Length Of Sciatic Nerve Research Articles

Biodegradable polyester neuroprostheses promote the reconnection of separated peripheral nerve stubs

An 11mm length of sciatic nerve was removed from 10 anesthetized adult rats and replaced by a biodegradable polyester Vicryl™ mesh sleeve which was then injected with the basement membrane gel, Matrigel™. It was noted that leg sensation and movement were much improved after 30 to 45 days and upon sacrifice nerve reconnection was noted in all animals. Epoxy sections of the repaired nerves were compared with those of the excised segments by the use of a variation of the PAS reaction, the PATS reaction, developed in our laboratories for light and electron microscopy. This microwave-accelerated technique employs periodic acid, thiocarbohydrazide and silver methenamine. It stains basement membrane or Type IV collagen brown and type III collagen (reticulin), axons, Schwann cells, endoneurium and perineurium black. Epoxy sections of repaired and excised nerves were also compared by toluidine blue (tb) staining. Comparison of the sections of control and repaired nerves was done by computer-assisted microscopic image analysis using an Olympus CUE-2 Image Analysis System.

Susceptibility of the diabetic nerve to chronic compression.

This study tested the hypothesis that the peripheral nerve in the presence of diabetes is more susceptible to chronic nerve compression than it is in the nondiabetic rat. A 1-cm length of sciatic nerve was subjected to chronic compression by banding with a Silastic tube in normal and in streptozotocin-induced diabetic rats. After six months of banding, both the amplitude and conduction velocity of the diabetic banded sciatic nerve were significantly reduced (p less than 0.001) in comparison with the nondiabetic banded rats. These results suggest that in the presence of hyperglycemia, the peripheral nerve is more susceptible to chronic compression.

Effects of capsaicin applied locally to adult peripheral nerve. II. Anatomy and enzyme and peptide chemistry of peripheral nerve and spinal cord

1.(1) Capsaicin solution was applied for 15 min around a 1 cm length of sciatic nerve in the mid upper leg of adult rats.2.(2) Electron microscopic examination of the nerve in the treated region after 14 days shows no signs of degeneration of either myelinated or unmyelinated fibres attributable to the capsaicin.3.(3) Fluoride resistant acid phosphatase FRAP disappears from the central terminals of the treated nerve by 7 days.4.(4) 1.5 mM capsaicin is sufficient to produce a complete reduction of FRAP in the spinal cord.5.(5) The peptides substance P and cholecystokinin (CCK) are markedly depleted in the region of spinal cord terminations of the treated nerve at 14 days.6.(6) Substance P and CCK are not affected in spinal cord regions other than in the unmyelinated afferent terminal zone. Similarly neurotensin and neurophysin which are not present in afferent fibres are not influenced by capsaicin treatment of the sciatic.7.(7) It is concluded that there are chemical changes in the spinal cord terminals of fine afferents after local peripheral capsaicin.

Rate of fast axoplasmic transport in mammalian nerve fibres.

1. Fast axoplasmic transport in mammalian nerve fibres was determined by the presence of a crest of activity in the sciatic nerve after injection of [(3)H]leucine into the L7 dorsal root ganglion or the L7 motoneurone region in the ventral horn region of the spinal cord. After incorporation into proteins by the cell bodies, a rate of transport close to 410 mm/day was found for cat sensory nerves. A closely similar rate was found in the motor and sensory sciatic nerve fibres of the monkey, dog, rabbit, goat and rat. In the longer nerves where longer downflow times were possible, there was no decrement of rate with distance, or presence of later appearing crests of activity indicative of multiple fast transport systems.2. The rate of fast transport found in the long L7 dorsal roots of the rhesus monkey was the same as that in the corresponding length of sciatic nerve and the same fast rate was shown by the crest of activity ascending in the dorsal columns of the spinal cord.3. Labelled activity was found present inside myelinated nerve fibres ranging in diameter from 3 to 23 mum in nerve segments taken at the forward part of the crest suggesting that the rate of fast axoplasmic transport is independent of fibre diameter.