Vasa recta were ligated 30min after VS infusion ended in group A( n =4), and 2h after VS infusion ended in group B( n =4), they were ligated without VS infusion in control group ( n =2).

• A组 (n =4) ,VS应用终止后 30min结扎直动脉 ; B组(n =4) ,VS应用终止后 2h结扎直动脉 ;