Abstract: Objective：To observe the expression situation of the partial endocardial mechano growth factor mRNA in the recovery process of the injured female WISTAR rats′ urethra sphincter who have childless show whether the machinery growth factor does participate in muscle cell regeneration and recovery process of Wistar rats′ urethra sphincter. Methods：Divide 60 female Wistar rats who have childless into two groups stochastically. In the experimental group，there are 30 of them whose urethra sphincters are injured like birth injury by obstetrician′s instruments. And then execute them and take out the urethra on the 1sｔ，４ｔｈ，7th，10th and14th day respectively（6/d）. There are 30 as the blank control group，Execute them and take out the urethra，too. On all specimens，the comparative quantitation PCR of internal reference should be carried on，then examine the expression situation of the partial mechano growth factor. Results：In the blank control group，the partial endocardial machinery growth factor mRNA only has extremely little expression quantity，but the expression of it increases significantly on the 1st day after the urethra sphincter was injured，and increases gradually，then reaches the peak on the 7th day,and then drops gradually. However，the expression quantity on the 14th day is still higher than that in the blank control group（P＜0.05）. Conclusions：The expression quantity of the partial endocardial machinery growth factor mRNA increases in the recovery process of the injured female Wistar rats′ urethra sphincter who have childless，and the expression quantity is different in different injured time. It shows that the machinery growth factor does participate in muscle cell regeneration and recovery process of Wistar rats′ urethra sphincter.

Key words: Urinary incontinence, stress, Insulin-like growth factor I, Mechano growth factor, Urethral sphincter