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Authors: Tomatsuri, Masaki | Okajima, Seiichiro | Ide, Chizuka

Article Type: Research Article

Abstract: Sprouting from crush-injured rat sciatic nerves was studied by electron microscopy to clarify how regenerating sprouts are generated at the node of Ranvier and extended distally in the injured nerves. Three hours after injury, sprouting had already begun in a few nodes: part of the dense submembranous undercoat had disappeared from the nodal axolemma, and the axolemma was slightly evaginated where the undercoat was avoided. The sprout contained clear vesicles of about 50 nm in diameter in an amorphous axoplasm. In addition, vacuoles measuring 100–200 nm in diameter and multivesicular bodies were commonly found within or near these early sprouts. …Six to 12 h after injury, nodes of Ranvier with sprouts increased in number in the region 1–1.5 mm proximal to the lesion. Sprouts grew toward the overlying Schwann cell basal lamina, and extended through the space between the basal lamina and Schwann cell plasmalemma (or myelin sheath). In the stem region continuous with the parent axon, regenerating sprouts displayed prominent neurofilaments, which were randomly arranged at 1 day post-injury, but oriented longitudinally by 5 days post-injury. Show more

Keywords: Sprout formation, Node of Ranvier, Subaxolemmal undercoat, Peripheral nerve regeneration, Crushed by ligation, Rat sciatic nerve

DOI: 10.3233/RNN-1993-5403

Citation: Restorative Neurology and Neuroscience, vol. 5, no. 4, pp. 275-282, 1993

Authors: Thanos, Panayotis K. | Okajima, Seiichiro | Tiangco, David A. | Terzis, Julia K.

Article Type: Research Article

Abstract: Among the pathological sequelae of facial paralysis is a paralytic eye. Apart from the psychological and aesthetic deficits, facial paralysis if left untreated can lead to dryness, ulceration and eventual blindness. Although numerous restorative microsurgical approaches have been introduced to address the sequelae of this problem, complete restoration of function to denervated facial muscles remains elusive. Utilizing the rat model of facial paralysis the present research has as an objective to examine a dual treatment approach. Specifically, this study combined the current microsurgical treatment of the cross-facial nerve graft with local administration of insulin-like growth factor I (IGF-I). The efficacy …of this combined approach (cross-facial nerve graft + IGF-I) was assessed in the following ways: (a) behavior measurement of the blink response and (b) histomorphometry light and electron microscopy of the entire nerve graft. These data will help provide insight into the restoration of facial muscle function after trauma and assist in the future development of more potent treatment strategies. 7he local adnünistration of IGF-I (50 µg/ml) to the cross-facial nerve graft was found to restore the blink response faster and to strengthen the degree of eye closure. Light microscopy examination revealed that IGF-I significantly enhanced axonal regeneration within a nerve graft (a 22% increase in the mean number of axons), and increased the mean nerve fiber diameter and myelin thickness. Electron microscopy assessment of the nerve grafts demonstrated that the IGF-I treated grafts possessed a greater density of microtubules, which were evenly distributed within the axoplasm. Show more

Keywords: blink reflex, axon, myelin, osmotic pump, neurotrophic, reinnervation

Citation: Restorative Neurology and Neuroscience, vol. 15, no. 1, pp. 57-71, 1999