BACKGROUNDWith economic growth and urbanization there have been significant changes in the life style and diet of urban residents in large cities of China, which is experiencing a rapid increase in the prevalence of diabetes. While high prevalence of diabetes has been reported, little is known of the long-term effects of diabetes in such a large population. The aim of this study was to estimate the morbidity rate of diabetic peripheral neuropathy (DPN) in a Chinese urban diabetic population with more than 10 years' disease duration, and evaluate the relevant risk factors. The clinical manifestation of DPN and pain status was also assessed.

METHODSFive hundred and sixty-five diabetes patients were recruited into the study. Symptoms and examination helped diagnose neuropathy. The clinical manifestation of DPN was assessed with a visual analog pain score (VAS). Diabetic complication status was determined from medical records. Serum lipids and lipoproteins, glycosylated hemoglobin (HbA1c), and the urinary albumin excretion rate were measured.

RESULTSThe morbidity rate of DPN was 46.6%. HbA1c, hyperlipidemia, and retinopathy were significantly associated with neuropathy, and these risk factors were correlated with other diabetic micro and/or macrovascular complications. The average VAS pain score of the DPN patients was 4.12 ± 2.07. Severe and moderate pain was experienced by 11.4% and 40.5% respectively of DPN patients. About 3.7% of diabetic subjects had lower limb ulcer or amputation.

CONCLUSIONSThe morbidity rate of DPN for diabetic patients with > 10 years duration is very high compared to the range reported for other populations in the world. The risk factors for DPN include HbA1c, hyperlipidemia, and retinopathy. In long-standing diabetic patients, DPN was not associated with diabetic duration, and half of the DPN patients experienced considerable daily suffering.

Aged ; China ; Diabetic Neuropathies ; epidemiology ; metabolism ; physiopathology ; Female ; Glycated Hemoglobin A ; metabolism ; Humans ; Hyperlipidemias ; epidemiology ; metabolism ; physiopathology ; Male ; Middle Aged ; Pain ; etiology ; Risk Factors ; Urban Population

PURPOSE: We previously reported that insulin resistance, low high-density lipoprotein (HDL) cholesterol, and glycaemic exposure Index are independently associated with peripheral neuropathy in Korean patients with type 2 diabetes mellitus. We followed the patients who participated in that study in 2006 for another 6 years to determine the relationship between insulin resistance and neuropathy. MATERIALS AND METHODS: This study involved 48 of the original 86 Korean patients with type 2 diabetes mellitus who were referred to the Neurology clinic for the assessment of diabetic neuropathy from January 2006 to December 2006. These 48 patients received management for glycaemic control and prevention of diabetic complications in the outpatient clinic up to 2012. We reviewed blood test results and the nerve conduction study findings of these patients, taken over a 6-year period. RESULTS: Low HDL cholesterol and high triglycerides significantly influenced the development of diabetic neuropathy. Kitt value (1/insulin resistance) in the previous study affected the occurrence of neuropathy, despite adequate glycaemic control with HbA1c <7%. Insulin resistance affected the development of diabetic neuropathy after 6 years: insulin resistance in 2006 showed a positive correlation with a change in sural sensory nerve action potential in 2012. CONCLUSION: Diabetic neuropathy can be affected by previous insulin resistance despite regular glycaemic control. Dyslipidaemia should be controlled in patients who show high insulin resistance because HDL cholesterol and triglycerides are strongly correlated with later development of diabetic neuropathy.
Adult ; Diabetes Mellitus, Type 2/*metabolism/*physiopathology ; Diabetic Neuropathies/*metabolism/*physiopathology ; Female ; Humans ; Insulin Resistance/*physiology ; Logistic Models ; Male ; Middle Aged

AIMTo study the role of oxidative stress in the initiation and development of diabetic neuropathy.

METHODSThe diabetic rats were induced with streptozotocin (STZ). The malondialdehyde (MDA) level, total superoxide dismutase (SOD) and Na(+) -K(+) -ATPase activity were measured in the sciatic nerves at various stages of diabetes. The correlation of the MDA level and Na(+) -K(+) -ATPase activity was analyzed in diabetic rats. The pathological changes of sciatic nerve at diabetic various stages were examined by light microscopy.

RESULTSThe MDA level increased significantly in diabetic sciatic nerves as compared to controls at all time intervals. Total SOD activity increased significantly in diabetic sciatic nerves as compared to controls at one month of diabetes and progressively decreased at three/six months of diabetes. Na(+) -K(+) -ATPase activity progressively decreased at three/six months of diabetes. The correlation analysis indicated that the Na(+) -K(+) -ATPase activity was negative correlation with the MDA level in the diabetic rats. Histopathological study of the diabetic sciatic nerves showed that the pathological changes were observed at 3 months of diabetes, the changes were more serious as the diabetic duration was longer.

