production of nitric oxide in the gastric mucosa of rats, enhances its oxidation to nitrites, promotes the formation of nitrosyl groups in the reaction with low molecular weight donors of thiol groups and increases the peroxidation of nitric oxide with the formation of peroxynitrite.