Increase in plasma glucose lowering action of rosiglitazone by electroacupuncture at bilateral Zusanli acupoints (ST.36) in rats

Effects of electroacupuncture at ST36 and BL20 on the diabetic rat testis

OBJECTIVE

We aimed to evaluate the effects of electroacupuncture (EA) at ST36 and BL20 on the testicular tissues in a rat model of diabetes and to explore the mechanisms of action.

METHODS

A total of 34 male Sprague-Dawley rats were allocated to a control group (n = 10), diabetes (D) group (n = 12) or diabetes + acupuncture (DA) group (n = 12). To model diabetes, rats in groups D and DA received an intraperitoneal injection of a single dose of 35 mg/kg streptozotocin (STZ) dissolved in citrate buffer (pH = 4.5; 0.1 M) after 2 weeks of high-fat diet administration. Under xylazine/ketamine anesthesia, stainless steel needles (30 mm × 0.25 mm) were inserted bilaterally at ST36 and BL20. The needles were connected to an EA device via cables, and EA was applied for 30 min (15 Hz frequency and 0.2-1 mA intensity) twice a week for 5 weeks.

RESULTS

The effects of EA at ST36 and BL20 on blood glucose levels and body weight, biochemical parameters, histopathological, morphometric and immunohistochemical findings, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) analysis were evaluated. A significant decrease was detected in DA versus D groups in blood glucose levels, basement membrane thickness and apoptotic cell/tubule indices. In addition, there was a significant increase in the Johnsen scores, seminiferous tubule diameters, serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone, proliferation indices, and sex hormone-binding globulin (SHBG) and insulin-like peptide 3 (INSL3) immunoreactivities.

CONCLUSION

EA had multiple positive effects on blood glucose homeostasis and testicular structure/function in this rat model of diabetes. EA may be effective at preventing or eliminating histopathological damage in the diabetic testis.

Electroacupuncture improves cognitive deficits and insulin resistance in an OLETF rat model of Al/D-gal induced aging model via the PI3K/Akt signaling pathway

To investigate the effect of electroacupuncture (EA) on cognitive function and insulin resistance (IR) in an Al/D-gal-induced aging model for Alzheimer's disease (AD) using Ostuka Long-Evans Tokushima Fatty (OLETF) rats. The Al/D-gal-OLETF rats for AD were randomly divided into the EA and non-EA groups. Cognitive function was assessed using the Morris water maze (MWM). The morphology of the hippocampal neurons was observed using hematoxylin & eosin (H&E) staining. Aβ and total Tau in the hippocampus and cerebrospinal fluid (CSF) were detected using western blotting (WB) and enzyme-linked immunosorbent assay (ELISA). Fasting blood glucose (FPG) was determined using the glucose oxidase method. Plasma fasting insulin (FINS), serum C-peptide (C-P), and CSF insulin were detected using ELISA. The expression of the genes and proteins in the PI3K signaling pathway was detected using quantitative real-time PCR and WB. After EA intervention, the hippocampal Aβ and total Tau protein levels, body weight, FPG, FINS, and C-P were significantly decreased. The MWM showed that the percentage of time in the target quadrant of the EA group was elevated in the probe test. The protein levels of p-IRS1, p-IRS2, IDE, and p-GSK3β were significantly increased, while p-PI3K-p85α and p-Akt were decreased. In conclusion, EA improves cognitive function and insulin resistance in rat models of AD. The PI3K/Akt signaling pathway is involved in those changes.

