Radio-adaptive Response Induced by Low-dose Ionizing Radiation in Innate Immunity for Radiotherapy

Abstract

Radio-adaptive response (RAR) is a mechanism by which low doses of ionizing radiation (IR) protect cells from subsequent high doses. This study aimed to compare the immuno-radiological effects of 0.25, 0.5, and 5 Gy to 0.25 or 0.5 Gy as priming and 5 Gy as challenging doses. Thirty-five rats were irradiated whole-body with 0.25 and 0.5 Gy followed by 5 Gy, and the same single IR doses with non-irradiated animals serving as controls. Serum interferon-gamma (INF-γ), interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), nitric oxide (NO), and malondialdehyde (MDA) levels were measured 4 d post both priming and challenge doses. A 0.25-Gy priming dose significantly (P < 0.05) reduced serum TNF-α, MDA, and NO levels compared to all single-irradiated groups. Surprisingly, there was no difference in IFN-γ serum levels between the RAR-induced and non-irradiated groups (P ≥ 0.05). Compared to the same low priming dose (0.25 and 0.5 Gy), the effect of the challenging dose (5 Gy) remains unchanged or decreases. Serum IFN-γ, MDA, and NO concentrations, on the other hand, were significantly (P < 0.05) lower in the 0.5 Gy pre-challenging dose, whereas IL1β had no effect (P ≥ 0.05) compared to 5 Gy alone. The post-RAR group had significantly (P < 0.05) lower oxidative stress indicators than the other irradiation groups. The findings suggested that priming with low IR could help mitigate the negative effects on the hematopoietic system. Finally, RAR has significantly impacted endogenous cytokines, oxidative stress biomarkers, and lipid peroxidation parameters. RAR can improve patients' radiological safety profiles by mitigating adverse radiotherapy effects.

Role of TLR4 signaling pathway in the mitigation of damaged lung by low‐dose gamma irradiation

“…LDR promotes a radio‐adaptive response, which can ameliorate the damaging effect of HDR, ameliorate the short‐term efficacy of radiotherapy, and increase the survival of lung cancer patients 47 . Hussien and Rashed 48 reported that LDR enhances a radio‐adaptive response against HDR‐induced damage via immune development; it is a promising preclinical model that might be used to reduce the undesirable effects of radiotherapy on normal but not the tumor cells. Also, the histopathological results confirmed the biochemical findings.…”

Deficiency of salt‐inducible kinase 2 (SIK2) promotes immune injury by inhibiting the maturation of lymphocytes

“…Many studies have confirmed that ionizing radiation (IR) can induce immune damage in the system 26–28 . Localized 8.7 cGy over 10 days resulted in longstanding systemic lymphoid hypoplasia and low dose radiation could induce immune suppression 29,30 . However, the mechanism is still unclear, and it is important to find a target that can evaluate the application value of radiation‐induced immune injury.…”