The impact of X-rays on cardiac hydrometabolism and the regulatory role of AS-IV

Background: Radiation-induced cardiac injury has emerged as a significant pathological entity, with many studies focusing on the fibrotic changes in myocardial tissue. However, these do not offer solutions for the clinical prevention and treatment of radiation-induced heart disease. Regulating hydrometabolism presents a potential therapeutic target for the management of cardiovascular diseases. This research seeks to explore the impacts of irradiation on cardiac hydrometabolism and its regulatory mechanisms.

Methods: The impact of X-ray radiation on cardiac and cardiomyocyte hydrometabolism was studied through in vivo and in vitro experiments, examining the pharmacological effects and mechanisms of PX-478 and AS-IV interventions in cardiomyocytes.

Results: 28 days after direct chest irradiation with 20 Gy X-rays, C57BL/6 mice exhibited an increased heart wet-to-dry weight ratio, significant enlargement of cardiomyocyte cross-sectional area, and elevated protein expression of HIF-1α, AQP1, AQP4, Cx43, Caspase3, and Bax, with decreased expression of Bcl-2. Irradiation with 6 Gy X-rays induced edema and damage in AC16 and HL-1 cardiomyocytes at 24, 48, and 72 h, with increased expression of HIF-1α, AQP1, AQP4, and Cx43 proteins post-radiation. Inhibition of HIF-1α ameliorated edema and apoptosis in AC16 and HL-1 cardiomyocytes, reducing the expression of HIF-1α, AQP1, AQP4, and Cx43 proteins. AS-IV demonstrated strong binding affinity with HIF-1α, and successfully attenuated the expression levels of HIF-1α, AQP1, AQP4, and Cx43 proteins, alleviating edema, mitochondrial swelling, and apoptosis in AC16 and HL-1 cardiomyocytes. Furthermore, AS-IV improved cardiomyocyte edema by restoring the activity of Na/K-ATPase.

Conclusion: Aberrant activation of the HIF-1α/AQPs/Cx43 axis is a key mechanism in X-ray-induced cardiomyocyte edema and damage. AS-IV can ameliorate X-ray induced cardiac damage by regulating hydrometabolism.