Abstract: Objective To explore the effects and mechanism of ultra-short wave(USW) for prevention and treatment of vascular crisis after rat tail replantation. Methods The animal experiments were carried out from October 2009 to June 2010. Eighty 3-month old female Sprague Dawley rats (weighing 232.8-289.6 g) were randomly divided into ifve groups. In each group, based on the caudal vein and the coccyx was retained, the tail was cut off. The tail artery was ligation in Blank group. The tail artery were anastomosed in Control group, Papaverine group, USW high dose group and USW low dose group group to establish the tail replantation model. After surgery, the rats of the Papaverine group were immediately given papaverine hydrochloride injection. The rats of the USW high dose group and the USW low dose group were immediately given the local USW treatment at anastomotic site within postoperative twenty minutes, once a day thereafter, for 5 days at the dosage of three tranche and 50 mA for 20 min(high dose group) and two tranche and 28 mA for 20 min(low dose group). The survival of the rat tails was observed after the tail replantation for 10 days. The difference between proximal and distal anastomosis site tail skin temperature were measured before and after the replantation; the change between postoperative and preoperative temperature difference was calculated. From the inner canthus before the replantation and from the tip of the tail at postoperative 8th hour, rats were collected blood plasma specimens and measured contents of endothelin. Results The survival rates of the rat tails were 0%(0/14) and 44%(29/66)in the tails cutting off group (Blank group) and the tail replantation group (Control group, Papaverine group, USW high dose group, USW low dose group) respectively, showing signiifcant difference among two groups (χ2=9.649, P=0.002). The survival rates of the rat tails were 0%(0/14), 36.4%(8/22), 57.1%(8/14), 22.2%(4/18), 75.0%(9/12) in groups Blank, Control, Papaverine, USW high dose and USW low dose respectively, showing signiifcant over all differences among 5 groups (χ2=19.935, P=0.001). The differences showed signiifcant among the tail replantation groups (Control, Papaverine, USW high dose, USW low dose):(χ2=9.650, P=0.022). Pairwise comparisons among the tail replantation groups: USW low dose group>Control, USW low dose group>USW high dose group, Papaverine group>USW high dose group, the differences were statistically significant (P<0.05), but significant difference wasn’t found between the other groups (P>0.05). Before the replantation, there were no significant difference in tail skin temperature difference between the groups (P>0.05). At 8th hour, 5th, 6th and 7th day after the replantation, significant overall difference was found in the change of the skin temperature difference between the groups (P<0.05). The pairwise comparison showed signiifcant differences after the replantation (P<0.05):Control group>USW high dose group at 8th hour. Papaverine group>USW high dose group at 5th day, groups Blank, Control and Papaverine>USW high dose group at 6th day, groups Control and Papaverine>groups Blank and USW low dose, and Control group>USW high dose group at 7th day, no significant difference was found between the other groups at the other time (P>0.05). Preoperative plasma ET content between the groups hadn’t signiifcant difference(P>0.05). The overall difference was statistical significant in the difference between preoperative and postoperative the ET content among groups (P<0.05):USW low dose group>Papaverine group>USW high dose group>Control group>Blank group, P=0.004. Signiifcant differences were found by pairwise comparison (P<0.05):groups Papaverine and USW lowe dose>groups Blank and Control, USW high dose group>Blank group. Remaining pairwise comparisons between the other groups had no statistical significance(P>0.05). Conclusion USW therapy, especially USW low-dose therapy, can reduce vascular crisis and improve the survival rate of replanted rat tails, after the postoperative 8th hour, 5th, 6th, 7th day, reduce skin temperature, improve blood supply, reduce endothelin at postoperative 8th hour, prevent vascular crisis. Rat tail replantation model in this experiment is feasible.

Key words: tail replantation, vascular crisis, ultra-short wave, endothlial cells, endothelin, skin difference in temperature