Objective: To study the molecular mechanism of the stimulatory effect of low dose radiation (LDR) on T cell activation.
Methods: Thymocytes from Kunming mice exposed to whole-body irradiation (WBI) with different doses of X-rays were analyzed for the changes in signal molecules of the phospholipase C-phosphatidylinositol biphosphate (PLC-IP2) and G protein-adenylate cyclase (AC) pathways.
Results: It was found that [Ca2+]i increased in response to doses within 0. 2 Gy which was most marked after 0. 075 Gy and the increase was accentuated in the presence of Con A. The changes in CD3 and calcineurin (CN) expression of the thymocytes followed the same pattern as the alterations in [Ca2+]i after LDR. The expression of alpha, beta1 and beta2 isoforms of protein kinase C (PKC) was all up-regulated after 0.075 Gy with the increase in PKC-beta1 expression being most marked. The cAMP/cGMP ratio and PKA activity of the thymocytes was lowered after low dose radiation and increased after doses above 0. 5 Gy in a dose-dependent manner, thus giving rise to J-shaped dose-response curves. The Ca antagonist TMB-8 and cAMP stimulant cholera toxin suppressed the augmented thymocyte proliferation induced by LDR.
Conclusion: Data presented in the present paper suggest that activation of the PLC-PIP2 signal pathway and suppression of the AC-cAMP signal pathway are involved in the stimulation of the thymocytes following WBI with low dose X-rays.
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Invest Radiol
January 2025
From the Departments of Radiology (J.F.H., S.Y.C., J.-P.G., J.S., P.N., S.B.R., T.M.G.), Biomedical Engineering (S.B.R., T.M.G.), Medical Physics (S.Y.C., S.B.R., T.M.G.), Medicine (S.B.R.), and Emergency Medicine (S.B.R.), University of Wisconsin-Madison, WI; and Department of Diagnostic and Interventional Radiology (J.F.H., J.-P.G.), University Hospital Würzburg, Würzburg, Germany.
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China Tobacco Sichuan Industrial Co., Ltd., Chengdu, China; Harmful Components and Tar Reduction in Cigarette Key Laboratory of Sichuan Province, Chengdu, China; Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.
In recent years, the health challenges linked to frailty in the elderly, particularly those worsened by cigarette smoke, have become more pronounced. However, quantitative studies examining the impact of smoking dosage on frailty in this population remain limited. To address this gap, we developed a model using smoke-exposed elderly mice.
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