Objective: The purpose of this study was to analyze the effect of oral administration of radioiodine (I-131) on the immune responses (interleukin 6 and 10) as biodosimetry markers and to support clinical trials of I-131 solution.
Methods: The design of this study was an in vivo experimental study using twenty-seven male rats (Rattus norvegicus strain Sprague-Dawley) given 100 μL of I-131 solution at a dose of 260 μCi. Blood plasma was taken at 0.25, 0.5, 1, 3, 24, 48, 120, and 168 hours post oral I-131 administration, respectively. Rats without radioiodine administration as a control group. The levels of IL-6 and IL-10 were measured using the enzyme-linked immunosorbent assay (ELISA) method. Statistical analysis was carried out with one-way ANOVA using SPSS version 25 software.
Result: IL-6 level began to significantly increase at 0.25 hours post administration of I-131 (14.4 pg/mL ± 2.52 pg/mL, p=0.02). During 7 days of observation, IL-6 levels had 2 peaks of highly significant increase at 0.5 hours (43.57 ± 5.28, p<0.001) and 120 hours (24.08 ± 2.69, p<0.001 compared to control (5.44 ± 0.95 pg/mL). IL-10 level began to significantly increase at 0.25 hours (30.32 ± 3.22 pg/mL, p=0.03) compared to controls (20.61 ± 1.59 pg/mL).
Conclusion: The highest increase in IL-6 and IL-10 levels occurred respectively in the first 0.5 hours 8 times and in the first 0.25 hours 1.47 times compared to controls. Internal irradiation with radioiodine resulted in a significant increase in immune cells in exposed blood plasma characterized by the production of the cytokines IL-6 and IL-10. This appears to be a response of immune cells to reduce or stop inflammatory reactions through the release of anti-inflammatory cytokines in an effort to prevent excessive inflammatory responses that can damage cells and tissues.
Keywords: Immune responses; Interleukin 6; Rats blood plasma; interleukin 10; radioiodine.