Effect of electrical stimulation combined with diet therapy on insulin resistance via mTOR signaling

Insulin resistance (IR) is the impaired insulin response that causes decreased glucose tolerance. Electrical stimulation (ES) can improve insulin sensitivity in the skeletal muscle. However, the underlying molecular mechanisms remain to be elucidated. In the present study, the effect of ES and diet therapy on IR and the role of the mammalian target of rapamycin (mTOR) pathway in the improvement of IR by ES were investigated. A total of 70 Sprague-Dawley male rats were divided into five groups: Normal (n=10), IR control (n=15), diet (n=15), ES (n=15) and ES + diet (n=15) groups. An IR rat model was established by high-fat and high-carbohydrate diet for 5 weeks and confirmed by measurement of fasting plasma glucose (FPG), insulin, insulin sensitivity index (ISI) and IR index. ES on the Zusanli (ST36), Sanyinjiao (SP 6) and Weiwanxiashu (EX-B3) acupoints and the low-fat and low-carbohydrate diet demonstrated protective effects. The body weight, concentrations of FPG, insulin, triglycerides (TG), free fatty acids (FFA) and total cholesterol (TC) of the rats were detected. Pathologic changes in the liver and pancreatic tissues were assessed. Western blotting and immunohistochemistry were performed to determine the role of PI3K/Akt/mTOR signaling. Results demonstrated that ES and diet therapy significantly increased ISI and reduced FPG, IR index, FFA, TG, TC and weight. Inflammatory cell infiltration in the liver and pancreatic tissues was ameliorated and lipid droplets and cavitation in hepatocyte were decreased after ES and diet therapy. The administration of ES and diet therapy also enhanced glucose transport by the upregulation of glucose transporter 4 and accelerated glycogen synthesis through the suppression of glycogen synthase kinase 3α/β via PI3K/Akt/mTOR signaling. Hence, the present results demonstrated that ES combined with diet therapy improved IR through PI3K/Akt/mTOR signaling. The proposed therapy was superior to the method of diet alone.

Acupuncture for type 2 diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Acupuncture has been used to treat type 2 diabetes (T2DM) for 2000 years and there are emerging clinical evidence and animal studies for its efficacy. However, we are unable to conclude the effectiveness and safety on this issue yet.

OBJECTIVES

To assess the effects and safety of acupuncture for T2DM.

METHODS

We systematically searched 5 databases and 2 clinical registry platforms from inception to 2018-6-4. RCTs for acupuncture or its variants compared with sham acupuncture or no acupuncture controls for T2DM were included. The primary outcomes were glycemic control and adverse events.

RESULTS

A total of 21 studies, which comprised a total of 1943 participants, were included in the final meta-analysis. Compared with sham acupuncture or no acupuncture plus baseline treatments, acupuncture plus baseline treatments yield reduction in FBG(MD 1.21 mmol/l, 95%CI 1.56 to 0.87), 2 h BG(MD 2.13 mmol/l, 95%CI 2.79 to 1.46), HA1c (MD 1.12%, 95%CI 1.62 to 0.62). Our results also show acupuncture can improve blood lipids and blood pressure control, and reduce weight.

CONCLUSIONS

As one type of multifactorial intervention, acupuncture could be recommended as a supplementary treatment in the management of T2DM, especially in those with obesity or metabolic disorders. However, due to the small sample size, poor methodological quality of trials reviewed, the amount of evidence is not fully convincing. There is a need for well-planned, long-term studies.

REGISTRATION

International Prospective Register of Systematic Reviews (Number CRD42018094573).

Effect on glycemia in rats with type 2 diabetes induced by streptozotocin: low-frequency electro-pulse needling stimulated Weiwanxiashu (EX-B 3) and Zusanli (ST 36)

OBJECTIVE

To investigate the effect of low frequency electro-pulse acupuncture (EA) on blood glucose in rats with streptozotocin-induced type 2 diabetes, and the possible mechanism underlying the action.

