[Systematic review and Meta-analysis of efficacy and safety of Tangmaikang Granules in treatment of diabetic peripheral neuropathy].

This study aimed to explore the efficacy and safety of Tangmaikang Granules in the treatment of diabetic peripheral neuropathy(DPN). PubMed, Cochrane Library, EMbase, SinoMed, CNKI, Wanfang and VIP were retrieved for randomized controlled trial(RCT) of Tangmaikang Granules in the treatment of DPN. Cochrane handbook 5.3 was used to evaluate the quality of the inclu-ded studies, and RevMan 5.4.1 and Stata 15.1 were employed to analyze data and test heterogeneity. GRADEpro was used to assess the quality of each outcome index. Clinical effective rate was the major outcome index, while the improvement in numbness of hands and feet, pain of extremities, sluggishness or regression of sensation, sensory conduction velocity(SCV) and motor conduction velocity(MCV) of median nerve and peroneal nerve, fasting blood glucose(FBG), 2 h postprandial blood glucose(2hPBG), and glycated hemoglobin(HbA1c) and incidence of adverse reactions were considered as the minor outcome indexes. A total of 19 RCTs with 1 602 patients were eventually included. The Meta-analysis showed that the improvements in clinical effective rate(RR=1.45, 95%CI[1.32, 1.61], P<0.000 01), pain of extremities(RR=1.70, 95%CI[1.27, 2.27], P=0.000 3), MCV of peroneal nerve(MD=4.08, 95%CI[3.29, 4.86], P<0.000 01) and HbA1c(SMD=-1.23, 95%CI[-1.80,-0.66], P<0.000 1) of Tangmaikang Granules alone or in combination in the experimental group were better than those in the control group. Compared with the conditions in the control group, numbness of hands and feet(RR=1.42, 95%CI[1.12, 1.80], P=0.003), sluggishness or regression of sensation(RR=1.41, 95%CI[1.05, 1.91], P=0.02), SCV of median nerve(MD=4.59, 95%CI[0.92, 8.27], P=0.01), SCV of peroneal nerve(MD=4.68, 95%CI[3.76, 5.60], P<0.000 01) and MCV of median nerve(MD=5.58, 95%CI[4.05, 7.11], P<0.000 01) of Tangmaikang Granules in combination in the experimental group were improved by subgroup analysis. The levels of FBG(MD=-0.57, 95%CI[-1.27, 0.12], P=0.11) and 2hPBG(MD=-0.69, 95%CI[-1.70, 0.33], P=0.18) in the experimental group were similar to those in the control group after treatment with Tangmaikang Granules alone or in combination. There was no difference in the safety(RR=1.28, 95%CI[0.58, 2.82], P=0.54) of Tangmaikang Granules in the treatment of DPN between the experimental group and the control group. Tangmaikang Granules could significantly increase clinical effective rate and nerve conduction velocity as well as improve symptoms of peripheral nerve and blood glucose level, and no serious adverse reactions were identified yet. Further validation was needed in future in large-sample, multicenter, high-quality RCTs.

Diabetic Neuropathy: a Critical, Narrative Review of Published Data from 2019.

PURPOSE OF REVIEW: This manuscript is a systematic, narrative review that compiles and describes all data available from 2019 related to epidemiologic, diagnostic, and therapeutic advances in diabetic neuropathy (DN). RECENT FINDINGS: Epidemiology of DN is discussed. Diagnostic modalities include predictive models, electrodiagnostics, imaging, and biomarkers. A majority of studies on the treatment of diabetic peripheral neuropathy (DPN) involve pharmacotherapy, but complementary and alternative medicine, exercise, modalities, psychological, interventional, and surgical options are also explored. DN is a highly prevalent and debilitating consequence of diabetes that can present challenges to the clinician as the assessment is largely subjective with different phenotypic presentations among patients. Treatment of DN is largely symptomatic as the pathogenesis of DN is not fully understood and is likely multifactorial. It is evident from the broad range of treatments that too often provide unsatisfactory relief that there is no consensus about a single most effective treatment for DN, and monotherapy rarely proves to be successful.

