TY - JOUR AU - Kerns, James M.; Walter, James S.; Patetta, Michael J.; Sood, Anshum; Hussain, Awais K.; Chung, Joyce J.; Deshpande, Abhishek; DesLaurier, Justin T.; Dieter, Raymond A.; Siemionow, Maria; Seiler, Figen A.; Amirouche, Farid M.L.; Gonzalez, Mark H. TI - Histological Assessment of Wallerian Degeneration of the Rat Tibial Nerve Following Crush and Transection Injuries SN - 0743-684X SN - 1098-8947 PY - 2020 JO - J Reconstr Microsurg JF - Journal of Reconstructive Microsurgery LA - EN VL - 37 IS - 05 SP - 391 EP - 404 DA - 2020/09/24 KW - Wallerian degeneration KW - ultrastructure KW - peripheral nerve KW - rat sciatic nerve repair KW - axons AB - Background Wallerian degeneration (WD) following peripheral nerve injury (PNI) is an area of growing focus for pharmacological developments. Clinically, WD presents challenges in achieving full functional recovery following PNI, as prolonged denervation of distal tissues for an extended period of time can irreversibly destabilize sensory and motor targets with secondary tissue atrophy. Our objective is to improve upon histological assessments of WD.Methods Conventional methods utilize a qualitative system simply describing the presence or absence of WD in nerve fibers. We propose a three-category assessment that allows more quantification: A fibers appear normal, B fibers have moderate WD (altered axoplasm), and C fibers have extensive WD (myelin figures). Analysis was by light microscopy (LM) on semithin sections stained with toluidine blue in three rat tibial nerve lesion models (crush, partial transection, and complete transection) at 5 days postop and 5 mm distal to the injury site. The LM criteria were verified at the ultrastructural level. This early outcome measure was compared with the loss of extensor postural thrust and the absence of muscle atrophy.Results The results showed good to excellent internal consistency among counters, demonstrating a significant difference between the crush and transection lesion models. A significant decrease in fiber density in the injured nerves due to inflammation/edema was observed. The growth cones of regenerating axons were evident in the crush lesion group.Conclusion The ABC method of histological assessment is a consistent and reliable method that will be useful to quantify the effects of different interventions on the WD process. PB - Thieme Medical Publishers, Inc. DO - 10.1055/s-0040-1716870 UR - http://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-0040-1716870 ER -