| Objective To investigate the effect exerted by the treatment of ginsenoside Rg1 on regeneration of damaged sciatic nerve and its mechanism, and then provide the basis of animal experiments for the clinical medical treatment of peripheral nerve injury. Method The health Wistar rats of which the right sciatic nerve was transected and sutured epineurium immediately were used for animal model damaged in sciatic nerve. Following the successfully finished models, the model rats were randomly assigned into 2 groups consisting of 40 animals each. Test group received the ginsenoside Rg1 dissolved in saline at dose of 1.5mg/kg by intraperitoneal injection, and control group received saline throughout the experimental period in the same manner above. All animals were treated once a day for 4 weeks. The sciatic nerve stump adjacently distal to the injured site was harvested at the end of 2 weeks after surgery. The expression of NGF protein in the sciatic nerve tissue was evaluated by methods of immunohistochemistry and image analysis. At 4 weeks, 8 weeks and 12 weeks interval after operation, the denervated changes of rats, the recovery rate of wet weight of gastrocnemius muscle, and the sciatic function index (SFI) were measured; also were the complex muscular action potential (CMAP) and motor nerve conduction velocities (MNCV) measured with Nerve-Electrophysiological instrument. By the same time, distal nerve to the injured site was processed by histological procedure, and then the histological changes in the regenerative sciatic nerve were assessed under microscope. The axonal regeneration and functional situation of the sciatic nerve were further evaluated by the trace-back of fluorescence in the nerve at the end of 12 weeks after surgery. Results All the 80 enrolled rats were involved in the result analysis. (1) The dyeing density and the dyeing area of NGF protein expressed of rats from the group treated with ginsenoside Rg1, which were 120.15±25.19 and 88.85±15.34, significantly and statistically were higher than those of animals from control group respectively, which were 91.60±16.26 and 59.43±18.97. (2) The denervated changes of rats from the test group in the muscle atrophy, the swelling and ulcer of toe, stretch and ascend action of paw is better than those of animals from control group. (3)The SFI in rats of test group at the end of 4, 8, or 12 weeks after surgery, which were -63.66±4.54, -42.42±6.20, or -31.82±7.26, more apparently increased as compared with those of the animals of control group, which were -76.29±6.53, -58.44±9.38, or -44.56±9.23, respectively. (4) The results of nerve- electrophysiology showed that the CMAP values of rats of test group were 3.90±0.75, 7.84±1.16, and 17.05±2.78 mV at 4, 8, and 12 weeks after operation, respectively, while those of control animals were 2.33±0.79, 5.23±1.53, and 10.78±1.94 mV; that the MNCV values of test group rats were 28.69±5.01, 42.74±6.61, and 49.54±7.03 m/s, respectively, whereas those of control animals were 15.65±6.02, 26.17±6.02, and 38.24±6.98 m/s; and that both CMAP and MNCV values in rats from test group at the ends of 4,8, and 12 weeks after operation were all significantly higher than those in control animals, respectively. (5)There were significant elevations in the recovery rates of wet weight of gastrocnemius muscle of rats from test group, which were (51.56±3.83) %, (66.94±3.69) %, and (80.92±3.94) % at 4, 8, and 12 weeks after surgery, as compared with those of control rats which are (45.16±2.16) %, (58.99±5.34) %, and (72.13±4.96) %, respectively. (6) The axon and myelin of the regenerative sciatic nerve in rats of test group are much denser and regular than those in control animals at the ends of 4, 8, an 12 weeks after surgery, respectively. (7) At the end of 12 weeks after surgery, the amount and intensity of fluorescent in the spinal ganglia of rats from the test group were dramatically higher than the control values. Conclusion (1) The treatment with ginsenoside Rg1 can effectively enhance the regeneration of the sciatic nerve from damage, and improve the quantity and quality of regenerative nerve fibers. Moreover, the restoration of conduction velocity of regenerative nerve fibers and the limb functions have been improved. Also can Ginsenoside Rg1 prevent effectively atrophy of skeletal muscles following sciatic nerve injury. (2) Ginsenoside Rg1 could improve the functional rehabilitation of injured peripheral nerves through increasing the level of endogenous NGF protein. (3) The present study can provide significant animal experimental data for clinical trial to apply ginsenoside Rg1 to enhance the regeneration of damaged peripheral nerves. |
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