Nerve growth factor(NGF) is closely ralated to the occurrence and development of diabetic peripheral neuropathy (DPN). Traditional Chinese medicine has certain effects on the promotion of NGF expression. It analyzes the relationship of NGF and DPN and the effects of Traditional Chinese Medicine on them as well as the existing problems and looks into the future research in this domain.
Animals ; Diabetic Neuropathies ; drug therapy ; genetics ; metabolism ; Drugs, Chinese Herbal ; therapeutic use ; Gene Expression ; drug effects ; Humans ; Nerve Growth Factor ; genetics ; metabolism

OBJECTIVETo investigate the relationship between diabetes and somatostatin (SOM).

METHODSWe established a streptozocin-induced diabetic rats model and studied the changes of SOM mRNA in hippocampi of diabetic and normal rats by using in situ hybridication and computer image analysis. We studied the mechanism of chronic diabetes encephalopathy by observing the changes of somatostatin mRNA in the hippocampus of diabetic rats was studied.

RESULTThe number, light density and average area of positive cells in dentate gyrus area of hippocampus in diabetes model were reduced significantly as compared with normal rats (P < 0.01).

CONCLUSIONA decline in SOM mRNA expression may play a role in chronic diabetes encephalopathy because of SOM effect in brain.

Animals ; Brain Diseases ; etiology ; metabolism ; Dentate Gyrus ; metabolism ; Diabetes Mellitus, Experimental ; metabolism ; Diabetic Neuropathies ; metabolism ; Hippocampus ; metabolism ; Male ; RNA, Messenger ; biosynthesis ; Rats ; Rats, Sprague-Dawley ; Somatostatin ; biosynthesis ; genetics

Huanglian Wendan decoction (HLWDD) has been used for the treatment of symptom of "Re", one of major causes in diabetes and metabolic disorders, according to the theory of traditional Chinese medicine. The present study aimed at investigating the cerebral protective effects of HLWDD on diabetic encephalopathy (DE), one of the major diabetic complications. The effects of HLWDD and metformin were analyzed in the streptozocin (STZ) + high-glucose-fat (HGF) diet-induced DE rats by gastric intubation. In the present study, the effects of HLWDD on cognition deficits were investigated after 30-day intervention at two daily dose levels (3 and 6 g·kg). To explore the potential mechanisms underlying the effects of HLWDD, we detected the alterations of neuronal damages, inflammatory cytokines, and impaired insulin signaling pathway in hippocampus of the DE rats. Based on our results from the present study, we concluded that the protective effects of HLWDD against the cognitive deficits and neuronal damages through inhibiting the release of inflammatory cytokines and repairing insulin signaling pathway in hippocampus of the DE rats.
Animals ; Cognition Disorders ; genetics ; metabolism ; prevention & control ; Cytokines ; genetics ; metabolism ; Diabetic Neuropathies ; drug therapy ; genetics ; metabolism ; psychology ; Drugs, Chinese Herbal ; administration & dosage ; Hippocampus ; drug effects ; metabolism ; Humans ; Insulin ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo screen and identify differentially expressed genes in the dorsal root ganglion (DRG) in early experimental diabetic rats.

METHODSDiabetic model rats were induced by single intraperitoneal injection of streptozotocin (STZ). At the second week after STZ injection, the sensory nerve conduction velocities (SNCV) of sciatic nerve were measured as an indicator of neuropathy. The technique of silver-staining mRNA differential display polymerase chain reaction (DD-PCR) was used to detect the levels of differentially expressed genes in rat DRG. The cDNA fragments that displayed differentially were identified by reverse-hybridization, cloned and sequenced subsequently, and then confirmed by Northern blot.