METHODS

Rat models were established with high fat feeding and intraperitoneal injection of streptozotocin (STZ) (30 mg/kg). Rats with a random blood glucose > 16.7 mmol/L and blood glucose at 2 h-point of oral glucose tolerance test (OGTT) > 11.1 mmol/L were included as diabetic rats, and randomly divided into model group, EA Weiwanxiashu (EX-B 3) group, EA Zusanli (ST 36) group, glimepiride group, and EA non-acupoint group (n = 12). EA (2 Hz continuous wave, 2 mA, 20 min/day, 6 days/week, 4 weeks) and intra-gastric administration of glimepiride were applied as interventions. With fasting blood glucose and OGTT tested at the end of the intervention, the study observed the patterns of hypoglycemic effects. For mechanism study, it observes hematoxylin and eosin staining and Masson staining of pancreas paraffin sections, protein expression of glucagon- like peptide 1 receptor (GLP-1R) in the pancreas and skeletal muscle, glucose transporter 4 (GLUT4) protein expression in skeletal muscle membrane, to detect whether EA controls blood glucose via regulation of GLP-1R.

RESULTS

EA Weiwanxiashu (EX-B 3) significantly increased model rats' pancreas GLP-1R, and GLUT4 of skeletal muscle membrane; the therapy significantly decreased model rats' skeletal muscle GLP-1R, restored pancreas morphology, and reduced fasting blood glucose and insulin resistance indices.

CONCLUSION

EA Weiwanxiashu (EX-B 3) alone has significant effect on glycemia. EA Weiwanxiashu (EX-B 3) plus glimepiride further strengthen the effect. The regulation of the GLP-1R in pancreas and skeletal muscle might be mechanism underpinning the effect.

Effect of Peripheral Electrical Stimulation (PES) on Nocturnal Blood Glucose in Type 2 Diabetes: A Randomized Crossover Pilot Study

BACKGROUND

Regulation of hepatic glucose production has been a target for antidiabetic drug development, due to its major contribution to glucose homeostasis. Previous pre-clinical study demonstrated that peripheral electrical stimulation (PES) may stimulate glucose utilization and improve hepatic insulin sensitivity. The aim of the present study was to evaluate safety, tolerability, and the glucose-lowering effect of this approach in patients with type 2 diabetes (T2DM).

METHODS

Twelve patients with T2DM were recruited for an open label, interventional, randomized trial. Eleven patients underwent, in a crossover design, an active, and a no-intervention control periods, separated with a two-week washout phase. During the active period, the patients received a daily lower extremity PES treatment (1.33Hz/16Hz burst mode), for 14 days. Study endpoints included changes in glucose levels, number of hypoglycemic episodes, and other potential side effects. Endpoints were analyzed based on continuous glucose meter readings, and laboratory evaluation.

RESULTS

We found that during the active period, the most significant effect was on nocturnal glucose control (P < 0.0004), as well as on pre-meal mean glucose levels (P < 0.02). The mean daily glucose levels were also decreased although it did not reach clinical significance (P = 0.07). A reduction in serum cortisol (P < 0.01) but not in insulin was also detected after 2 weeks of treatment. No adverse events were recorded.

CONCLUSIONS

These results indicate that repeated PES treatment, even for a very short duration, can improve blood glucose control, possibly by suppressing hepatic glucose production. This effect may be mediated via hypothalamic-pituitary-adrenal axis modulation.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02727790.

Regulation of glucose dynamics by noninvasive peripheral electrical stimulation in normal and insulin-resistant rats

BACKGROUND

The epidemic nature of type 2 diabetes mellitus (T2DM), along with the downsides of current treatments, has raised the need for therapeutic alternatives.

METHODS

We studied normo-glycemic and high-fat diet (HFD), induced insulin-resistant Wistar Han rats for 2 to 3weeks. Rats received peripheral electrical stimulation (PES) treatment (2Hz/16Hz bursts, 10mA) in their hind limbs for 3min, 3 times per week. Glucose tolerance was evaluated by using a glucose tolerance test at the beginning and again at the end of the study. The effect of an acute PES treatment on metabolic rates of glucose appearance and turnover was measured by using the hyperinsulinemic-euglycemic clamp (HEGC) test.

