Effects of Exercise on Neuropathy in Streptozotocin-Induced Diabetic Rats

OBJECTIVE: To evaluate the effects of early regular exercise and to assess the electrophysiological and histopathological findings of the rat tail nerve in relation to the timing of exercise training for swimming exercise in rats with diabetic neuropathy. METHODS: We used 70 Sprague-Dawley male rats, and the experimental group comprised 60 rats, and the control group comprised 10 rats. Diabetes was induced by intraperitoneal injection of streptozotocin. Blood glucose concentrations were measured in tail vein blood samples. The experimental group was divided into 6 subgroups according to insulin treatment and swimming exercise: group 1, diabetic control; group 2, insulin treated; group 3, insulin untreated with early swimming exercise; group 4, insulin treated and early swimming exercise; group 5, insulin treated and late swimming exercise; and group 6, insulin untreated with late swimming exercise. Sensory and motor nerve conduction studies were performed weekly up to the 13th week using rat tail nerves. The effect on structural diabetic neuropathy was assessed by morphometry and ultrastructural examination of the rat tail nerve fiber at the 14th week. RESULTS: An exercise effect was observed in the insulin treated groups, but it was not observed in the insulin untreated groups. The sensory nerve conduction study in the rat tail revealed significantly prolonged latency and decreased amplitude in groups 1 and 6, and a further delay was observed in group 5 when compared to group 4. Decreased thickness of myelin was found in groups 1 and 6 through morphometry. CONCLUSION: Early regular exercise programs in addition to conventional insulin treatment may retard the progression of diabetic peripheral neuropathy.

Suprascapular Nerve Conduction Study: Comparative Analysis between Surface and Needle Recording Methods in Normal Subjects

OBJECTIVE: An electromyographic examination is often utilized to confirm the diagnosis of suprascapular neuropathy in patients with shoulder pain and dysfunction. The purpose of this study was to compare two recording methods (surface and monopolar needle electrode recordings) for the evaluation of suprascapular nerve. METHOD: Twenty-two healthy subjects were tested with each method. Differences between the recording methods were compared for compound muscle action potential (CMAP) latencies and amplitudes. And the parameters obtained from two recording methods were correlated. RESULTS: The mean age was 43.6+/-12.4 years (range: from 23 to 72 years old). The surface recordings appeared to give a more reproducible latency and amplitude of CMAP of the infraspinatus. The surface recorded CMAP latency and amplitude were 2.58+/-0.46 ms, and 12.6+/-2.7 mV, respectively. Those of the needle electrode recording were 2.49+/-0.41 ms and 27.6+/-6.55 mV, respectively. The two recordings were significantly correlated in latency (r=0.876, p<0.05) and amplitude(r=0.484, p<0.05). CONCLUSION: Considering the invasiveness of study and compliance of the patient, the surface electrode recording may be prudent for the convenient assessment and follow up studies in suprascapular nerve conduction study.

The Preventive Effect of Nimodipine on the Cisplatin Induced Neuropathy

OBJECTIVE: Cisplatin has effectiveness in the treatment of solid tumor by active cytotoxic action, but with significant side effects such as peripheral neuropathy. To investigate the prevention of neuropathy, nimodipine was examined. METHOD: Fifty female rats (Sprague-Dawley strain; BW 210-260 g, 12-15 week old) were used: control group; cisplatin group; cisplatin-nimodipine 2 week group, 10; ciplatin-nimodipine 4 week group; base group. Peripheral neuropathy was induced by intraperitoneal injection of the cisplatin (0.04 mg/ml, 1 ml/kg/ip/ for 2 weeks). Nimodipine was injected intraperitoneally for 2 weeks and 4 weeks in cisplatin-nimodipine 2 week group and cisplatin-nimodipine 4 week group, respectively. Motor and sensory nerve conduction studies were done using in rat tail nerve from the beginning and biweekly till to 10th week. RESULTS: Weight reduction was significant in cisplatin group at 2nd week (p0.05). CONCLUSION: The neurotoxicity of cisplatin revealed in motor and sensory neurons. The neuropathy has recovered to control value in 6th week and the preventive effect of nimodipine was transient.

