OBJECTIVETo assess the effect of cyclosporine A (CsA) loaded in chitosan conduit on bridging the sciatic nerve defects in a rat model.

METHODSA 10 mm sciatic nerve defect was bridged using a chitosan conduit filled with 10 μl carrier-drug dilution (10 μg/L CsA). In control group, the conduit was filled with the same volume of carrier dilution alone. The regene-rated fibers were studied 4, 8 and 12 weeks after surgery.

RESULTSThe functional study confirmed faster recovery of the regenerated axons in treatment group than control group (P<0.05). There was statistically significant difference of the gastrocnemius muscle weight ratios between treatment and control groups (P<0.05). Morphometric indices of regenerated fibers showed that the number and diameter of the myelinated fibers in CsA-treated animals were significantly higher than those in control group. In immunohistochemistry, the location of reactions to S-100 in CsA group was clearly more positive than control group.

CONCLUSIONCsA loaded in a chitosan conduit results in improvement of functional recovery and quantitative morphometric indices of sciatic nerve. It is easily available without any complications compared with its systemic administration.

Animals ; Chitosan ; Cyclosporine ; administration & dosage ; pharmacology ; Immunohistochemistry ; Nerve Regeneration ; drug effects ; Rats ; Sciatic Nerve ; chemistry ; injuries

OBJECTIVE: To quantitatively investigate the effects of Ringer's solution with different concentrations of alcohol (1%～80%) on biphasic compound action potentials (AP) from frog sciatic nerve trunk, and their recoveries from alcohol effects. METHODS: Individual segments of frog sciatic nerve trunk with a length of 6 to 8 cm were prepared. Ringer's solution with different concentrations of alcohol (0%, 1%, 2%, 4%, 8%, 16%, 32%, 48%, 64% and 80%) was applied onto the segment of the trunk between the stimulus and ground electrodes via an agent reservoir which was newly armed in a nerve trunk shielded chamber for 5 minutes. The nerve trunk was respectively electro-stimulated to generate the biphasic compound AP which was recorded using the experimental system of BL-420F. This was followed by 5 times washout plus 5 min administration with Ringer's solution before recovery recording of AP. RESULTS: Compared to normal Ringer's solution, Ringer's solution with alcohol at ≤4% did not have dramatic impacts on the AP amplitude and conduction velocity, while Ringer's solution with alcohol at ≥8% there was significant decrease in these two parameters. Ringer's solution with alcohol at the conentrations of 16%, 32% and ≥48% could prevent a small proportion (30%), a large proportion (90%) and all (100%) of sciatic nerve trunks, respectively, from generating AP. Washout with normal Ringer's solution after alcohol application at the concentration of ≤32%, AP could totally recover to normal status. While alcohol at the concentration of 48%, 64% and 80%, the probabilities to regenerate APs were 90%, 40% and 0%, and the AP amplitudes were decreased to 60%, 36% and 0%, respectively. After washout, AP conduction velocity showed no difference with alcohol at the concentration of ≤8% when compared with that before washout, while it could not be recovered to normal under alcohol at ≥16%. CONCLUSION Ringer's solution with different concentrations of alcohol exerts different effects on biphasic compound AP amplitude and conduction velocity. Hopefully, our findings could be helpful for the alcoholic usage and its recovery from alcoholic damage.
Action Potentials ; Animals ; Anura ; Ethanol ; pharmacology ; Ringer's Solution ; pharmacology ; Sciatic Nerve ; drug effects

OBJECTIVETo investigate the effect of 2,5-hexanedione (HD) on degradation of low-molecular-weight neurofilaments (NF-L) in nervous tissue of rats, and to explore the molecular mechanism of n-hexane neuropathy.

METHODSFifty male Wistar rats were randomly divided into one-week poisoning group (n = 10), two-week poisoning group (n = 10), three-week poisoning group (n = 10), four-week poisoning group (n = 10), and control group (n = 10). In the four poisoning groups, a rat model of n-hexane neuropathy was established by intraperitoneal injection of HD (400 mg/kg/d). The change in the sciatic nerve ultrastructure of each rat was observed under an electron microscope. The progression of HD-induced peripheral neuropathy was evaluated using a gait scoring system. The degradation rates of NF-L in the sciatic nerve and spinal cord of each rat were measured by Western Blotting.

