Introduction. Despite the dominance of mild traumatic brain injury (mTBI) in the structure of TBI, the biochemical parameters of mild brain damage in brain concussions have not been sufficiently studied. This fact makes it difficult to predict the outcomes of concussions that are part of the mild form of TBI. Aim of the work: identify changes in markers of brain damage in children’s blood who underwent mTBI with an emphasis on brain concussions, and compare the indicators with a group of children with moderate TBI (mdTBI).Materials and methods. One hundred thirty six children were examined, including 35 children with concussion (15 points on the Glasgow Coma Scale (GCS)), 65 children with mTBI (13–14 points on the GCS) and 36 children with mdTBI (9–12 points on the GCS). In the first 1–2 days after TBI, the content of such markers of brain damage as glial protein S100b, acidic fibrillary protein GFAP, αII-spectrin (spectrin breakdown product — SBDP-145), 2 types of autoantibodies (aAT) to glutamate receptors (GluRc) — NMDA (NR2) and AMPA (GluR1) subtypes, degradation products of these receptors — peptides corresponding to the N-terminal regions of NMDA and AMPA GluRc (NR2 and AMPA1 peptides), as well as the content of nitric oxides (NOx) (NO2– + NO3–) and 3-nitrotyrosine (NT). The concentrations of these compounds in blood serum/plasma were determined by enzyme immunoassays.Results. In the first days after TBI, a significant proportion of children with mTBI showed an increase in the content of oxidative stress markers (NOx, NT) and a significant increase in the level of aAb to NMDA GluRc in the blood. In children with mdTBI, indicators of brain damage (S100b, GFAP, αII-spectrin, NOx, and NMDA GluRc degradation products — NR2 peptides) exceeded those in children with mTBI. On the contrary, the level of aAb to NMDA GluRc and the degradation products of AMPA GluRc — AMPA 1 peptides had maximum values in the group of mTBI in children with brain concussions.Conclusion. It has been shown that in many children with mTBI (GCS = 14–15), most of the indicators are at the upper limit or exceed the upper limit of the normal values, which indicates a different degree of brain response to mild traumatic stress. In children with concussion, a high level of aAb to NMDA GluRc against the background of a low content of their degradation products, NR2 peptides, in the first days after TBI may indicate more pronounced compensatory mechanisms aimed at reducing NMDA GluRc hyperstimulation in mTBI. At the same time, a higher content of AMPA 1 peptides in children with concussions may be the initial signs of diffuse axonal damage.Contribution: Sorokina E.G., Reutov V.P., Semenova Zh.B. — concept, design and writing the text; Semenova Zh.B., Sorokina E.G., Karaseva O.V. — collection and processing of the material; Smirnov I.E. — editing the text. All co-authors — approval of the final version of the article, responsibility for the integrity of all parts of the article.Acknowledgments. The study had no sponsorship.Conflict of interest. The authors declare no conflict of interest.

Received: January 18, 2026Accepted: February 10, 2026Published: February 27, 2026