Experimental study on the effect of low-dose irradiation X-ray irradiation on ischemic flap survival / 中华显微外科杂志

ABSTRACT

Objective To explore the effects of low-dose X-ray irradiation effects on ischemic flap survival and its possible mechanism.Methods From June, 2014 to December, 2014, 80 SD rats were include in the study, the rats were randomly divided into 2 groups the experimental group A and control group B.There were 40 rats in each group.The ischemic flaps with the size of 9 cm × 3 cm were designed on the back of the rats.The pedicle of the flaps was near to the tail.A sterile biological isolating membrane was placed under the flap to block the blood supply between muscular layer and flaps.The flaps were intermittently sutured into their original position.The group A was immediately received single and local irradiation of 0.2 Gy after surgery, The group B was not treated.On days 1 to 14 after operation,general observation,HE staining and the western blot of the flaps were performed to calculate the survival vate of the flaps, observe neovascularization and determin the content of VEGF and MMP-9, respectively.Results On the third, seventh and fourteenth days, survival rates of the flaps in the experimental group [(66.46 ± 4.37)％, (44.30 ± 3.86)％, (32.20 ± 4.22)％, respectively] were higher than the control group [(43.15 ± 5.03)％, (27.71 ± 3.20)％, (16.40 ± 5.34)％, respectively] after inspection, there were statistically significant differences between these indices (P ＜ 0.01), HE staining of the flaps in the experimental group were seen in the fibroblast infiltration and neovascularization were higher than that of control group, and experimental group within the lumen of blood vessels were arranged in order, the groups were visible tissue edema obviously control, neovascularization in small numbers, the lumen was irregular.On the third and seventh days, MVD rates of the flaps in the experimental group (85.54 ± 6.12, 44.32 ± 3.56, respectively) were higher than the control group (49.35 ± 4.75,18.75 ± 2.89,respectively) after inspection, there were statistically significant differences between these indices (P ＜ 0.01).VEGF and MMP-9 protein content in the flap for the seventh day in the experimental group were significantly higher than that of the control group.Conclusion Low-dose X-ray irradiation can promote the survival rate of ischemic flap, the mechanism may be related to the expression of VEGF and MMP-9 increased and promoted angiogenesis of the flaps after low-dose X-ray irradiation.