The effect of NO-generating compounds on the lymphocytes’ ATP content and the relationship with the levels of autoantibodies to glutamate receptors in children who have suffered a traumatic brain injury

Abstract

Introduction. Inflammation and activation of the immune system are the main cause of secondary injuries in traumatic brain injury (TBI). Given the central role of nitric oxide (NO) in the neuronal Glu cascade with significant changes in the content of ATP in neurons, as well as the presence of GluRc NMDA-type in lymphocytes, it is relevant to determine the effect of NO on the lymphocytes’ adenosine triphosphate (ATP) content. The aim of the work was to determine the effect of different concentrations of NO-generating compounds (NaNO2 and S-nitrosocysteine) on the content of intra- (hcATP) and extracellular ATP (ecATP) in human lymphocytes and to establish links between NO formed during TBI and the initiation of autoimmune processes in children with TBI of varying severity. Materials and methods. Blood samples from 36 TBI children were used for analysis. Lymphocytes were isolated in a ficol gradient according to a standard procedure. The ATP concentration in the tris-acetate buffer (pH 7.76) was determined on a Lucy-1 luminometer using luciferin luciferase (Promega). The ATP concentration was expressed in nmol/mg of protein, which was determined by the Bradford method using Fluka kits. Results. An increase in the level of ATP in lymphocytes immediately after TBI was found to be a positive factor reflecting the activation of lymphocytes. At the same time, a higher level of autontibodies (aAT) to GluRc immediately after severe TBI is a favourable sign for the TBI outcome and coincides with an increase in CGAP in lymphocytes. Prolonged negative trend in ATP content in lymphocytes with similar changes in serum ATP concentrations in severe TBI is an indicator of an unfavourable outcome of severe TBI in children. Conclusion. A moderate increase in NO in the blood immediately after TBI contributes to an increase in CGAP in lymphocytes and aAT to GluRc, which activates the immune response and protects the brain from hypoxic damage.