title: [Low frequency ultrasound promotes lactation in lactating rats].
abstract: OBJECTIVE
  To investigate the effect of low-frequency ultrasound in promoting milk secretion in rats during lactation.
  
  
  METHODS
  Twenty-four lactating SD rats feeding 10 suckling rats each were randomly allocated into 3 groups, namely the control group (with sham irradiation), 5 min group (with ultrasonic irradiation of the breast for 5 min daily), and 10 min group (irradiation for 10 min daily). The mammary glands of the rats were consistently irradiated by low-frequency ultrasound (40 kHz, 0.26 W/cm(2)) for 7 days since the 2nd day after delivery. The milk yield, average body weight gain of the offspring, mammary gland index, serum prolactin (PRL) and breast histology were examined.
  
  
  RESULTS
  The milk yield, body weight gain of offspring, mammary gland index and serum PRL concentration in 10 min group were significantly greater than those in the control group and 5 min group (P<0.05). Compared with the other two groups, the 10 min group showed significantly increased acinar gland expansion and acinar number.
  
  
  CONCLUSIONS
  Low-frequency ultrasound can promote milk secretion in lactating rats, suggesting its potential as a new approach of physical therapy for promoting milk secretion.
authors.affiliation: College of Biomedical Engineering, Chongqing Medical University, Chongqing, China. baterwang@163.com
authors.forename: Qin
authors.initials: Q
authors.lastname: Wang
authors.forename: Hai
authors.initials: H
authors.lastname: Qiao
authors.forename: Jin
authors.initials: J
authors.lastname: Bai
mesh_terms: D000818:Animals; D005260:Female; D007774:Lactation; D051381:Rats; D017207:Rats, Sprague-Dawley; D014464:Ultrasonic Therapy