RESULTSThe rats showed decrease in muscle strength and abnormal gait after two weeks of HD poisoning and mild or moderate paralysis after four weeks of HD poisoning. The sciatic nerve showed degenerative change, according to electron microscope observation. Compared with the control group, the two-week poisoning group, three-week poisoning group, and four-week poisoning group had the NF-L degradation rates decreased by 25.8%, 70.4%, and 69.7%, respectively, in the supernatant fraction of sciatic nerve, and by 14.7%, 64.6%, and 67.3%, respectively, in the sediment fraction of sciatic nerve, all showing a significant difference (P < 0.01). Compared with the control group, the one-week poisoning group had the NF-L degradation rate decreased by 33.87% in the supernatant fraction of spinal cord, the four-week poisoning group had the NF-L degradation rate increased by 16.2% in the supernatant fraction of spinal cord, and the one-week poisoning group and two-week poisoning group had the NF-L degradation rates decreased by 46.3% and 13.0% in the sediment fraction of spinal cord, all showing a significant difference (P < 0.01).

CONCLUSIONHD poisoning significantly inhibits NF-L degradation in the sciatic nerve, which may be associated with NF degeneration and accumulation in the axons of patients with n-hexane neuropathy.

Animals ; Hexanes ; poisoning ; Hexanones ; pharmacology ; Male ; Nerve Tissue ; drug effects ; metabolism ; physiopathology ; Neurofilament Proteins ; drug effects ; metabolism ; Rats ; Rats, Wistar ; Sciatic Nerve ; drug effects ; metabolism ; physiopathology

AIMTo explore the effect of Simvastatin on the regeneration of sciatic nerve with crush injury in rats.

METHODSAnimals were randomized into the following experimental groups: Simvastatin-treated, vehicle and sham-operated groups. Sciatic nerves with crush injury were performed. After surgery, the functional evaluation of nerve recovery, electrophysiologic assessment, histological assessment, serum IL-6 and lipid were performed.

RESULTSThe toe spread index of Simvastatin-treated rats after operation was higher significantly than vehicle rats at 5 d and 8 d (P<0.05). CMAP was higher and NCV was faster (P < 0.05). The serum IL-6 at 5 d of post-operation was significant lower (P < 0.05). Total serum cholesterol of Simvastatin-treated animals was higher than that of other animals (P < 0.05) at 2 weeks of post-operation. The histological analysis showed that the numbers of myelinated axons and the thickness of myelin sheath of Simvastatin-treated crush injury animals at 4 weeks of post-operation were more than that of vehicle animals.

CONCLUSIONThe present study showed that Simvastatin could promote the regeneration of the sciatic nerve after crush injury in rats, partly through inhibiting immune and inflammatory responses and making the balance of serum cholesterol during these processes.

Animals ; Female ; Nerve Crush ; Nerve Regeneration ; drug effects ; physiology ; Rats ; Rats, Sprague-Dawley ; Sciatic Nerve ; drug effects ; injuries ; physiology ; Simvastatin ; pharmacology

OBJECTIVETo evaluate the local effect of vascular endothelial growth factor (VEGF) on transected sciatic nerve regeneration.

METHODSSixty male white Wistar rats were divided into four experimental groups randomly (n equal to 15). In transected group the left sciatic nerve was transected and the stump was fixed to adjacent muscle. In treatment group the defect was bridged using a silicone graft filled with 10 microlitre VEGF. In silicone group the graft was filled with phosphate-buffered saline. In sham-operated group the sciatic nerve was exposed and manipulated. Each group was subdivided into three subgroups with five animals in each and nerve fibers were studied 4, 8 and 12 weeks after operation.

RESULTSBehavioral test, functional study of sciatic nerve, gastrocnemius muscle mass and morphometric indices confirmed a faster recovery of regenerated axons in VEGF group than in silicone group (P less than 0.05). In immunohistochemical assessment, reactions to S-100 in VEGF group were more positive than that in silicone group.