Histochemical Findings of Soleus in Relation to the Severity of Injury and Duration of Exercise in Sciatic Nerve Injured Rats

OBJECTIVE: To investigate the histopathological findings of soleus muscle in relation to the severity of injury and the duration of treadmill exercise in rats with sciatic nerve damage. METHOD: Sciatic nerve of seventy rats was compressed with haemostatic forceps. The experimental group was divided into 4 subgroups according to the intensity and duration of injury: group 1, first degree compression for 5 seconds; group 2, first degree for 30 seconds; group 3, third degree for 5 seconds; and group 4, third degree for 30 seconds. Treadmill exercise was done for either 30 minutes or 2 hours a day, 5 days a week for 4 weeks. Histochemical study of soleus was done before nerve compression and 1 week, 4 weeks after compression. RESULTS: The fiber diameter of soleus was larger in the experimental group at 4 weeks (p<0.05). The intensity of injury had greater impact on the recovery of fiber diameter than the duration. Thirty minute exercise was seen to have a earlier recovery of fiber diameter than 2 hours. CONCLUSION: These results may provide the basic data to clarify the neurological recovery in relation to the severity of injury, and to help establishing adequate duration of exercise after nerve damage.

Effect of Therapeutic Exercise according to Degree of Injury in Sciatic Nerve Damaged Rat

OBJECTIVE: To investigate the effects of treadmill running and swimming exercise for the functional and electrophysiological recovery in rats with sciatic nerve damage, and to evaluate the patterns of recovery according to various degree of intensity and duration of injury. METHOD: Sixty male Sprague-Dawley rats (200~250 g) were used, and divided into the control and the experimental groups. Crushing injuries to the sciatic nerve at the sciatic notch was manipulated using a hemostatic forcep, treadmill and swimming exercise programs were performed for 30 minutes on a daily basis, 5 days a week during the 4 week period. The experimental group was divided into 2 sub-groups in correlation with the intensity of injury, and into 5 and 30 seconds group in correlation with the duration of injury. The test results were analysed by sciatic nerve functional index (SFI) that was obtained through walking tract analysis, and by the amplitude of compound muscle action potentials in calf muscles through the sciatic motor nerve conduction study. RESULTS: 1) After 4 weeks following sciatic nerve injuries, the SFI were -21.8+/- 10.8, -23.1+/- 7.0, -32.5+/- 9.1 in treadmill, swimming, and control groups, respectively. Treadmill and swimming groups showed markedly improved function compared to the control group. Amplitudes of sciatic nerve compound muscle action potentials in calf muscle were 21.2+/- 6.5, 15.9+/- 5.8, 12.5+/- 2.0 mV in treadmill, swimming, and control groups respectively, and revealed marked electrophysiological improvement in treadmill group. 2) The results concerning the intensity and the duration of injury, nerve recovery patterns showed the most significant improvement in the first degree-5 seconds group in both treadmill and swimming exercise programs. CONCLUSION: These findings suggest that the treadmill and swimming exercises have significantly better effect in the regeneration of damaged sciatic nerve than that of control, and the intensity of injury was a more important factor in the recovery of nerves compared to the duration of injury.

H MR Spectroscopy on Parkinson's-like Syndrome Induced by Manganese Intoxication: A Case Report

Manganese intoxificaton is a well-known cause of Parkinson's like syndrome. We describe a 46-year-old man who had been occupationally exposed to manganese and report the case with hydrogen magnetic resonance spectroscopy (1H MRS). Ratios of N-acetyl-aspartate (NAA) to creatine were significantly reduced in basal ganglia regions compared to normal subjects. The level of NAA was decreased in basal ganglia regions may indicate neuronal dysfunction. 1H MRS can provide detailed information of brain damage, therefore the 1H MRS is very useful in diagnosis of manganese intoxification.