Objective:To observe the influence of low intensity ultrasound on expression of hormone receptor in experimental mammary dysplasia. Methods:Totally 24 female New Zealand rabbits were divided randomly into 3 groups :A

B

C

n =8. Group A(control group)received no treatment;group B(sham treatment group)and group C(treatment group)were modeled;after modeling

group B received sham treatment and group C received low-intensity ultrasound. The height of nipple was observed and measured at each time(before modeling

after modeling

15 d after treatment). Pathological changes were observed by HE staining;the expressions of hormone receptor were detected by immunohistochemistry(ERα

ERβ and PR). Results:(1)After modeling

the height of nipple increased obviously in group B and C(P=0.000

P=0.000);the height of nipple decreased in group C after treatment(P=0.000).(2)Compared with those of group A

the number of breast lobular

alveolar and ductal epithelium layer increased obviously in group B(P=0.000

P=0.000

P=0.000);compared with those of group B

the number of breast lobular

alveolar and ductal epithelium layer decreased obviously in group C after treatment(P=0.000

P=0.000

P=0.000).(3)The expressions of ERα and PR in group B were higher than those in group A(P=0.006

P=0.000);the expression of ERα and PR in group C decreased after treatment(P=0.039

P=0.000). There was no statistical significance in the expression of ERβ between the three groups(F=0.013

P=0.987). Conclusion:Regulating the expression of hormone receptor perhaps an important mechanism in low intensity ultrasonic treatment of mammary dysplasia.