Experimental study of vascularized nerve graft: Evaluation of nerve regeneration using choline acetyltransferase activity

Abstract

A comparative study of nerve regeneration was performed on vascularized nerve graft (VNG) and free nerve graft (FNG) in Fischer strain rats. A segment of the sciatic nerve with vascular pedicle of the femoral artery and vein was harvested from syngeneic donor rat for the VNG group and the sciatic nerve in the same length without vascular pedicle was harvested for the FNG group. They were transplanted to a nerve defect in the sciatic nerve of syngeneic recipient rats. At 2, 4, 6, 8, 12, 16, and 24 weeks after operation, the sciatic nerves were biopsied and processed for evaluation of choline acetyltransferase (CAT) activity, histological studies, and measurement of wet weight of the muscle innervated by the sciatic nerve. Electrophysiological evaluation of the grafted nerve was also performed before sacrifice. The average CAT activity in the distal to the distal suture site was 383 cpm in VNG and 361 cpm in FNG at 2 weeks; 6,189 cpm in VNG and 2,264 cpm in FNG at 4 weeks; and 11,299 cpm in VNG and 9,424 cpm in FNG at 6 weeks postoperatively. The value of the VNG group was statistically higher than that of the FNG group at 4 weeks postoperatively. Electrophysiological and histological findings also suggested that nerve regeneration in the VNG group was superior to that in the FNG group during the same period. However, there was no significant difference between the two groups after 6 weeks postoperatively in any of the evaluations. The CAT measurement was useful in the experiments, because it was highly sensitive and reproducible.

Vascularized nerve grafts: an experimental study

“…[7][8][9][10][11] In our study the functional recovery was significantly better in the VNG than in NNG group in early assessments; on the contrary, in long-term assessments the difference of the regeneration was almost 5%. A significant increase in vessels and regenerated axons was observed in VNG after 30 days; on the other hand, although after 90 days the mean numerical values of axonal counting and morphometric nerve study were slightly better in the VNG, the differences between the two grafted groups were not statistically significant (p > 0,05).…”

“…Other histomorphological and morphometric studies [5][6][7] showed the morphologically optimal regeneration using VNG because of the immediate restoration of the circulation. On the contrary, Iwai et al 8 , found a better regeneration in the VNG than in NNG group at four weeks postoperatively, but they did not observe significant differences between the two groups six weeks postoperatively. We have observed greater axon diameter, with greater thickness of the myelin sheath and better epineurial and perineurial organization in the VNG after 30 and 90 days.…”

Vascularized versus Nonvascularized Island Median Nerve Grafts in the Facial Nerve Regeneration and Functional Recovery of Rats for Facial Nerve Reconstruction Study

“…Ã p < 0.05. effective vascularized nerve grafting over a period of 1 to 24 weeks using nerves such as sciatic nerve. [6][7][8] For elucidating the efficacy of vascularized nerve grafting over an extended period, this study performed a histological and physiological evaluations over a period of 30 weeks, which was much longer than the periods investigated in previous studies. Using the vascularized median nerve model, this study successfully showed that vascularized autologous nerve grafts provided better outcome in several nerve-regeneration parameters than in nonvascularized grafts for repairing facial nerve deficits.…”

“…5 However, the histological and physiological basis of the therapeutic efficacy of the vascularized autologous nerve graft in facial nerve regeneration remains poorly understood, because in part no established rat model with vascularized autologous nerve grafts for facial nerve regeneration is available. Although rat experimental models having sciatic and femoral nerve defects have been well used by many researchers for vascularized nerve studies, [6][7][8] no facial nerve reconstruction model with a vascularized nerve is developed because of its complicated anatomy.…”

An experimental study to determine and correlate choline acetyltransferase assay with functional muscle testing after nerve injury

“…17 Quantification of ChAT has been reported as a way of determining not only motor neuron function, but also possibly assisting in the differentiation between motor and sensory fibers as well as continuity of the nerve root. 1,11 The potential of using ChAT quantification for clinical use has been reported in the last 2 decades. 3,4 Hattori et al [7][8][9] reported that the level of ChAT activity could be used as a reliable indication of motor fascicles, based on a few clinical cases with intraoperative ChAT assays.…”