The effects of nerve growth factor (NGF) on crushed sciatic nerve regeneration were studied in 30 rats, with 60 bilateral nerves. The nerves were crushed at a site 6 mm distal to the sciatic notch by the standard technique and 3 mm wide crush injuries were created. Then 2.1 microliters of normal saline in the control groups and an equal volume of NGF solution (containing 1 microgram of NGF) in the NGF-treated groups was injected into the crush sites and followed for 12, 28, and 56 days, respectively. At the end of the observation, electrophysiological evaluation was carried out; then samples 10 mm distal to the crush site were removed and prepared for histological and morphometric studies. Evoked muscle action potential (MAP) was recorded in 50% of the NGF-treated group at 12 days but not in the control group; the difference was statistically significant (P < 0.05). The motor nerve conduction velocity (MNCV) was increased in NGF-treated groups compared with control groups at 28 and 56 days (P < 0.05). Morphometrically, significantly more regenerated myelinated fibers (RMFs) were seen at 12 days, and larger diameter RMFs were found at 12, 28, and 56 days in NGF-treated groups than in control groups. These results indicate that topically applied NGF stimulates nerve regeneration and promotes function recovery in crushed rat sciatic nerves.

The effects of topical GM1 ganglioside on crushed rat sciatic nerve regeneration were studied in this presentation. Thirty-four rats, with 68 bilateral sciatic nerves, were divided into seven groups: one group of four rats for measurement of normal motor nerve conduction velocity (MNCV), three as controls, and another three in the GM1-treated groups. Sciatic nerves were exposed and crushed at a site 6 mm distal to the sciatic notch by the standard technique. In this manner, 3 mm wide crush injuries were created. Then 2.1 microliters of normal saline was injected into the crush site in the control groups and an equal volume of GM1 solution (containing 10 micrograms GM1) was injected into the GM1-treated groups. Electrophysiological, histological, and morphometric evaluations were carried out at 12, 28, and 56 days. A significantly higher muscle action potential (MAP) rate was found in the GM1-treated group (70%) vs. the controls (none) at 12 days (P < 0.005), and increased MNCV was found in the GM1-treated groups at both 28 and 56 days, especially at 56 days, when it was 39.59 +/- 9.23 m/sec vs. 31.42 +/- 4.07 m/sec in controls (P < 0.05). Morphometrically, there were more regenerated myelinated fibers (RMFs) at 12 days, and larger diameter of RMFs were observed at 12, 28, and 56 days in the GM1-treated groups.

The implantation of a microvascular polyester prosthesis (MPP) (internal diameter 1 mm, length 10 mm) in the carotid arteries was studied in 48 Sprague-Dawley rats. The left carotid artery was resected to 7 mm in length and replaced with MPP by means of sleeve anastomoses. Postoperatively the patency was monitored with Doppler ultrasound at 24 and 72 hr, and at 1, 2, 3, 4, 8, and 12 weeks and was confirmed either by direct inspection intraoperatively or by angiography at the time of removal. At each monitoring time, all the thrombosed and some selected patent grafts were removed and prepared for scanning electron microscopy (SEM) study. The early patency rate was 100% within 24 hr, and the cumulative long-term patency rate was 77.1% at 12 weeks. Rapid and complete endothelial lining (EL) restoration was demonstrated 3 weeks after operation, which provided a smooth and nonthrombogenic surface, and contributed to the long-term patency. Ten of the 11 failed grafts occurred within 3 weeks, that is, before EL, due to thrombosis. These observations indicate that MPP can be successfully used as arterial conduits in rats, and an enhanced patency rate may be expected with the use of anticoagulants or endothelial cell seeding for prevention of early thrombosis.