Traditional Chinese medicine fumigation as auxiliary treatment of diabetic peripheral neuropathy: A protocol for systematic review and meta-analysis.

BACKGROUND: Diabetic peripheral neuropathy (DPN) is 1 of the most common clinical complications of diabetes, which seriously affects the quality of life of patients and causes a substantial economic burden on diabetes care. The pathogenesis of DPN is complex. There is no targeted treatment method, and mainstream treatment methods have low efficacy and large side effects. Traditional Chinese medicine has rich clinical experience in the prevention and treatment of diabetic peripheral neuropathy, which has dramatically improved the quality of life of patients. It is clinically proven that traditional Chinese medicine fumigants (TCMF) have apparent effects in treating diabetic peripheral neuropathy. Therefore, we aim to systematically review the effectiveness and safety of TCMF for DPN. METHODS: We will search the following databases: PubMed, Embase, Cochrane Library, MEDLINE, the China National Knowledge Infrastructure, the Chinese Biomedical Literature Database, Cqvip Database, and Wanfang Data. Besides, we will also search for clinical trial registrations, potential grey literature, relevant conference abstracts, and reference lists of established studies. The studies published from the inception of the database to November 2020 will be retrieved. The randomized controlled trials on TCMF for DPN will be included. Also, we will search for clinical trial registrations, potential grey literature, relevant conference abstracts, and reference lists of established studies. The main result is clinical efficacy and nerve conduction velocity. Fasting blood glucose, 2 hours postprandial blood glucose, blood lipid, glycosylated hemoglobin, and adverse events are secondary results. We will perform the analyses using RevMan V.5.3 software. RESULTS: This study will provide a high-quality comprehensive evaluation of the efficacy and safety of TCMF in the treatment of DPN. CONCLUSIONS: This systematic review will evaluate the effectiveness and safety of TCMF in the treatment of DPN, and provide the latest evidence for clinical application. INPLASY REGISTRATION NUMBER: INPLASY2020110137.

Effect of photobiomodulation on serum neuron specific enolase (NSE) among patients with diabetic peripheral neuropathy - A pilot study.

BACKGROUND AND AIM: Photobiomodulation is an emerging therapy for Diabetic peripheral neuropathy (DPN) of which the management is still a dilemma for clinicians. Elevated Neuron Specific Enolase (NSE) is associated with neuropathy. We aimed this study to assess the effect of Low Level Laser Therapy (LLLT) on Serum Neuron Specific Enolase in Type II Diabetes Mellitus patients with DPN. METHODOLOGY: Pre post interventional study was done on 50 patients with DPN. DPN was confirmed using 10g Monofilament test, Vibration perception threshold (VPT) and Michigan Neuropathy Screening Instrument. All patients were provided with LLLT for 9 min on dorsal and plantar of foot with a dosage of 3.1 J/cm 2 for 10 days. A blood sample was collected at baseline and 4 weeks after LLLT for NSE estimation. RESULT: A significant reduction in serum NSE levels (0.006) after 4 weeks of laser therapy was observed in 42 patients when compared with baseline. A significant reduction in the vibration perception threshold (p = 0.003) and Numeric pain rating scale (p = 0.004) were observed. CONCLUSION: In this pilot study, we have assessed the effect of LLLT on serum NSE levels among patients with DPN and showed improved quality of life and decrease in serum NSE levels. These findings should be investigated in larger trials.

The Effects of Tocotrienol-Rich Vitamin E (Tocovid) on Diabetic Neuropathy: A Phase II Randomized Controlled Trial.

