[Effect of exogenous L-arginie on survival of extended dorsal perforator flaps in rats]

Objective: To investigate the effect of exogenous L-Arg on the survival of extended perforator flap in rats. Methods: Sixteen male Sprague Dawley rats were randomly divided into L-Arg group (n=8) and control group(n=8). The extended dorsal three-vascular territory perforator flaps were made in rats. L-Arg (400 mg·kg^-1·d^-1) was injected intraperitoneally in L-Arg group 1d before operation, immediately and 1-7 d after operation, while the same volume of saline was injected intraperitoneally in control group at the same time points. The appearance and distribution of blood vessels were observed, and the flap survival areas were measured 7d after operation. The tissue samples were harvested from choke zone Ⅱ for histological study and the expression of vascular endothelial growth factor (VEGF) was detected by immunohistochemistry and Western blot, respectively. Results: After 7d, the clearer vascular structure and more new vessels in choke zone Ⅱ were observed in L-Arg group. The survival rate of flap in L-Arg group was (88.42±4.19)%, which was significantly higher than that in control group[(76.52±5.37)%, t=3.707, P<0.01]. The microvessel density and caliber of choke zone Ⅱ in L-Arg group was (29.47±5.28)/mm² and(47.27±5.32)μm, which were significantly higher than those in control group (t=2.694 and 2.389, P<0.05 or P<0.01). The immunohistochemistry and Western blot showed that the expression of VEGF in choke zone Ⅱ of L-Arg group was significantly higher than that in control group (t=9.428 and -3.054,P<0.05 or P<0.01). Conclusion: Exogenous L-Arg can increase the survival rate of extended dorsal perforator skin flap through promoting vascularization and dilatation of vessels in choke zone Ⅱ in rats.