Long-term consequences of acute toxic prenatal hypoxia induced by sodium nitrite in rat experiments

Abstract

   Introduction. Gestational hypoxia plays an important role in fetal development, as it causes the development of oxidative stress and delayed psychomotor development.   The aim of the study was to evaluate the prenatal effect of sodium nitrite on indices characterizing orienting and exploratory activity, mental activity and the degree of hypoxia in rat offspring.   Materials and methods. Acute hypoxia was modeled by administration of sodium nitrite at a dose of 30 mg/kg intramuscularly to five pregnant rats during 16–19 days of gestation. Five females constituted a control group. In 50 born rats, orientation and exploration activity, cognitive functions, intensity of lipid peroxidation and glycolysis were studied.   Results. The offspring of females that underwent acute hypoxia significantly lagged behind in the positive dynamics of body weight gain compared to control individuals. Thirty-day-old rats showed a pronounced disorder of the structure of behavioral pattern, learning process and long-term memory, increased content of diene conjugates, malonic dialdehyde and the level of lactate dehydrogenase activity in blood.   Discussion. It was found that offspring whose mothers suffered acute hypoxia of toxic genesis developed pronounced behavioral disorders of psychomotor agitation and cognitive dysfunction characterized by decreased learning ability and impaired long-term memory. The content of primary and secondary products of lipid peroxidation and lactate dehydrogenase was increased in rats. The development of cellular oxidative stress under conditions of intrauterine hypoxia leads to oxygen deficiency in the fetus and a switch from tissue respiration to glycolysis, which underlies CNS damage.   Conclusion. It was shown that sodium nitrite administration during the period from the 16th to the 19th day of gestation caused hyperactivity, depressed emotional status, and decreased orienting and exploratory activity and the ability to learn and retain a memory trace in rat offspring. Increased levels of diene conjugates and malonic dialdehyde, lactate dehydrogenase activity were observed in rats.