Chronic hyperglycemia increases oxidative stress, activates inflammatory pathways and reduces nerve growth factor (NGF) among diabetic patients, which contribute to development of diabetic peripheral neuropathy (DPN). Tocotrienol-Rich Vitamin E (Tocovid) possesses potent antioxidant and anti-inflammatory properties which are postulated to target these pathogeneses in order to ameliorate DPN. This study aims to evaluate the effects of Tocovid on nerve conduction parameters and serum biomarkers among diabetic patients. This multicenter, prospective, randomized, double-blind, placebo-controlled clinical trial was conducted on 80 eligible participants. The intervention group (n = 39) was randomly allocated to receive 200 mg of Tocovid twice a day, and the control group (n = 41) received placebo twice a day. At the end of eight weeks, the nerve conduction parameters, as assessed by nerve conduction study, as well as serum biomarkers (NGF, malondialdehyde, vascular cell adhesion molecule 1, tumor necrosis factor receptor 1 and thromboxane B2) were compared between the two groups. Compared to placebo, Tocovid significantly improves the nerve conduction velocities of all nerves (+1.25 m/s, interquartile range [IQR] 3.35, p < 0.001, median nerve; +1.60 m/s, IQR 1.80, p < 0.001, sural nerve; +0.75 m/s, IQR 2.25, p < 0.001, tibial nerve). Meanwhile, the levels of serum NGF were significantly higher in the Tocovid group as compared to placebo at eight weeks post-intervention. Participants receiving Tocovid illustrated highly significant improvement in terms of nerve conduction velocities for all nerves tested after eight weeks of supplementation. In addition, Tocovid supplementation elevated the levels of serum NGF, in which its increase is postulated to reflect enhanced neuronal functions. This novel finding suggests that Tocovid could be a disease-modifying agent targeting serum NGF to improve nerve conduction velocities.

Cortex Mori Radicis extract promotes neurite outgrowth in diabetic rats by activating PI3K/AKT signaling and inhibiting Ca2+ influx associated with the upregulation of transient receptor potential canonical channel 1.

Cortex Mori Radicis extract (CMR) has various pharmacological properties, such as anti­inflammatory, anti­allergic and anti­hyperglycemic effects. However, the effects and mechanisms of CMR in the neuroregeneration of diabetic peripheral neuropathy (DPN) are unclear. In the present study, the effects of CMR on neurite outgrowth of dorsal root ganglia (DRG) neurons in diabetic rats were investigated and its underlying mechanisms were explored. SD rats were subjected to a high­fat diet with low­dose streptozotocin to induce a Type II diabetes model with peripheral neuropathy. CMR was then applied for four weeks continuously with or without injection of small interfere (si)RNA targeting the transient receptor potential canonical channel 1 (TRPC1) via the tail vein. Blood glucose levels, the number of Nissl bodies, neurite outgrowth and growth cone turning in DRG neurons were evaluated. The expression of TRPC1 protein, Ca2+ influx and activation of the PI3K/AKT signaling pathway were also investigated. The results of the present study showed that CMR significantly lowered blood glucose levels, reversed the loss of Nissl bodies, induced neurite outgrowth and restored the response of the growth cone of DRG neurons in diabetic rats. CMR exerted neurite outgrowth­promoting effects by increasing TRPC1 expression, reducing Ca2+ influx and enhancing AKT phosphorylation. siRNA targeting TRPC1 in the CMR group abrogated its anti­diabetic and neuroregenerative effects, suggesting the involvement of TRPC1 in the biological effects of CMR on DPN.

Effect of Low Level Laser Therapy on serum vitamin D and magnesium levels in patients with diabetic peripheral neuropathy - A pilot study.

BACKGROUND: Diabetic Peripheral neuropathy (DPN) is the most distressing complication of diabetic population leading to loss of sensation, pain, and amputation. Low-level laser therapy (LLLT) has been used to manage nerve injuries as it holds the potential to induce a biostimulatory effect with no side effects. Hence we planned to study the biochemical effect and therapeutic outcomes of LLLT on patients with painful diabetic peripheral neuropathy as a preliminary work. MATERIALS AND METHODS: Pre-posttest analysis was done on 40 patients diagnosed with DPN confirmed using 10 g Monofilament test and Michigan Neuropathy Screening Instrument (MNSI). Vibration sensation and pain measured by Vibration perception threshold (VPT) and Numeric pain rating scale (NPRS). All patients were given LLLT (3.1 J/cm2) on plantar and dorsal of the foot for 10 days. Serum samples were collected at baseline and 4 weeks after LLLT to estimate Vitamin D and Magnesium and compared the results. RESULTS: There was a significant increase in Vitamin D and Magnesium levels after LLLT. We observed a considerable improvement in the quality of life after LLLT demonstrated by a decrease in VPT and MNSI and a reduction in NPRS in DPN patients. CONCLUSION: In this study, we found that LLLT improved the QL and hence may be a useful therapeutic option in treating peripheral neuropathic pain in type 2 diabetic patients. The progress in the serum Magnesium and Vit. D levels were proportional to the QL and may be a good indicator of the prognosis of DPN after LLLT.