CONCLUSIONLocal administration of VEGF will improve functional recovery and morphometric indices of sciatic nerve.

Administration, Topical ; Animals ; Nerve Regeneration ; drug effects ; Rats ; Rats, Wistar ; Sciatic Nerve ; surgery ; Vascular Endothelial Growth Factor A

OBJECTIVETo investigate the effect of pyrroloquinoline quinone (PQQ) on nerve regeneration of transected sciatic nerve in animal models.

METHODSForty SD rats weighing 220-240 g were randomized into a PQQ group (n = 20) and a control group (n = 20). Each animal underwent sciatic nerve transection operation. After the operation, PQQ 0.5 ml (250 microg/Kg) was injected at the operation site in the PQQ group, while the same volume of normal saline was delivered in the control group. Nerve functional evaluation, electrophysiological index recording were carried out according to the experimental design. Newly generated nerve specimens were harvested 12 weeks postoperatively for morphological studies.

RESULTSIn the PQQ group there was a good nerve regeneration and the sciatic nerve function, sciatic nerve function index, electrophysiological index and morphological appearance were superior to the control group (P < 0.05).

CONCLUSIONSPQQ has a remarkable effect in enhancing nerve regeneration of transected peripheral nerve.

Animals ; Male ; Nerve Regeneration ; drug effects ; PQQ Cofactor ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Sciatic Nerve ; injuries ; pathology ; physiology

OBJECTIVETo study the effect of captopril on the nervous function in rabbits exposed to vibration.

METHODSRabbits were divided into vibration group, intervention group, and control group. Vibration group and intervention group were exposed to (tested by) vibration. Captopril was given to intervention group from the 11th day of vibration exposure. Somatosensory evoked potential (SEP) and motor nervous conduction function (MCF) were measured and analyzed in each group before and after vibration exposure.

RESULTSThe latent periods of N1, P1 and N2 of SEP in vibration group after vibration exposure were (30.76 +/- 4.26), (41.91 +/- 6.67), and (45.29 +/- 5.81) ms respectively, and in intervention group after vibration exposure were (27.00 +/- 3.04), (35.07 +/- 4.20) and (41.15 +/- 3.19) ms respectively. Compared with intervention group before and after exposure, and control group, the latent periods of each wave of SEP were delayed significantly (P < 0.05). The nervous conduction velocity, the distant wave amplitude, and the distant potential period of sciatic nerve in vibration group after vibration exposure were significantly different from those in intervention group [(35.69 +/- 4.37) m/s, (1.55 +/- 0.73) microV, (8.16 +/- 0.71) ms respectively vs (52.20 +/- 5.13) m/s, (2.89 +/- 0.36) microV, (7.26 +/- 0.77) ms respectively (P < 0.01)].

CONCLUSIONCaptopril may improve the impairment of nervous functions to a certain degree in rabbits exposed to vibration.

Animals ; Captopril ; pharmacology ; Evoked Potentials, Somatosensory ; drug effects ; Female ; Male ; Neural Conduction ; drug effects ; Rabbits ; Sciatic Nerve ; drug effects ; physiology ; Vibration ; adverse effects

OBJECTIVETo explore the effect of 2,5-hexanedione (2,5-HD) on the levels of nerve growth factor (NGF) in sciatic nerve of rats and motor-neurons.

METHODA total of 50 Wistar rats were randomly designed into five groups and intoxicated with 400 mgxkg(-1)xd(-1) 2,5-HD for 0, 7, 14, 21, 28 d. Immunohistochemistry and real-time PCR were used to detect the levels of NGF and NGF mRNA. Motor neuron VSC4.1 cells were administrated with 0, 2.5, 5.0, 10.0, 20.0 mmol/L 2,5-HD for 24 h and 10.0 mmol/L 2,5-HD was chosen to intoxicated VSC4.1 cells for 0, 1, 3, 6, 12, 24, 48 h respectively. Immunofluorescence technique was selected to detect the levels of NGF.

