The effect of early external X-ray radiation on arterial restenosis post percutaneous transluminal angioplasty

Arterial restenosis after percutaneous transluminal angioplasty (PTA) significantly reduces its therapeutic efficacy in treating lower extremity atherosclerotic occlusive diseases (LEAOD). Early external X-ray external radiation has demonstrated positive effects on restenosis; however, effective dosing and the mechanism(s) underlying its efficacy remain unknown. This study explored the effect of early external X-ray radiation on preventing post-PTA restenosis in an iliac intimal injury model.

Early external X-ray radiation at 6-24 Gy doses effectively restrained VSMC hyperplasia post-PTA, likely through inducing VSMC apoptosis via mitochondrial Cyt C release. However, this technique did not significantly affect the integrity of the vascular endothelium. Therefore, early external X-ray radiation shows promise in preventing post-PTA restenosis.

Twenty rabbits underwent iliac intimal injury via PTA and received five different radiation doses: 0 Gy (n = 4), 3 Gy (n = 4), 6 Gy (n = 4), 9 Gy (n = 4), and 12 Gy (n = 4). Four rabbits were used as controls. All subjects were fed a high-fat diet prior to PTA and for an additional four-week period post-PTA and then sacrificed for immunohistochemical and Western blotting analysis.

Arterial stenosis was significantly improved post-PTA. Alpha smooth muscle actin (α-SMA) expression in the 0 Gy to 9 Gy groups was significantly increased post-PTA. Cytochrome C (Cyt C) expression was significantly increased post-PTA and was positively correlated with radiation intensity. Proliferating cell nuclear antigen (PCNA) expression was significantly increased post-PTA with the 0 Gy group showing significantly higher expression than the 3 Gy group. No significant differences were found in CD34 levels between the groups. Conclusions: Early external X-ray radiation at 6-24 Gy doses effectively restrained VSMC hyperplasia post-PTA, likely through inducing VSMC apoptosis via mitochondrial Cyt C release. However, this technique did not significantly affect the integrity of the vascular endothelium. Therefore, early external X-ray radiation shows promise in preventing post-PTA restenosis.