Effect of folic acid supplementation on nerve conduction velocity in diabetic polyneuropathy patients.

OBJECTIVES: In diabetic polyneuropathy (DPN) patients, the effect of folic acid and homocysteine has been related to components of nerve conduction velocity (NCV). The objective of this study was to determine the effect of folic acid supplementation on NCV in DPN patients. METHODS: Patients were randomized to receive either 1 mg of folic acid (n = 40) or placebo (n = 40) for 16 weeks. Blood samples were collected to assess serum folic acid and homocysteine concentrations, and NCV was performed for assessment of diabetic neuropathy. RESULTS: At 16 weeks, in the supplemented group, serum levels of folic acid (p < 0.001) increased, homocysteine concentrations decreased (p < 0.001), with no change in serum vitamin B12 levels. There was a significant increase in sensory sural amplitude (p < 0.001), and components of motor nerves, including amplitude (p = 0.001) and velocity (p < 0.001), but decreased onset latency of peroneal (p = 0.019) and tibial (p = 0.011) motor nerves. CONCLUSION: Our data suggest that supplementation with 1 mg of folic acid for 16 weeks may be useful for enhancing NCV in DPN patients.

Dose vitamin D supplementations improve peripheral diabetic neuropathy? A before-after clinical trial.

OBJECTIVE: Peripheral neuropathy is a common complication of diabetes mellitus. This study was set to assess the effect of vitamin D supplementation on peripheral neuropathy in patients with type 2 diabetes (T2DM). MATERIALS AND METHODS: This study was a quasi-experimental trial in Yazd diabetic research center. Sixty T2DM subjects (30-65 years old) with painful diabetic neuropathy enrolled in this study from March 2017 till April 2018. Patients received weekly 50000 IU of vitamin D3 for 12 weeks orally. Evaluation of diabetic neuropathy was performed by using Michigan Neuropathy Screening Instrument (MNSI) before and after trial. Also fasting plasma glucose, HbA1c, calcium and vitamin D checked before and after the trial. SPSS version 20 software was used for statistical analysis. P ≤ 0.05 was considered to be statistically significant. RESULTS: Among 60 T2DM patients, 58 completed the study. Most of them (53.4%) were male. At the end of study, HbA1c, vitamin D, MNSI (both questionnaire and physical examination) improved that is statistically significant (p-value: <0.001). CONCLUSION: Oral supplementation of vitamin D 3 (50,000 IU) once weekly for 12 weeks was associated with improvement in the serum level of vitamin D and significant decrease in the symptoms and sign of diabetic neuropathy. So serum vitamin D level should be checked in persons with diabetic neuropathy and low levels of it should be corrected in order to reducing neuropathy severity.

Auricular vagus nerve stimulation enhances central serotonergic function and inhibits diabetic neuropathy development in Zucker fatty rats.

Painful neuropathy is a frequent comorbidity in diabetes. Zucker diabetic fatty (fa/fa) rats develop type 2 diabetes spontaneously with aging and show nociceptive hypersensitivity at the age of 13 weeks. In preclinical and clinical studies, the treatment of diabetic neuropathy is challenging, but complementary medicine such as transcutaneous auricular vagus nerve stimulation (taVNS) appears beneficial to the relief of neuropathic pain. However, the mechanism behind the effectiveness of taVNS remains unclear. In this study, we show that daily 30-min taVNS (2/15 Hz, 2 mA) for consecutive 27 days effectively inhibited the development of nociceptive hypersensitivity in Zucker diabetic fatty rats as detected by thermal hyperalgesia and mechanical allodynia in hindpaw. We also demonstrated that this beneficial effect in nociceptive behavior is related to an elevated serotonin (5-HT) plasma concentration and an upregulated expression of 5-HT receptor type 1A (5-HT1AR) in hypothalamus. We conclude that daily 30-min taVNS sessions lessen diabetic neuropathy development by enhancing serotonergic function in genetically diabetes prone individuals. Perspective This article presents taVNS as a new approach to inhibit the development of diabetic neuropathy in genetically prone individuals. This approach could potentially help clinicians who seek to avoid the complication of neuropathic pain in diabetic patient or to relieve the pain if there was one.

