Comparison of results obtained with standard and inside out vein graft techniques and their implication on neurotrophin expression in repair of nerve defect: an experimental study.

Standard vein graft (SVG) and inside out vein graft (IOVG) techniques to promote peripheral nerve regeneration have been widely studied since last two decades. In this experimental study, we attempted to compare these two techniques and analyze the differences in the expression of the neurotrophins during peripheral nerve regeneration. Thirty-six male Wistar rats were used in this sciatic nerve transection model and were divided into two experimental groups (SVG and IOVG) and one sham operated control group. An overall defect of 10 mm was made in the sciatic nerve of the animals in the experimental groups. Each group consisted of two time intervals of 6 and 12 weeks (n = 6). After each experimental interval, sciatic functional index (SFI) along with area and diameter of the axons and fibers of each group were calculated. Muscle mass measurements were also evaluated to see any functional recovery in the groups. Expression of neurotrophins in the graft and distal stump were analyzed with the help of RT-PCR. SFI obtained from walking track analysis showed poor motor recovery in the experimental groups during both time intervals. No significant differences in the histological, morphometric (P > 0.05), and muscle mass measurements (P > 0.05) between the two experimental groups were observed. Analysis of RT-PCR data exhibited an increase in the expression of NT-3 with time in both the grafts (6 weeks 0.428 ± 0.392, 12 weeks 1.089 ± 0.455, P < 0.05) and distal stump (6 weeks 0.411 ± 0.306, 12 weeks 0.807 ± 0.303, P < 0.05) of the SVG group. The study concludes that there is no substantial difference in the nerve regeneration ability between both the techniques. Also, the difference in the level of NT-3 between SVG and IOVG suggests a distinct regulation of NT-3 in peripheral nerve regeneration.