NITRIC OXIDE SYNTHESIS INTENSITY ASSESSMENT BY THE CONTENT OF ITS TERMINAL STABLE METABOLITES IN THE BLOOD OF RATS...

Area of Science:

• Toxicology
• Biochemistry
• Physiology

Background:

• Nitric oxide (NO) plays a crucial role in various physiological processes.
• Sodium fluoride (SF) is a common environmental toxicant with known health effects.
• Understanding NO synthesis alterations under SF exposure is vital for toxicological assessment.

Purpose of the Study:

• To investigate the impact of varying sodium fluoride (SF) doses on nitric oxide (NO) synthesis in rats.
• To evaluate the changes in NO metabolites (nitrite and nitrate) in blood plasma following SF exposure.
• To elucidate the temporal dynamics of NO production and its potential role in SF-induced toxicity.

Main Methods:

• Adult Wistar rats were orally administered aqueous sodium fluoride (SF) solutions daily for 60 days.
• Three doses of SF were used: 1/10, 1/100, and 1/1000 of the DL50 (20 mg/kg, 2 mg/kg, 0.2 mg/kg).
• Blood plasma levels of nitrite and nitrate anions were measured to assess NO synthesis intensity.

Main Results:

• SF administration at 1/10 and 1/100 DL50 doses increased blood nitrite and nitrate levels within the first 30 days.
• This initial increase suggests excessive NO production, potentially a compensatory response.
• After prolonged exposure, nitrite and nitrate levels decreased, indicating reduced NO generation.

Conclusions:

• Early-stage SF exposure may induce a compensatory increase in NO synthesis.
• Long-term SF exposure leads to a decline in NO production, possibly due to increased peroxynitrite formation and antioxidant enzyme deficiency.
• These findings highlight the complex, dose-dependent, and time-dependent effects of SF on NO metabolism and oxidative stress.