Dose Dependent Immune and Antioxidant in Responses to Low Dose Radiation

Radiotherapy is the cornerstone in cancer treatment; it aims to deliver the prescribed treatment dose to the tumor tissue with consideration of reducing the toxicity risk of scattering radiation on the surrounding healthy organs. Recently, low dose radiation has been playing a crucial role in the treatment of benign tumors and other diseases such as Orthroathrites. Low-dose radiation is believed to exert a positive influence on biological systems, a concept explained by the theory of radiation hormesis. This study aims to investigate the impact of different low doses on the immunity and antioxidant activities of the biological systems. An animal model (Rats) was exposed to whole body irradiation to 10 cGy, 25 cGy and 50 cGy in different groups and after that, blood samples were collected after 24 hours from irradiation to measure CD4+ and CD8+ T cell levels by flow cytometry, while antioxidant enzymes (SOD, CAT, and GPx) were assessed using a spectrophotometer. The results indicated that there is a gradually increase with the exposed radiation with comparing to the control group as 34.10 ± 0.06, 39.17 ± 0.010, 49.33 ± 0.045, 62.23 ± 0.009 for CD4+ and 29.23 ± 0.023, 32.83 ± 0.035, 46.40 ± 0.016 and 55.47 ± 0.022 for CD8+ for control, 10 cGy, 25 cGy and 50 cGy groups respectively. The anti-oxidant activities exhibit increasing in, SOD, CA and, GPx in compare to the control Group .The recorded values of SOD, Ca, and GPX were 12.75±1.15, 66.98±0.97, and 33.28±1.48 U/ml for 10 cGy group, while they were 5.97 ± 0.56, 43.35 ± 1.93 and, 21.10 ± 1.30 U/ml for the 25 cGy group and, they were 4.18 ± 0.56, 29.45 ± 1.09, and 13.57 ± 0.65 U/ml for the 50 cGy group. In addition to statistical significance, the magnitude of treatment effects was quantified using effect size analysis, allowing clearer interpretation of how meaningfully each radiation dose influenced immune and antioxidant responses. The effect size has been calculated for all parameters, it was Cohen’s d >>>0.8 for CD4+, CD8+ in 10 cGy, 25 cGy and 50 cGy and antioxidant levels in 10 cGy only and Cohen’s d <<<0.8 in antioxidant levels in 25 cGy and 50 cGy levels which means that 10 cGy has a radiobiological significant impact. In general, based on these results, it can be concluded that 10 cGy can induce a hormesis effect while 25 cGy and 50 cGy have a beneficial effect on immunity but, it induces oxidative stress in the biological system. These findings support a hermetic model and suggest a critical dose threshold that separates beneficial from harmful effects. This insight may inform dose optimization strategies in radiotherapy and radioprotection.