CONCLUSIONOxidative stress is found to occur during the early stages of STZ-induced diabetes (no neuropathy) and this state is maintained after initiation of neuropathy. The decreased Na(+) -K(+) -ATPase activity is associated with oxidative stress in the diabetic rats. Therefore, oxidative stress plays an important role in the initiation and development of diabetic neuropathy.

Animals ; Diabetes Mellitus, Experimental ; physiopathology ; Diabetic Neuropathies ; physiopathology ; Male ; Oxidative Stress ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Sciatic Nerve ; enzymology ; Sodium-Potassium-Exchanging ATPase ; metabolism ; Superoxide Dismutase ; metabolism

OBJECTIVES: This study examined the effect of cilostazol, a potent phosphodiesterase inhibitor, on the progression of neuropathies associated with streptozotocin-induced diabetes mellitus in Sprague-Dawley rats. METHODS: Eight weeks after streptozotocin treatment, a pelleted diet containing 0.03% cilostazol (15 mg/kg body weight) was given for four weeks. Body weight, blood glucose level, motor nerve conduction velocity (MNCV), myelinated fiber density and size distribution of sciatic nerves were compared between age-matched normal rats (Group 1), control diabetic rats (Group 2) and cilostazol-treated diabetic rats (Group 3). RESULTS: Body weight was significantly reduced and blood glucose level was significantly increased in diabetic rats (Group 2 and 3) compared to normal rats. MNCV and cAMP content of sciatic nerves were significantly reduced in diabetic rats 12 weeks after streptozotocin treatment. Myelinated fiber size and density were also significantly reduced, and thickening of the capillary walls and duplication of the basement membranes of the endoneural vessels were observed in the diabetic rats. Whereas both body weight and blood glucose level of Group 3 did not differ significantly from those of Group 2, cilostazol treatment significantly increased MNCV and cAMP content of sciatic nerves in Group 3 but not to the levels observed in Group 1. MNCV positively correlated with cAMP content of sciatic nerves (r = 0.86; p < 0.001). Cilostazol treatment not only restored myelinated fiber density and size distribution but reversed some of the vascular abnormalities. CONCLUSION: These findings suggest that a reduced cAMP content in motor nerves may be involved in the development of diabetic neuropathy, and that cilostazol may prevent the progression of diabetic neuropathy by restoring functional impairment and morphological changes of peripheral nerves.
Animal ; Cyclic AMP/metabolism ; Diabetes Mellitus, Experimental/physiopathology ; Diabetes Mellitus, Experimental/drug therapy ; Diabetic Neuropathies/prevention & control* ; Diabetic Neuropathies/physiopathology ; Diabetic Neuropathies/pathology ; Male ; Neural Conduction/drug effects ; Phosphodiesterase Inhibitors/pharmacology* ; Rats ; Rats, Sprague-Dawley ; Sciatic Nerve/physiopathology ; Sciatic Nerve/pathology ; Sciatic Nerve/drug effects ; Tetrazoles/pharmacology*

Diseases of the peripheral nervous system are the most prevalent in patients with end-stage renal disease (ESRD). Although increased blood levels of lead in ESRD have been reported, the role of lead remains to be elucidated. The purpose of this study was to determine the connection of blood lead concentration with peripheral nerve conduction velocity. One hundred ninety-eight healthy subjects (control group) and 68 patients with ESRD undergoing hemodialysis (ESRD group) were enrolled. Nerve conduction was measured within two hours after hemodialysis. Orthodromic sensory nerve action potentials and compound muscle action potentials were recorded on the median, ulnar, and radial nerves. Hemoglobin-corrected blood lead was significantly higher in ESRD patients than in controls (9.1+/-2.8 microgram/dL vs. 5.9+/-2.3 microgram/dL, p<0.001). 32.4% of 68 ESRD patients with diabetes mellitus were significantly related to poorer motor and sensory nerve conduction velocity (p<0.001). However, blood lead was not a significant predictor of the nerve conduction velocity (p>0.05). Our result suggested that even though the blood lead levels were high in ESRD, they were not associated with the decline of peripheral nerve function. Diabetes mellitus is a primary independent risk of neuropathy in ESRD patients.
Peripheral Nervous System Diseases/blood/etiology/physiopathology ; Peripheral Nerves/physiopathology ; Neural Conduction/*physiology ; Middle Aged ; Male ; Lead/*blood/metabolism ; Kidney Failure, Chronic/*blood/complications/*physiopathology ; Humans ; Female ; Diabetic Neuropathies/blood/physiopathology ; Case-Control Studies ; Bone and Bones/metabolism ; Body Burden ; Adult

OBJECTIVETo explore the role of insulin-like growth factor 1 (IGF-1) gene expression abnormality in neurotrophic causes of diabetic peripheral neurophathy.

