Effect Of Puerarin On Survival Of Ischemic Random Skin Flap In Rats And The Underlying Mechanism

Background: Random flap transplantation is a common method of wound repair in orthopedics.Distal necrosis of random skin flap is one of the common problems in clinical practice,mainly due to the lack of axial vessels.When the length to width ratio of random flaps is greater than 1.5-2:1,partial or even total necrosis often occurs at the distal end due to insufficient blood supply.Puerarin can inhibit local inflammation,reduce tissue ischemia reperfusion injury,resist oxidative stress,improve local microcirculation,promote tissue angiogenesis.The aim of this study was to investigate the effect of puerarin on the survival of ischemic random skin flap in rats and its mechanism..Methods: Thirty-six healthy male SD rats with body weight ranging from280-320 g were randomly divided into three groups: low-dose group(puerarin dose set at 50mg/kg),high-dose group(100mg/kg)and normal saline control group(normal saline with the same volume),with 12 rats in each group.A 3cm×9cm skin flap was designed in the middle of the back of each rat using the modified Mc Farlane skin flap model,and the survival of the skin flap was observed after the operation.Blood samples were collected 7 days after surgery.The flap survival area and survival rate were recorded and calculated.Hematoxylin and Eosin(HE)staining was used to observe neutrophil infiltration and microangiogenesis in the skin flap.Western Blot(WB)detects inflammatory factors such as Tumor necrosis factor-α(TNF-α)and Interleukin-6(interleukin-6).IL-6)and the expression of Vascular endothelial growth factor(VEGF).Real-time quantitative PCR(RT-q PCR)was used to detect m RNA expressions of VEGF,IL-6 and TNF-α in rat skin flaps.Malondialdehyde(MDA)content and Superoxide dismutase(SOD)activity were measured to evaluate oxidative stress.The levels of VEGF,TNF-α and IL-6 in serum were detected by Enzyme linked immunosorbent assay(ELISA),while C-Reactive protein in blood was detected by automatic biochemical analyzer.CRP)levels.Results: On the 7th day after operation,the survival rate of the flaps in the high-dose group was significantly higher than that in the low-dose group,and the survival rate of the flaps in the low-dose group was significantly higher than that in the control group.The number of new microvessels in the low-dose and high-dose groups was significantly higher than that in the control group,and the number of new microvessels in the high-dose group was the largest.A large number of neutrophils infiltrated in each group,with the most obvious infiltration in the control group,the second in the low-dose group,and the least in the high-dose group.Compared with the control group,puerarin group,especially the high-dose group,showed higher expression of VEGF,VEGFm RNA,SOD activity and serum content of VEGF in the skin flap than the control group.The contents of IL-6,TNF-α and MDA in skin flap and the levels of CRP,IL-6 and TNF-α in serum were significantly decreased in puerarin group,especially in high-dose group.Conclusion: Puerarin can promote the survival of ischemic random skin flap in SD rats,and the effect of high dose group is more obvious than that of low dose group.Puerarin can promote the survival of rat skin flap by promoting microangiogenesis,improving local microcirculation,inhibiting inflammatory response,reducing oxidative stress response,and alleviating ischemia reperfusion injury.