The Impacts of Acute High-Level Gamma Radiation Exposure on immunological parameters in the blood of rats

Gamma radiation (γR) influences cytokine regulation, with high doses (HD) producing marked biological effects under both controlled and accidental exposure scenarios. This study investigates the immunological responses to γR at doses of 2, 3, and 5 Gray (Gy) by examining T-cell receptor (TCR) mRNA expression, serum levels of Interleukin-10 (IL-10), Transforming Growth Factor-β (TGF-β), and Nitric Oxide (NO), as well as hematological parameters. These effects were compared between days 1 and 4 post-irradiation. Forty-eight male rats were randomly allocated into eight groups (six rats each), with Groups I and V serving as non-irradiated controls. Groups II-IV and Groups VI-VIII received whole-body γ-irradiation at doses of 2, 3, and 5 Gy, respectively. On days 1 and 4 after exposure, reverse transcription quantitative PCR (RT-qPCR) and standard hematological techniques were employed to assess gene expression, cytokine levels, hemoglobin concentration, hematocrit percentage, blood cell counts, and organ weights. This study demonstrates that high-dose γ-radiation (2-5 Gy) significantly (P < 0.05) increases TCR mRNA expression, hematological indices, and lymphoid organ weights, while IL-10 declines (P < 0.05), and TGF-β and nitric oxide levels are markedly elevated. Despite these observations, the null hypothesis was accepted for both time points (P > 0.05), indicating that there were no statistically significant differences across specific parameters. The observed inverse correlation between radiation exposure and lymphoid organ development supports the role of γR in altering immune-regulatory cytokines. Ultimately, higher γR doses tend to produce more pronounced immunological alterations, regardless of the intent of exposure.