Effects of continuous elastic outside distraction on expression of basic fibroblast growth factor and transforming growth factor-beta 1 in nipple of female minipig model

Abstract

Objective To observe the effect of continuous elastic outside distraction on the expression of basic fibroblast growth factor (bFGF) and transforming growth factor-beta 1 (TGF-β1) in the female porcine nipples,and to further investigate the mechanism of continuous elastic outside distraction stimulation on the proliferation of supporting tissue in nipples.Methods Three female minipigs were employed,each of them had 12 nipples.Four nipples of each minipig were used as control group,while the other eight nipples were continuously distracted with prefabricated instruments.One nipple without distraction and two distracted nipples of each minipig were excised at 2,4,8,and 12 weeks after operation under general anesthesia respectively.The excised nipples were prepared for immunohistochemical staining to observe the expression of bFGF and TGF-β1.Image analysis software was employed for quantitative analysis.Results bFGF and TGF-β1 expression of control groups was weaker than those of the distracted groups at any time (P＜0.01).The expression of bFGF increased gradually after tracted and reached the peak at 4 weeks.There was significant difference (P＜0.05) in the expression of bFGF between 4 weeks and 12 weeks groups.The expression of TGF-β1 was increased to the peak after 2 weeks.The expression of TGF-β1 between 8 weeks and 12 weeks groups and 2 weeks group had statistical significance (P＜0.05).The expression of bFGF and TGF-β1 had a positive correlation during the traction.Conclusions Continuous elastic outside distraction can promote female minipig nipple to synthesis and secretion of b-FGF and TGF-β1. Key words: Elastic distraction; Inverted nipple; Female minipig; Basic fibroblast growth factor (bFGF) ; Transforming growth factor-beta 1 (TGF-β1)