RESULTSThe SNCV in the diabetic model group [n = 9, (45.25+/-10.38) m/s] reduced obviously compared with the control group [n = 8, (60.10+/-11.92) m/s] (P < 0.05). Seven distinct cDNA clones, one was up-regulated gene and the others were down-regulated ones, were isolated by silver-staining mRNA differential display method and confirmed by Northern blot. According to the results of sequence alignment with GenBank data, majority of the clones had no significant sequence similarity to previously reported genes except only one that showed high homology to 6-pyruvoyl-tetrahydropterin synthase mRNA (accession No. BC059140), which had not been reported to relate to diabetic neuropathy.

CONCLUSIONThese differentially expressed genes in the diabetic DRG may contribute to the pathogenesis of diabetic peripheral neuropathy.

Animals ; Blotting, Northern ; Diabetes Mellitus, Experimental ; genetics ; physiopathology ; Diabetic Neuropathies ; genetics ; physiopathology ; Ganglia, Spinal ; physiopathology ; Gene Expression ; Gene Expression Profiling ; Male ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Sciatic Nerve ; physiopathology

OBJECTIVE: To evaluate the effect of hepatic insulin gene therapy on diabetic enteric neuropathy. METHODS: Mice were randomly allocated into 3 groups: a normal control group, a diabetic group, and a diabetic gene therapy group. Diabetes were induced by penial vein injection of streptozocin (STZ). The gene therapy group received hepatic insulin gene therapy while the other 2 groups only received an empty virus expressing green fluorescent protein. Random blood glucose, body weight growth, gastric emptying, total bowel length, absolute and relative bowel transit, electric field stimulation of colon smooth muscle, colon nuclei staining and counting were measured. RESULTS: We successully established a mouse model of diabetic enteric neuropathy which manifests as: 8 weeks of continuous hyperglycemia,increased total bowel length, decreased relative bowel transit, impaired colon smooth muscle relaxation and loss of inhibitory neurons in colon. Through gene therapy, the above indexes were normalized or ameliorated, suggesting hepatic insulin gene therapy is capable of preventing diabetic enteric neuropathy. CONCLUSION Hepatic insulin gene therapy can prevent STZ induced diabetic enteric neuropathy.
Adenoviridae ; Animals ; Diabetes Mellitus, Experimental ; complications ; therapy ; Diabetic Neuropathies ; therapy ; Enteric Nervous System ; metabolism ; pathology ; Gastrointestinal Diseases ; etiology ; therapy ; Gene Transfer Techniques ; Genetic Therapy ; Genetic Vectors ; Hepatocytes ; metabolism ; Insulin ; genetics ; metabolism ; Mice ; Proinsulin ; genetics

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

To explore the role of vascular endothelial growth factor (VEGF) in diabetic peripheral neuropathic pain in rats.
 Methods: Twenty-four adult male Sprague-Dawley rats aged 8 weeks were randomly divided into 3 groups (n=8 per group). The control group (C group): rats were intraperitoneally injected with sodium citrate solution at 10 mL/kg; the model group (M group): rats were intraperitoneally injected with streptozotocin at 65 mg/kg; the treatment group (T group): rats received intraperitoneal injection of anti-VEGF antibody (10 mg/kg) at the 1st, 3rd, 7th, 10th day after STZ treatment. Meanwhile, rats of C and M group were received with the same volume of sodium citrate solution. Blood glucose was measured before 1 day or at the 1st, 3rd, 7th or 14th day after receiving STZ. Body weight, paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) were measured before 1 day or at the 1st, 3rd, 5th, 7th, 10th or 14th day after receiving STZ. All lumbar spinal cords were dissected to examine the p-protein kinase B (p-Akt) and transient receptor potential vanilloid 1 (TRPV1) expression by Western blot.
 Results: After injection with STZ, the body weight showed significant differences at some time point between the M, T or C group (P<0.01); body weight of rat in the C group were increased gradually. Compared with the C group, the fast blood glucose in the M or the T Group at the same time points were increased significantly (P<0.01). The PWMT and PWTL of the M, T or C group were significant difference among various time points (P<0.01). The PWMT and PWTL in the M or T group were obviously reduced compared with those in the C group (P<0.01). Compared with the M group, the PWMT and PWTL in the T group were increased at the 10th or 14th day (P<0.01 or P<0.05). Compared with the C group, the p-Akt and TRPV1 levels in the M and T group were increased (P<0.01). Compared with the M group, p-Akt and TRPV1 levels in T group were decreased (P<0.01).
 Conclusion: VEGF is able to regulate the expression of TRPV1 through PI3K/Akt pathway, which contributes to diabetic peripheral neuropathic pain in rats. Anti-VEGF treatment may be useful for alleviation of diabetic peripheral neuropathic pain.
Animals ; Antibodies ; pharmacology ; therapeutic use ; Diabetes Mellitus, Experimental ; chemically induced ; Diabetic Neuropathies ; chemically induced ; drug therapy ; Gene Expression Regulation ; drug effects ; Male ; Phosphatidylinositol 3-Kinases ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; TRPV Cation Channels ; genetics ; Vascular Endothelial Growth Factor A ; metabolism

