Protective effect of vitamin D on radiation-induced lung injury: Experimental evidence

Background: Vitamin D, especially its most ac ve metabolite 1,25‐dihydroxyvitamin D3(Vit D) is essen al in regula ng a wide variety of biologic processes, such as regula ng mesangial cell ac va on. The objec ve of this study was to assess the histopathological changes of effec veness of Vit D as a protec ve agent against radia on induced lung injury. Materials and Methods: Eighteen Wistar rats were divided into three groups: control group (group 1:4 rats), irradia on alone group (group 2:7 rats) and irradia on+vit D (group 3:7 rats). Rats in group 2 and 3 were exposed to 20 Gy radia ons to the right lung in a Co radiotherapy machine under general anesthesia. Addi onally, rats in group 3 received Vit D at a single dose of 0.2 mcg injected IM 2 hours before exposure to irradia on. Rats were sacrificed and lungs were dissected fi y days a er post‐irradia on. Myofibroblasts and vitamin D3 receptors (VDR) in extracted lungs were stained by immunohistochemistry using alpha‐smooth muscle ac n (SMA) and VDR an bodies. Blinded histological evalua on was performed to assess lung injury. Lung injury was assessed by the acute lung injury score and myofibroblas c differen a on score. Results: Acute lung injury scores and myofibroblas c differen a on scores were significantly lower in the radia on+vit D group compared to irradia on alone group (p=0.001 and p=0.001, respec vely). Conclusion: This study indicates that administra on of vit D plays a protec ve role against acute lung injury through blocking myofibroblas c differen a on.