Objective:To observe hemodynamic effects of unilateral testicular torsion on the contralateral testis in immature rats

and compare the therapeutic effects of different treatments.Methods:The left testicular torsion model was established in rats of 3m old

and divided into normal control group

testicular torsion group

reposition group and orchectomy group.The value of peak systolic velocity(Vs)

value of end diastolic velocity(Vd)and resistive index(RI)of right testicular artery of pre-operation

8 h(2 h after reposition or orchectomy)

12 h

24 h

72 h and 1 w post-operation were measured by color Doppler in each group.Results:The blood supply of the right immature testes increased consistently after testicular torsion of the left side

and reached the peak value at 8h after the operation.The Vs of right testicular artery reduced significantly at 6 h compared with that at 2 h after reposition(P<0.01)

but still higher than that in control group or the testicular torsion group.The Vs of right testicular artery increasd significantly at 6 h compared with that at 2 h after orchectomy(P<0.01)

then decreased gradually

which was higher at 72 h after operation than that in control group or the reposition group

but lower than that in testicular torsion group.The Vs

Vd and RI were all higher in orchectomy group than those in reposition group at 1w after operation.Conclusion:The unilateral immature testicular torsion significantly induces increase of blood supply of contralateral testis in immature rats

and the increase is continuing in both the reposition group and orchectomy group.