[Study of healing mechanism of acellular dermal matrix in the treatment of anal fistula].
OBJECTIVE
To evaluate the efficacy of acellular dermal matrix(ADM) in the closure of anal fistula in an experimental porcine model, and to explore its healing mechanism.


METHODS
The fistula-in-ano model was created and treated with ADM in the porcine model (n=14). Fistula specimens were obtained at hour 12, 24 and day 3, 7, 14, 28, 60 respectively with 2 pigs in each time point. Hematoxylin and eosin staining and immunohistochemical staining for the alpha smooth muscle actin (α-SMA) were performed.


RESULTS
At 12 hours after implantation, neutrophils and scattered cells with a fibroblastic appearance were present at the interface and began to infiltrate into the ADM. The cell density increased from hour 12 (218.2±58.2) to day 7(998.7±128.0) (P<0.01), and decreased from day 7 to day 28. Mature vessels and myofibroblasts stained with α-SMA were identified at the edge of ADM at day 7. The density of vessels (11.2±3.3 vs. 30.5±5.2, P<0.01) and myofibroblasts (3.8±0.8 vs. 6.8±0.4, P<0.01) increased from day 7 to day 14. Partially organized bundles of muscle were found at day 60.


CONCLUSIONS
ADM is a reasonable new option for the closure of anal fistula. The ability of ADM to become vascularized and remodeled by autologous cells may be advantageous for anal fistula healing and other chronic septic wound.
Department of General Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China.
Jia-gang
JG
Han
Zhen-jun
ZJ
Wang
Bao-cheng
BC
Zhao
Hui-min
HM
Xu
Yi
Y
Zheng
Xin-qing
XQ
Yang
D062088:Acellular Dermis; D000818:Animals; D004195:Disease Models, Animal; D005347:Fibroblasts; D012003:Rectal Fistula / Q000601:surgery*; D016038:Skin Transplantation; D017768:Skin, Artificial; D013552:Swine; D014945:Wound Healing