Text Messaging to Improve Disease Management in Patients With Painful Diabetic Peripheral Neuropathy.

Purpose The purpose of the study was to determine the impact of educational text messages on diabetes self-management activities and outcomes in patients with painful diabetic peripheral neuropathy (pDPN). Methods Patients with pDPN identified from a large integrated health system who agreed to participate were randomized to 6 months of usual care (UC) or UC plus twice-daily diabetes self-management text messages (UC+TxtM). Outcomes included the Pain Numerical Rating Scale, Summary of Diabetes Self-Care Activities (SDSCA), questions on diabetes health beliefs, and glycated hemoglobin (A1C). Changes from baseline were evaluated at 6 months and compared between groups. Results Demographic characteristics were balanced between groups (N = 62; 53% female, mean age = 63 years, 94% type 2 diabetes), as were baseline measures. After 6 months, pain decreased with UC+TxtM from 6.3 to 5.5 and with UC from 6.5 to 6.0, with no difference between groups. UC+TxtM but not UC was associated with significant improvements from baseline on all SDSCA subscales. On diabetes health beliefs, UC+TxtM patients reported significantly increased benefits and reduced barriers and susceptibility relative to UC at 6 months. A1C declined in both groups, but neither change was significant relative to baseline. Conclusions Patients with pDPN who receive twice-daily text messages regarding diabetes management reported reduced pain relative to baseline, although this change was not significant compared with usual care. In addition, text messaging was associated with increased self-management activities and improved diabetes health beliefs and total self-care. These results warrant further investigation.

Levetiracetam synergizes with gabapentin, pregabalin, duloxetine and selected antioxidants in a mouse diabetic painful neuropathy model.

RATIONALE: We have reported that levetiracetam, a novel anticonvulsant with analgesic properties, synergizes with ibuprofen/aspirin/paracetamol in a model of diabetic painful neuropathy (DPN). Most guidelines recommend gabapentin, pregabalin, and duloxetine as first- or second-line agents for DPN. OBJECTIVE: We examined the effects of combination treatment of first-/second-line analgesics with levetiracetam in a model of DPN. Additionally, the levetiracetam's combinations with antioxidants, low dose of aspirin, coenzyme Q10, or α-lipoic acid were evaluated. METHODS: Diabetes was induced in C57BL/6 mice with a single high dose of streptozotocin. The antinociceptive effects of orally administered levetiracetam, gabapentin, pregabalin, duloxetine (acute treatment) and aspirin, coenzyme Q10, and α-lipoic acid (preventive 7-day treatment), as well as combinations of levetiracetam with individual drugs were examined in the tail-flick test. In combination experiments, the drugs were coadministered in fixed-dose fractions of single-drug ED50; the type of interaction was determined by isobolographic analysis. RESULTS: About 60-, 32-, 30-, 26-, 18-, and 6-fold reductions of doses of both drugs in levetiracetam combinations with pregabalin, gabapentin, coenzyme Q10, aspirin, duloxetine, and α-lipoic acid, respectively, were detected. CONCLUSIONS: Combinations of levetiracetam with gabapentin/pregabalin/duloxetine that target different mechanisms/sites of action involved in DPN, as well as combinations of levetiracetam and low-dose aspirin/coenzyme Q10/α-lipoic acid that target underlying causes of DPN, produce marked synergistic interactions in reducing nociception in diabetic mice. This suggests that these combination treatments might be of great benefit for diabetic patients and should be explored further in clinical trials.

Variability of fasting plasma glucose increased risks of diabetic polyneuropathy in T2DM.