This study investigated the effect of Lianmei Qiwu Decoction(LMQWD) on the improvement of cardiac autonomic nerve remodeling in the diabetic rat model induced by the high-fat diet and explored the underlying mechanism of LMQWD through the AMP-activated protein kinase(AMPK)/tropomyosin receptor kinase A(TrkA)/transient receptor potential melastatin 7(TRPM7) signaling pathway. The diabetic rats were randomly divided into a model group, an LMQWD group, an AMPK agonist group, an unloaded TRPM7 adenovirus group(TRPM7-N), an overexpressed TRPM7 adenovirus group(TRPM7), an LMQWD + unloaded TRPM7 adenovirus group(LMQWD+TRPM7-N), an LMQWD + overexpressed TRPM7 adenovirus group(LMQWD+TRPM7), and a TRPM7 channel inhibitor group(TRPM7 inhibitor). After four weeks of treatment, programmed electrical stimulation(PES) was employed to detect the arrhythmia susceptibility of rats. The myocardial cell structure and myocardial tissue fibrosis of myocardial and ganglion samples in diabetic rats were observed by hematoxylin-eosin(HE) staining and Masson staining. The immunohistochemistry, immunofluorescence, real-time quantitative polymerase chain reaction(RT-PCR), and Western blot were adopted to detect the distribution and expression of TRPM7, tyrosine hydroxylase(TH), choline acetyltransferase(ChAT), growth associated protein-43(GAP-43), nerve growth factor(NGF), p-AMPK/AMPK, and other genes and related neural markers. The results showed that LMQWD could significantly reduce the arrhythmia susceptibility and the degree of fibrosis in myocardial tissues, decrease the levels of TH, ChAT, and GAP-43 in the myocardium and ganglion, increase NGF, inhibit the expression of TRPM7, and up-regulate p-AMPK/AMPK and p-TrkA/TrkA levels. This study indicated that LMQWD could attenuate cardiac autonomic nerve remodeling in the diabetic state, and its mechanism was associated with the activation of AMPK, further phosphorylation of TrkA, and inhibition of TRPM7 expression.
Rats ; Animals ; AMP-Activated Protein Kinases/metabolism* ; Nerve Growth Factor/metabolism* ; Diabetes Mellitus, Experimental/drug therapy* ; TRPM Cation Channels/metabolism* ; GAP-43 Protein/metabolism* ; Signal Transduction ; Diabetic Neuropathies/genetics* ; Fibrosis

