Effect of γ-ray on wound healing of skin defect in mice and its mechanism

Objective To observe the effect of γ-ray on wound healing of skin defect in mice and to explore its mechanism. Methods A total of 60 healthy male C57 BL /6 mice were randomly divided into the control group( n = 30) and observation group( n = 30). Those C57 BL /6 mice in the observation group were irradiated 5 minutes with a single dose of60Co-γ-ray( 6 Gy). After the mice were anesthetized and sterilized,1 cm × 1 cm wound to fascia on the back was made,the wound was covered by the Tegaderm TM paster,and we cleaned the wound every other day. Those mice in the control group were not irradiated,and the other treatments were the same as that in the observation group. The wound residual area was measured using Image analysis system( Image Proplusv 1. 5) in the two groups on day 3( T0),7( T1) and 14( T2)after damage,and the number of new capillaries and fibroblasts in wound were observed at the same time. The mRNA expression levels of vascular endothelial growth factor( VEGF),basic fibroblast growth factor-2( FGF-2),platelet-derived growth factor( PDGF) and transforming growth factor-β( TGF-β) in the dermal defects were detected by Real-time PCR.Results With the extension of time,the residual wound areas gradually reduced in the two groups,and the newborn capillaries and fibroblasts in wound first increased and then decreased. The residual wound areas were larger in the observation group than those of the control group at different time points. The number of new capillaries at T0,and the number of fibroblasts at T0 and T1in observation group were lower than those of the control group at the same time points( all P 0. 05).The mRNA expression levels of VEGF,PDGF and TGF-β at T0 and T1and the FGF-2 mRNA expression level at each time point in the observation group were lower than those of the control group at the same time points( all P 0. 05). Conclusion The γ-ray can delay the wound healing of skin defect in mice,and it may be related with the decreased expression of angiogenesis factor and fibroblast factor and inhibition of the angiogenesis and granulation tissue formation.