OBJECTIVE: To examine whether variations in fasting plasma glucose (FPG), as measured by the coefficient of variation (CV), is a predictor of diabetic polyneuropathy (DPN) risk, considering glycated hemoglobin (HbA1c) and other traditional risk factors. METHODS: Type 2 diabetic patients enrolled in the National Diabetes Care Management Program were ≥30 years of age and free of DPN (n = 36,152). They were enrolled in 2002-2004 and were monitored until 2011. The related factors were analyzed using Cox proportional hazards regression models. RESULTS: During an average 7.23 years of follow-up, a total of 7,219 incident cases of DPN were identified, with a crude incidence rate of 27.62/1,000 person-years (25.83 for men and 29.31 for women). After multivariate adjustment, both FPG-CV and HbA1c were significant predictors of DPN, with corresponding hazard ratios of 1.14 (95% confidence interval [CI] 1.05-1.23) and 1.15 (95% CI 1.06-1.24) for FPG-CV in the fourth to fifth quintiles and 1.13 (95% CI 1.07-1.20) for HbA1c ≥7%. This finding maintained consistency after excluding potential confounders in the sensitivity analysis, further validating the results. CONCLUSIONS: FPG-CV and HbA1c ≥7% were potent predictors of DPN in type 2 diabetic patients. The associations among HbA1c, glycemic variability, and DPN suggest a linked pathophysiologic mechanism, which may play a crucial role in clinical risk assessments.

Garcinia kola aqueous suspension prevents cerebellar neurodegeneration in long-term diabetic rat - a type 1 diabetes mellitus model.

ETHNOPHARMACOLOGICAL RELEVANCE: The development of compounds able to improve metabolic syndrome and mitigate complications caused by inappropriate glycemic control in type 1 diabetes mellitus is challenging. The medicinal plant with established hypoglycemic properties Garcinia kola Heckel might have the potential to mitigate diabetes mellitus metabolic syndrome and complications. AIM OF THE STUDY: We have investigated the neuroprotective properties of a suspension of G. kola seeds in long-term type 1 diabetes mellitus rat model. MATERIALS AND METHODS: Wistar rats, made diabetic by single injection of streptozotocin were monitored for 8 months. Then, they were administered with distilled water or G. kola oral aqueous suspension daily for 30 days. Body weight and glycemia were determined before and after treatment. After sacrifice, cerebella were dissected out and processed for stereological quantification of Purkinje cells. Histopathological and immunohistochemical analyses of markers of neuroinflammation and neurodegeneration were performed. RESULTS: Purkinje cell counts were significantly increased, and histopathological signs of apoptosis and neuroinflammation decreased, in diabetic animals treated with G. kola compared to diabetic rats given distilled water. Glycemia was also markedly improved and body weight restored to non-diabetic control values, following G. kola treatment. CONCLUSIONS: These results suggest that G. kola treatment improved the general condition of long-term diabetic rats and protected Purkinje cells partly by improving the systemic glycemia and mitigating neuroinflammation.

Effect of hyperbaric oxygen on lipoprotein subfractions in diabetic patients.

OBJECTIVES: Favorable metabolic changes have been observed in many in vitro and animal studies after application of hyperbaric oxygen (HBO2). Metabolic changes after hyperbaric oxygen therapy, especially focused on lipoprotein subfractions, have not been described in humans. Our aim was to investigate possible alteration in concentration of lipoprotein subfractions in diabetic patients after hyperbaric oxygen therapy. METHODS: 58 Type 2 diabetic patients were enrolled in a prospective matched case-control study. A total of 31 underwent hyperbaric oxygen therapy, and 27 were included in the control group without HBO2 exposure. Fasting concentrations of lipoprotein subfractions were measured by electrophoresis in polyacrylamide gel 24 hours before and 24 hours after hyperbaric sessions performed at 2.5 atmospheres absolute for 15 days. Homeostatic model assessment of insulin resistance, C-peptide and glycemic variability were assessed before and after therapy. RESULTS: We observed decreased subfractions of very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL 3), LDL 1, LDL 2 and LDL 3-7 after hyperbaric oxygen treatment. In addition, the IDL 1 subfraction, as well as the concentration of C-peptide, increased significantly in the treatment arm. Glycemic variability improved after therapy. No differences were observed in the control group. CONCLUSION: Hyperbaric oxygen therapy is connected with antiatherogenic metabolic changes. This study demonstrates that hyperbaric oxygen therapy may hold potential for inducing metabolic changes in diabetic patients that may decrease their cardiovascular risk.

