Expressão de citocinas inflamatórias no hipocampo e análise comportamental em camundongos adultos irradiados no crânio com baixas doses de raios X quando neonatos

Abstract

Ionizing radiation is widely used in clinical practice, particularly in imaging procedures such as computed tomography, including in neonatal patients. However, despite technological advances that allow dose reduction, the long-term biological effects of early-life radiation exposure—especially in developing brain structures such as the hippocampus—are still not fully understood. This study investigated the effects of low doses of ionizing radiation on the brains of neonatal male and female mice, focusing on inflammatory cytokine expression in the hippocampus and behavioral changes observed in adulthood. To this end, animals were exposed to X-ray ionizing radiation at doses equivalent to those used in pediatric head CT scans during the neonatal stage (PND10), with exposures of approximately 25 mGy, 60 mGy, and 100 mGy. Upon reaching adulthood (PND81), the animals underwent behavioral assessments using the Open Field and Object Location Recognition tests, which allowed the analysis of potential motor and cognitive alterations. In parallel, RT-qPCR was performed to quantify the expression of pro- and anti-inflammatory genes, along with biochemical analyses using TBARS, SOD, catalase, and GPx assays to evaluate oxidative stress and redox imbalance in hippocampal tissue. The results revealed behavioral alterations, particularly an increase in anxiety-like behavior in male mice exposed to approximately 100 mGy, and changes in SOD and TBARS levels at the 60 mGy dose—markers of oxidative stress. These changes were restricted to male mice, highlighting not only the direct effects of radiation but also suggesting a potential influence of sex-specific factors in the long-term response to radiation-induced damage. This study contributes to the understanding of the biological effects of early-life exposure to low-dose ionizing radiation, typical of pediatric head CT examinations.