OBJECTIVE: To investigate the effect of xiaokeling concentration fluid on insulin-like growth factor-1 (IGF-1) mRNA expression in sciatic nerve of Streptozotocin-induced diabetic rats. METHODS: Thirty diabetic rats were randomly divided into model group, mecobalamin tablets group, and xiaokeling concentration fluid group. The IGF-1 mRNA level in sciatic nerve of each group was determined after 8 weeks by relative quantity RT-PCR. RESULTS: The IGF-1 mRNA level in sciatic nerve of diabetic rats between xiaokeling concentration fluid group, mecobalamin tablets group and normal group showed no significant difference ( P = 0.213, P = 0.822, P = 0.304 ), while was significantly higher than that of the model group ( P < 0.05 ). IGF-1 mRNA level was negatively correlated with the level of blood sugar (P < 0.05). CONCLUSION IGF-1 mRNA level decreased in sciatic nerve of diabetic rats. Xiaokeling concentration fluid can increase the IGF-1 mRNA level in sciatic nerve of diabetic rats. Xiaokeling concentration fluid is involved in the regulation of IGF-1 expression, and probably prevents diabetic peripheral neuropathy from deteriorating.
Animals ; Diabetes Mellitus, Experimental ; drug therapy ; metabolism ; Diabetic Neuropathies ; prevention & control ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Hypoglycemic Agents ; pharmacology ; therapeutic use ; Insulin-Like Growth Factor I ; biosynthesis ; genetics ; Male ; RNA, Messenger ; biosynthesis ; genetics ; Random Allocation ; Rats ; Receptor, IGF Type 1 ; Reverse Transcriptase Polymerase Chain Reaction ; Sciatic Nerve ; metabolism

Neuropathic pain is one of the common complications of diabetes. Tetrahydropalmatine(THP) is a main active component of Corydalis Rhizoma with excellent anti-inflammatory and pain-alleviating properties. This study aims to investigate the therapeutic effect of THP on diabetic neuropathic pain(DNP) and the underlying mechanism. High-fat and high-sugar diet(4 weeks) and streptozotocin(STZ, 35 mg·kg~(-1), single intraperitoneal injection) were employed to induce type-2 DNP in rats. Moreover, lipopolysaccharide(LPS) was used to induce the activation of BV2 microglia in vitro to establish an inflammatory cellular model. Fasting blood glucose(FBG) was measured by a blood glucose meter. Mechanical withdrawal threshold(MWT) was assessed with von Frey filaments, and thermal withdrawal latency(TWL) with hot plate apparatus. The protein expression levels of OX42, inducible nitric oxide synthase(iNOS), CD206, p38, and p-p38 were determined by Western blot, the fluorescence expression levels of OX42 and p-p38 in the dorsal horn of the rat spinal cord by immunofluorescence, the mRNA content of p38 and OX42 in rat spinal cord tissue by qRT-PCR, and levels of nitric oxide(NO), interleukin-1β(IL-1β), interleukin-6(IL-6), tumor necrosis factor-α(TNF-α), interleukin-10(IL-10), and serum fasting insulin(FINS) by enzyme-linked immunosorbent assay(ELISA). RESULTS:: showed that the mo-del group demonstrated significant decrease in MWT and TWL, with pain symptoms. THP significantly improved the MWT and TWL of DNP rats, inhibited the activation of microglia and p38 MAPK signaling pathway in rat spinal cord, and ameliorated its inflammatory response. Meanwhile, THP promoted the change of LPS-induced BV2 microglia from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype, suppressed the activation of the p38 MAPK signaling pathway, decreased the expression levels of inflammatory factors NO, IL-1β, IL-6, and TNF-α, and increased the expression level of anti-inflammatory factor IL-10. The findings suggested that THP can significantly ameliorate the pain symptoms of DNP rats possibly by inhibiting the inflammatory response caused by M1 polarization of microglia via the p38 MAPK pathway.
Animals ; Berberine Alkaloids ; Blood Glucose/metabolism* ; Diabetes Mellitus ; Diabetic Neuropathies/genetics* ; Interleukin-10 ; Interleukin-6/metabolism* ; Lipopolysaccharides/pharmacology* ; Microglia ; Neuralgia/metabolism* ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Spinal Cord/metabolism* ; Streptozocin/therapeutic use* ; Tumor Necrosis Factor-alpha/metabolism* ; p38 Mitogen-Activated Protein Kinases/metabolism*