Clinical efficacy of different doses of lipo-prostaglandin E1 in the treatment of painful diabetic peripheral neuropathy.

OBJECTIVE: To observe the clinical efficacy of different doses of alprostadil (lipo-prostaglandin E1, lipo-PGE1) in the treatment of painful diabetic peripheral neuropathy (DPN). METHODS: Sixty patients with painful DPN were equally and randomly assigned into three groups. Two groups received different doses of lipo-PGE1 by intravenous drip injection (A group: low-dose lipo-PGE1; B group: high-dose lipo-PGE1) following intravenous bolus injection of mecobalamin (MeCbl, 0.5mg once daily (QD)); the third group received MeCbl alone (C group). All patients received optimized treatment to lower blood glucose, blood pressure, and blood lipids to target levels. The efficacy of lipo-PGE1 in the three groups of patients was observed after 3weeks of treatment. RESULTS: The overall response rate was 90% in the B group, significantly higher than that in the A and C groups (80% and 55%, respectively; P<0.05). During the observation period, there was no incidence of serious adverse reactions (e.g., acute heart failure, sudden drop in blood pressure, or malignant arrhythmias) in any of the three groups. CONCLUSIONS: High-dose lipo-PGE1 has better efficacy than low-dose lipo-PGE1 or MeCbl alone in the treatment of painful DPN.

Mechanism of Tang Luo Ning effect on attenuating of oxidative stress in sciatic nerve of STZ-induced diabetic rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Tang Luo Ning recipe (TLN), a traditional Chinese herbal medicine based on Huangqi Guizhi Wuwu decoction, has been used clinically to treat diabetic peripheral neuropathy in China. However, the effect of TLN on diabetic peripheral neuropathy is unclear. The objective of this study was to determine the main components in TLN and to investigate the effects of TLN on oxidative stress in diabetic peripheral neuropathy rats. MATERIALS AND METHODS: The effect of TLN on oxidative stress was investigated in streptozocin (STZ)-induced diabetic rats. Fasting blood glucose, body weight, thermal perception threshold test and motor and sensory nerve conduction velocity of sciatic nerve were measured. Sciatic nerve morphology was observed by Haematoxylin and eosin staining and under transmission electron microscope. T-AOC was measured by colorimetric assay. ROS were measured using enzyme-linked immunosorbent assay. Nrf2 and γGCS protein levels were measured by Western blot analysis. The expression of Bcl2, Bax and Cyto C were examined by immunohistochemistry. RESULTS: TLN markedly improved the neurological function including thermal perception threshold and nerve conduction velocity of DPN rats. Haematoxylin and eosin (HE) and transmission electron microscopy (TEM) staining results showed that TLN attenuated axon atrophy and demyelination in DPN rats. Moreover, TAOC were increased, whereas ROS content was decreased after treatment with TLN in rats with DPN. Furthermore, TLN increased protein levels of Nrf2, γGCS and Bcl2, and decreased Bax and Cyto C expression. CONCLUSIONS: TLN improved neurological function to prevent diabetic peripheral neuropathy by attenuating oxidative stress through Nrf2 and Bcl2 activation.

Antioxidation and anti-inflammatory activity of Tang Bi Kang in rats with diabetic peripheral neuropathy.

