Repair of the musculocutaneous nerve using the vagus nerve as donor by helicoid end-to-side technique: an experimental study in rats.

Although several donor nerves can be chosen to repair avulsed brachial plexus nerve injury, available nerves are still limited. The purpose of this study is to validate whether the vagus nerve (VN) can be used as a donor. Eighteen Sprague-Dawley male rats were divided into three groups (n = 6). The right musculocutaneous nerve (McN) was transected with differing subsequent repair. (1) HS-VN group: a saphenous nerve (SN) graft-end was helicoidally wrapped round the VN side (epi-and perineurium was opened) with a 30 ° angle, distal SN end was coapted to the McN with end-to-end repair. (2) EE-PN group: a SN was interpositionally grafted between the transected phrenic nerve (PN) and the McN by end-to-end coaptation. (3) Sham control group: McN was transected and not repaired and postoperative vital signs were checked daily. At three months, electrophysiology, tetanic force, wet biceps muscle weight, and histology were evaluated. Every tested mean value in HS-VN group was significantly greater than the EE-PN or the sham control groups (p < 0.05 or p < 0.005). The mean recovery ratio of regenerated nerve fibers was 96% and, in HS-VN group, the mean recovery ratio of CMAP was 79%. No vital signs changed in any group. There was no statistical difference (p > 0.5) between the mean VN nerve-fiber numbers of the segments proximal (2237 ± 134) and distal (2150 ± 156) to the VN graft-attachment site. Histological analysis revealed no axon injury or intraneural scarring at any point along the VN. This study demonstrated that VN is a practical and reliable donor nerve for end-to-side nerve transfer. © 2017 Wiley Periodicals, Inc.

Effect of vagal autotransplantation on quantitative [3H]-vesamicol binding image in rats with unilateral lesions of nucleus baslis magnocellularis.

It is considered that nodosal ganglion grafting improves learning and memory disorder in nucleus basalis magnocellularis lesioned rats, and that [3H]-vesamicol is one of the mapping agents for presynaptic cholinergic neurons. Quantitative autoradiography was performed using high sensitive imaging plate system to evaluate the effect of neurotransplantation on [3H]-vesamicol binding. The affected-side to unaffected-side ratio of [3H]-vesamicol in the nucleus basalis magnocellularis lesioned group was significantly lower than that in the sham-operated group at 1, 2 and 4weeks (P<0.01). In the transplanted group, the ratio was significantly higher than that in the untreated group at 4weeks (P<0.05). [3H]-vesamicol binding is one of the most sensitive indicators of nucleus basalis magnocellularis lesions and the effect of the nodosal ganglion grafting.

[Study on the anti-dementia therapies for rats with a unilateral basal forebrain lesion--serial changes of the cholinergic markers' activities and event-related potentials after the administration of bifemelane hydrochloride or autotransplantation of the vagal nodosal ganglion].

Using rats with a unilateral lesion in the nucleus basalis magnocellularis (NBM), we examined electrophysiologically the therapeutic effects of bifemelane (BIF) and autotransplantation of the vagal nodosal ganglion (X) on the event-related potential (P300) serially for 4 weeks, and also neurochemically their effects on cholinergic markers--the specific binding of 3H-QNB (quinuclidinyl benzilate) on muscarinic acetyl-choline receptor (mAChR) and the activities of acetylcholinesterase (AChE) and choline acetyltransferase (CAT). The latency of P300 was continuously delayed and its amplitude remained low voltage until 4 weeks in the NBM-lesioned rats (No-Tx group). Whereas the latency and amplitude returned to normal after 2-3 weeks in the rats given daily intraperitoneal injection of 15 mg/kg BIF (BIF group) and autotransplanted ones (X group). The cortical CAT and AChE levels on the lesion side did not recover until 4 weeks in No-Tx group, but the CAT levels recovered after 3 weeks in both BIF and X group; the AChE levels, after 1 week in BIF group and after 3 weeks in X group. The cortical mAChR on the lesion side was within or more than normal range in all rats. These results might indicate as follows: 1) Compensatory postsynaptic process such as cortical mAChR increase and AChE decrease occurred after acute cholinergic depletion. 2) Administration of BIF and X autotransplantation recovered cortical CAT and AChE levels and normalized cholinergic neuronal activity of P300.

Transplantation of peripheral cholinergic neurons into Alzheimer model rat brain.

The effect of transplantation of peripheral cholinergic neurons was examined in rats with a lesion of the nucleus basalis Meynert (NBM). The rats with an NBM lesion showed abnormal increase of spontaneous activity, disturbance of memory retention, and disturbance of learning acquisition. In contrast, the rats which had received transplantation of cholinergic neurons into the cerebral cortex displayed amelioration of abnormal behavior produced by the destruction of the NBM. Morphological study (acetylcholinesterase) clearly showed survival of many transplanted cholinergic cells. The present study suggests that autotransplantation of peripheral cholinergic cells may be a possible therapy for Alzheimer's disease.

Motor innervation of striated oesophageal muscle. Part 2. Characteristics of the oesophagomotor fibres in the rat studied by implanting the vagus nerve into a skeletal muscle.

In 12 rats the right vagus nerve distal to its recurrent laryngeal branch was implanted into the inferior segment of the denervated sternohyoid muscle. One month after implantation the first signs of neuromuscular transmission at the vagal motor endings could be recorded. Two months after implantation the reinnervated muscles showed vigorous contractions on electrical stimulation of the vagus nerve. During the performance of propulsive waves of the oesophagus the implanted vagus nerve caused clonic to tetanic contractions of the sternohyoid muscle, thus proving the oesophagomotor genesis of the reinnervating nerve fibres. In addition, the vagus-innervated motor end-plates were shown to exhibit the same ultrastructural peculiarities as the original neuromuscular junctions of the oesophagus. In sections stained for cholinesterase it could be demonstrated that the oesophagomotor fibres had preferentially reinnervated the denervated motor end-plates. In many instances the subneural apparatus was not completely covered by the vagal axon terminals. Newly formed, ectopic vagal motor endings were few in number and confined to muscle fibres immediately adjacent to the site of nerve-implantation. Six months after implantation some of the vagal motor endings showed signs of degeneration. As in the oesophagus, the reinnervating oesophagomotor fibres proved to be unmyelinated, sometimes forming a plexus-like intramuscular network before terminating at motor end-plates. Myelinated vagal nerve fibres were also observed running between the skeletal muscle fibres, but they did not establish any demonstrable form of neuromuscular contacts. It was concluded that, in the rat, the myelinated fibres of the oesophageal nerves are afferent, whereas the oesophagomotor fibres, although supplying striated muscle, are unmyelinated.

Laryngeal transplantation: current status 1974.

There are four major areas of concern that must be examined before human laryngeal transplantation can be considered feasible in clinical practice. These are: 1. surgical mechanics of revascularization; 2. reinnervation; 3. prevention of host rejection; and 4. justification. Of these criteria, the first two habe been met sucessfully at present. Safe suppression of rejection without increased risk of cancer recurrence remains to be achieved. Until this third criterion is satisfied, one is probably not justified to make further attempts at laryngeal transplantation in humans.