Background: Reinnervation of target tissues determines functional outcomes after nerve grafting, which is important in traumatic injury caused by accidents or consequences resulting from surgical removal of tumors. Previous studies documented the influences of nerve repair mainly based on nerve morphometry but rarely compared the final outcomes according to target reinnervation patterns by nerve fibers of different categories.
Methods: In a mouse model of nerve grafting, the authors analyzed the innervation indexes of different target tissues after transection-reimplantation on the sciatic nerve, which were defined as a parameter on the operated side normalized to that on the control side.
Results: Muscle reinnervation appeared to be the best compared with skin reinnervation (p < 0.0001) and sweat gland reinnervation (p < 0.0001) at postoperative month 3. The sudomotor reinnervation was relatively higher than the cutaneous reinnervation (p = 0.014). The abundance of trophin transcripts for brain-derived neurotrophic factor (BDNF), glial cell line–derived neurotrophic factor (GDNF), and neurotrophin 3 (NT3) was higher in plantar muscles on the operated side than those on the control side. In contrast, transcripts of BDNF, GDNF, nerve growth factor, and NT3 were all similar in the footpad skin between the operated and control sides.
Conclusions: The results suggested that, compared with the skin, muscles achieved the best reinnervation after nerve grafting, which was related to higher expression of BDNF, GDNF, and NT3 in muscles than in the skin.
From the Departments of Anatomy and Cell Biology, the Graduate Institute of Molecular Medicine, the Graduate Institute of Brain and Mind Science, College of Medicine, School of Medicine, the Departments of Surgery and Neurology, National Taiwan University, and the Department of Surgery, Cathay General Hospital.
Received for publication August 31, 2012; accepted November 19, 2012.
Disclosure: The authors have no financial interest to declare in relation to the content of this article.
Department of Neurology, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 10002, Taiwan, firstname.lastname@example.org
Institute of Molecular Medicine, National Taiwan University, 7 Chung-Shan South Road, Taipei 10002, Taiwan, email@example.com