BACKGROUND: Tang Bi Kang (TBK) is a traditional Chinese medicine granule. It has been shown to have effects on nerve conduction velocity deficits, blood-related factors and oxidative stress. This study was undertaken to evaluate proposed antioxidative and anti-inflammatory activity of Tang Bi Kang in rats with diabetic peripheral neuropathy (DPN). METHODS: DPN was induced in male Wistar rats by intraperitoneal administration of streptozocin (STZ) (60 mg/kg.b.w) for 8 weeks. Fasting blood glucose (FBG) levels were measured in the blood obtained by clipping the tails of the rats. Tail-flick tests were conducted with a tail-flick analgesic meter. Motor and sensory nerve conduction velocities (MNCV and SNCV) of sciatic nerve were measured directly at two sites using a Functional Experiment System. Oxidative stress makers such as malondialdehyde (MDA), superoxide-dismutase (SOD) and glutathione peroxidase (GSH-Px), inflammatory cytokines such as interleukin (IL)-6, and tumour necrosis factor (TNF)-α were estimated. The statistical analysis of results was carried out using Student t-test and one-way analysis of variance (ANOVA), followed by least-significant difference post hoc with SPSS. RESULTS: The administration of TBK for 4 weeks in DPN rats resulted in a significant decrease in FBG levels compared to untreated DPN rats. There was a significant increase in MNCV and SNCV in the DPN rats compared to untreated DPN rats. Serum level of MDA was significantly reduced while the activities of SOD and GSH-pX were significantly increased in the TBK treated DPN rats. TBK prevented DPN-induced increase in the serum levels of IL-6 and TNF-α. CONCLUSION: The results of this study demonstrate that the therapeutic effect of TBK on DPN rats may be associated with the antioxidative and anti-inflammatory responses.

Lowering plasma 1-deoxysphingolipids improves neuropathy in diabetic rats.

1-Deoxysphingolipids (1-deoxySLs) are atypical neurotoxic sphingolipids that are formed by the serine-palmitoyltransferase (SPT). Pathologically elevated 1-deoxySL concentrations cause hereditary sensory and autonomic neuropathy type 1 (HSAN1), an axonal neuropathy associated with several missense mutations in SPT. Oral L-serine supplementation suppressed the formation of 1-deoxySLs in patients with HSAN1 and preserved nerve function in an HSAN1 mouse model. Because 1-deoxySLs also are elevated in patients with type 2 diabetes mellitus, L-serine supplementation could also be a therapeutic option for diabetic neuropathy (DN). This was tested in diabetic STZ rats in a preventive and therapeutic treatment scheme. Diabetic rats showed significantly increased plasma 1-deoxySL concentrations, and L-serine supplementation lowered 1-deoxySL concentrations in both treatment schemes (P < 0.0001). L-serine had no significant effect on hyperglycemia, body weight, or food intake. Mechanical sensitivity was significantly improved in the preventive (P < 0.01) and therapeutic schemes (P < 0.001). Nerve conduction velocity (NCV) significantly improved in only the preventive group (P < 0.05). Overall NCV showed a highly significant (P = 5.2E-12) inverse correlation with plasma 1-deoxySL concentrations. In summary, our data support the hypothesis that 1-deoxySLs are involved in the pathology of DN and that an oral L-serine supplementation could be a novel therapeutic option for treating DN.

An evaluation of the protective role of Ficus racemosa Linn. in streptozotocin-induced diabetic neuropathy with neurodegeneration.

OBJECTIVE: Ficus racemosa (FR) is one of the herbs mentioned in the scriptures of the Ayurveda as Udumbara with high medicinal value. The objective of this study was to estimate the protective effect of FR against streptozotocin (STZ) induced diabetic neuropathy with neurodegeneration (DNN). MATERIALS AND METHODS: Diabetes was induced in Wistar rats with STZ and were divided into six groups namely diabetic vehicle control, FR (four) and glibenclamide (one) treated rats; while one group was of normal control rats. After the 4(th) week of diabetes, induction treatment was started for further 28 days (5(th) to 8(th) week) with FR aqueous extract (250 mg/kg and 500 mg/kg) and ethanolic extract (200 mg/kg and 400 mg/kg). Investigation of DNN was carried out through biochemical and behavioral parameter assessment in rats. RESULTS: Study showed a significant fall in glycosylated hemoglobin (HbA1c) and blood glucose level by the treatment of FR in diabetic rats. Antioxidant potential of FR showed a great rise in superoxide dismutase, catalase content and reduction observed in serum nitrite level; while significant fall in lipid peroxidation level and of C-reactive protein was observed in FR treated diabetic rats. Further FR treated diabetic rats also showed marked improvement in tail flick latency, pain threshold, the rise in locomotion and fall latency period. CONCLUSION: Treatment with FR shows protection in the multiple pathways of DNN by improving blood glucose, HbA1c, biochemical, and behavioral parameters, which suggest the protective role of FR in the reversal of DNN.