RESULTSThe NGF level in sciatic nerve of rats administrated with 400 mgxkg(-1)xd(-1) 2,5-HD showed increase tendency at begin and then decrease after exposure. The NGF mRNA level in 14 d (2(-DeltaDeltaCt)= 3.46), 21 d (2(-DeltaDeltaCt)= 5.28) and 28 d (2(-DeltaDeltaCt)= 3.10) were higher than those in 0 d (2(-DeltaDeltaCt)= 1) and 7 d (2(-DeltaDeltaCt)= 0.78). In vitro tests of VSC4.1 cells showed that NGF levels in 5.0 mmol/L (43.24 +/- 7.52), 10.0 mmol/L (43.48 +/- 10.86) and 20.0 mmol/L (63.13 +/- 10.68) were higher than those in 0 mmol/L (16.32 +/- 4.20)(q values were 19.92, 19.72, 32.78, respectively, P < 0.01) and 2.5 mmol/L (19.78 +/- 2.66) (q values were 17.50, 17.42, 30.63, respectively, P < 0.01) in 24 h and the NGF level in 20.0 mmol/L was higher than those in 5.0 mmol/L (q = 13.04, P < 0.01) and 10.0 mmol/L (q = 11.71, P < 0.01). The NGF levels of VSC4.1 cells with 10.0 mmol/L 2,5-HD in 6 h (18.66 +/- 2.89), 12 h (23.14 +/- 6.08), 24 h (27.66 +/- 6.11) and 48 h (17.25 +/- 3.05) were increased compared with that in 0 h (10.18 +/- 1.81) (q values were 9.64, 15.74, 21.76, 8.50, respectively, P < 0.01), 1 h (9.31 +/- 1.28) (q values were 10.28, 16.17, 21.95, 9.20, respectively, P < 0.01) and 3 h (10.44 +/- 2.13) (q values were 9.25, 15.24, 21.17, 8.10, respectively, P < 0.01), and NGF levels in 12 h and 24 h increased compared with those in 6 h (q values were 5.24, 10.77, respectively, P < 0.01) and 48 h (q values were 7.31, 13.26, respectively, P < 0.01).

CONCLUSION2,5-HD could increase NGF levels in sciatic nerve of rats and motor-neurons, and the dose or time dependent effects were observed in this study.

Animals ; Cell Line ; Hexanones ; toxicity ; Male ; Motor Neurons ; drug effects ; metabolism ; Nerve Growth Factor ; metabolism ; Rats ; Rats, Wistar ; Sciatic Nerve ; drug effects ; metabolism

Animals ; GAP-43 Protein ; metabolism ; Ganglia, Spinal ; drug effects ; metabolism ; Nerve Block ; Rats ; Rats, Wistar ; Sciatic Nerve ; drug effects ; injuries ; Tetrodotoxin ; pharmacology

OBJECTIVETo investigate the dynamic changes of alpha-tubulin, beta-tubulin and beta-actin in sciatic nerve of hen with organophosphorus ester-induced delayed neuropathy (OPIDN).

METHODSOPIDN was induced in 10-month-old Roman hens by daily subcutaneous administration of 30 mg/kg methamidophos for 15 days. Hens were sacrificed 2, 10, and 23 days respectively after manifesting neuropathy. The sciatic nerves were dissected, homogenized and used for the determination of the alpha-tubulin, beta-tubulin and beta-actin levels by western blotting.

RESULTSThe levels of alpha-tubulin in supernatant of sciatic nerves were decreased by 6%, 15% and 25% respectively on day 2, 10 and 23 respectively, while those in pellet remained almost unchanged. beta-tubulin were decreased by 27%, 6%, 19% in pellet and 1%, 21%, 22% in supernatant of sciatic nerves on 2, 10 and 23 days. Beta-actin level in pellet of sciatic nerve increased by 24%, 48% and 17% on day 2, 10 and 23, and little changes were observed in supernatant.

CONCLUSIONMethamidophos may induced changes of alpha-tubulin, beta-tubulin and beta-actin levels in sciatic nerve of hen, which may be one of the mechanism of the contribution to the occurrence and development of OPIDN.

Actins ; metabolism ; Animals ; Chickens ; Female ; Insecticides ; toxicity ; Organothiophosphorus Compounds ; toxicity ; Sciatic Nerve ; drug effects ; metabolism ; Tubulin ; metabolism