METHODSDiabetes was induced in Sprague Dawley rats by alloxan. The parameters were measured as follows: IGF-1 mRNA by revere transcriptase-polymer chain reaction (RT-PCR); IGF-1 peptide by enzyme-linked immunosorbent assay (ELISA); electrophysiological parameters of nerves by evoked electromyogram; morphometric evaluation of sciatic nerves under light microscope and transmission electron microscope.

RESULTSDuring early diabetic stage, IGF-1 mRNA [(0.430+/-0.031) vs. (0.370+/-0.016), P<0.01, (0.430+/-0.031) vs. (0.280+/-0.010), P<0.001, respectively], IGF-1 peptide contents [(38.44+/-3.60) ng/mg vs. (30.06+/-2.41) ng/mg, P<0.01, (38.44+/-3.6) ng/mg vs. (3.71+/-2.70) ng/mg P<0.001, respectively] in sciatic nerve tissue reduced in diabetic rats with hyperglycemia and varied with severity of state when compared with non-diabetic control rats, and further gradually down-regulated in the diabetic rats with duration of diabetes [IGF-1 mRNA (0.320+/-0.021) to approximately (0.230+/-0.060); IGF-1 peptide (28.80+/-3.30) to approximately (19.51+/-1.80) ng/mg]. Furthermore, they correlated with nerve functional (sensory nerve conduction velocity: r=0.741, P<0.001; amplitude of evoked potential: r=0.716, P<0.001, respectively) and structural abnormality (axonal area r=0.81, P<0.001) of sciatic nerve. No difference was found in the above parameters between diabetic rats with euglycemia and non-diabetic control group.

CONCLUSIONIGF-1 gene expression in tissues was down-regulated from early diabetic stage, and varied with the severity and duration of diabetic state. The decrement in IGF-1 level might contribute to the initiation and development of diabetic neuropathy via autocrine or paracrine pathway.

Alloxan ; Animals ; Diabetes Mellitus, Experimental ; etiology ; metabolism ; Diabetic Neuropathies ; etiology ; metabolism ; Electrophysiology ; Evoked Potentials ; Insulin-Like Growth Factor I ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; Rats ; Rats, Sprague-Dawley ; Sciatic Nerve ; physiopathology

OBJECTIVETo observe abnormalities in heart rate variability (HRV) in diabetic rats and to explore the effects of treatment with Guizhi Decoction ([symbols; see text]) on cardiac autonomic nervous (CAN) imbalance.

METHODSA radio-telemetry system for monitoring physiological parameters was implanted into rats to record electrocardiac signals and all indictors of HRV [time domain measures: standard deviation of all RR intervals in 24 h (SDNN), root mean square of successive differences (RMSSD), percentage of differences between adjacent RR intervals greater than 50 ms (PNN50), and standard deviation of the averages of RR intervals (SDANN); frequency domain measures: low frequency (LF), high frequency (HF), total power (TP), and LF/HF ratio]. The normal group was randomly selected, and the remaining rats were used to establish streptozocin (STZ)-induced diabetic model. After 4 weeks, the model rats were divided into the model group, the methycobal group, and the Guizhi Decoction group, 9 rats in each group. Four weeks after intragastric administration of the corresponding drugs, the right atria of the rats were collected for immunohistochemical staining of tyrosine hydroxylase (TH) and choline acetyltransferase (CHAT) to observe the distribution of the sympathetic and vagus nerves in the right atrium. The myocardial homogenate from the interventricular septum and the left ventricle was used for determination of TH, CHAT, growth-associated protein 43 (GAP-43), nerve growth factor (NGF), and ciliary neurotrophic factor (CNTF) levels using an enzyme-linked immunosorbent assay.

RESULTS(1) STZ rats had elevated blood glucose levels, reduced body weight, and decreased heart rate; there was no difference between the model group and the drug treated groups. (2) Compared with the model group, only RMSSD and TP increased in the methycobal group significantly (P<0.05); SDNN, RMSSD, PNN50, LF, HF, and TP increased, LF/HF decreased (P<0.05), and SDANN just showed a decreasing trend in the Guizhi Decoction group (P>0.05). TH increased, CHAT decreased, and TH/CHAT increased in the myocardial homogenate of the model group (P<0.05). Compared with the model group, left ventricular TH reduced in the methycobal group; and in the Guizhi Decoction group CHAT increased, while TH and TH/CHAT decreased (P<0.05). Compared with the model group, CNTF in the interventricular septum increased in the methycobal group (P<0.05); GAP-43 increased, NGF decreased, and CNTF increased (P<0.05) in the Guizhi Decoction group. There were significant differences in the reduction of NGF and elevation of CNTF between the Guizhi Decoction group and the methycobal group (P<0.05). (3) Immunohistochemical results showed that TH expression significantly increased and CHAT expression significantly decreased in the myocardia of the model group, whereas TH expression decreased and CHAT expression increased in the Guizhi Decoction group (P<0.05).

CONCLUSIONGuizhi Decoction was effective in improving the function of the vagus nerve, and it could alleviate autonomic nerve damage.

Animals ; Autonomic Nervous System ; drug effects ; physiopathology ; Choline O-Acetyltransferase ; metabolism ; Diabetes Mellitus, Experimental ; drug therapy ; physiopathology ; Diabetic Neuropathies ; drug therapy ; physiopathology ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; Heart ; innervation ; physiopathology ; Heart Rate ; drug effects ; physiology ; Male ; Monitoring, Physiologic ; methods ; Rats, Wistar ; Telemetry ; methods ; Treatment Outcome ; Tyrosine 3-Monooxygenase ; metabolism ; Vagus Nerve ; drug effects ; physiopathology

OBJECTIVETo study the effects of Jinmaitong capsule on oxidative stress and cell apoptosis of dorsal root ganglion (DRG) in rats with diabetic peripheral neuropathy.

METHODSSixty male SD rats were randomly divided into normal group and model groups. The diabetic rat models were established using Streptozotocin (STZ) method (60 mg/kg of intraperitoneal injection), and then randomly divided Jinmaitong low, middle, and high-dose groups and vitamin C group. All the experimental rats were sacrificed at 16-week and then the DRG was isolated. The morphological changes of DRG were observed using the Nissl's staining, and the NADPH oxidase subunit p22-phox, Cyt C, Bcl-2, and Caspase-3 of DRG in rats were detected by immunohistochemistry and quantitative reverse transcription PCR (qRT-PCR). Cell apoptosis was detected by TUNEL.

RESULTSCompared with the model group, the expressions of NADPH oxidase subunit p22-phox protein, Cyt expression of C protein, Caspase-3 protein, and mRNA cell apoptosis rate in each treatment group significantly decreased whereas the expressions of Bcl-2 mRNA and protein significantly increased (P<0.05 or P<0.01). The Jinmaitong high-dose group had the best effect and was significantly different from that of the vitamin C group (P<0.01).

CONCLUSIONSJinmaitong capsule can prevent the nerve injury in rats with diabetic peripheral neuropathy by inhibiting oxidative stress and decreasing the apoptosis. The high-dose Jinmaitong capsule has the best effect and is superior to vitamin C.

Animals ; Apoptosis ; drug effects ; Capsules ; Caspase 3 ; metabolism ; Diabetes Mellitus, Experimental ; Diabetic Neuropathies ; drug therapy ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Ganglia, Spinal ; physiopathology ; Male ; Oxidative Stress ; drug effects ; RNA, Messenger ; Rats ; Rats, Sprague-Dawley

Traditional Chinese medicine has certain effects on diabetic peripheral neuropathy and predominates in the integral medication of multi-factorial, multi-target action, et al. In this paper, the experimental studies concerning the effects of Chinese compound recipes on diabetic peripheral neuropathy in recent 6 years are reviewed in respect of the polyalcohol pathway and related metabolic disorder, the activation of protein kinase C, the formation of advanced glycation endoproducts, oxidative stress, neurotrophy factors, haemodynamics and blood vessel factors. It analyzes the existing problems and looks into the future research in this domain as well.
Animals ; Diabetic Neuropathies ; drug therapy ; metabolism ; physiopathology ; Drugs, Chinese Herbal ; isolation & purification ; therapeutic use ; Enzyme Activation ; drug effects ; Hemodynamics ; drug effects ; Medicine, Chinese Traditional ; methods ; trends ; Neural Conduction ; drug effects ; Oxidative Stress ; drug effects ; Phytotherapy ; methods ; trends ; Protein Kinase C ; metabolism