RESULTS

Repeated PES treatment significantly inhibited the progression of glucose intolerance in normal and insulin-resistant rats and prevented HFD-induced gains in body weight and fat mass. Acute treatment induced a prolonged effect on glucose turnover, as evaluated by the HEGC test. Increased hepatic glucose output was observed during the basal state (P<0.005). Under hyperinsulinemic conditions, PES improved tissue sensitivity to insulin (41.1%, P<0.01), improved suppression of hepatic glucose production (58.9±4.4% vs. 87.1±4.4%, P<0.02) and significantly elevated the rate of glycogenesis (P<0.01), compared with controls.

CONCLUSIONS

The present study indicates that a noninvasive PES treatment of very short duration is sufficiently potent to stimulate glucose utilization and improve hepatic insulin sensitivity in rats. Repeated PES treatment may have a beneficial effect on HFD-induced adiposity and control of body weight.

Electroacupuncture prevents white adipose tissue inflammation through modulation of hypoxia-inducible factors-1α-dependent pathway in obese mice

BACKGROUND

Electroacupuncture (EA) shows anti-inflammation and several pleiotropic effects that interact with metabolic pathways. In the present study we tested the hypothesis that EA prevents inflammatory response and weight gain in obese mice through modulation of hypoxia-inducible factors-1α (HIF1-α)-dependent pathways in white adipose tissues.

METHODS

Mice were divided in 4 groups: Non-obese, ob/ob, ob/ob submitted to 3 treatments, ob/ob submitted to 7 treatments. Low-frequency EA (2 Hz) was applied at the Zusanli (ST36) acupoint 10 min three times weekly for one or two consecutive weeks in male ob/ob mice. At 22 weeks of age, plasma lipid, glucose, other metabolites and relevant markers were measured by standard assays. Adipose tissue was assessed with immunohistochemical staining. Adipose tissue extracts were also analyzed with quantitative real-time polymerase chain reaction (Q-PCR) and Western blotting.

RESULTS

EA treatment is associated with decreased adipose tissue inflammation, and markedly decreased fat mass and adipocyte size in ob/ob mice. In obese mice, The protein levels of HIF-α were increased, EA shown a marked trend in inhibiting the hypoxic response in adipose tissue. The expression level of hypoxia-related genes (vascular endothelial growth factor A, VEGFA; glucose transporter type 1, Slc2al; glutathione peroxidase 1, GPX1) and inflammation-related genes (TNF-α, IL-6, MCP-1) expression were also reduced in adipose tissue after EA treatment. EA treatment decreased the macrophage recruitment and infiltration (F4/80), and in addition we found that decrease in NF-κB and increase in IkBα were both correlated to reduction in inflammatory processes in adipose tissue. This phenomenon was paralleled by the decrease in the levels of inflammatory cytokines, such as TNF-α, IL-6 and IL-1β in obese mice.

CONCLUSIONS

We conclude that EA prevents weight gain through modulation of HIF-1α-dependent pathways and inflammatory response in obese adipose tissues.

Acupoint-specific, frequency-dependent, and improved insulin sensitivity hypoglycemic effect of electroacupuncture applied to drug-combined therapy studied by a randomized control clinical trial

The application of electroacupuncture (EA) to specific acupoints can induce a hypoglycemic effect in streptozotocin-induced rats, normal rats, and rats with steroid-induced insulin resistance. EA combined with the oral insulin sensitizer rosiglitazone improved insulin sensitivity in rats and humans with type II diabetes mellitus (DM). There are different hypoglycemic mechanisms between Zhongwan and Zusanli acupoints by EA stimulation. On low-frequency (2 Hz) stimulation at bilateral Zusanli acupoints, serotonin was involved in the hypoglycemic effect in normal rats. Moreover, after 15 Hz EA stimulation at the bilateral Zusanli acupoints, although enhanced insulin activity mainly acts on the insulin-sensitive target organs, the muscles must be considered. In addition, 15 Hz EA stimulation at the bilateral Zusanli acupoints has the combined effect of enhancing cholinergic nerve activity and increasing nitric oxide synthase (NOS) activity to enhance insulin activity. Despite the well-documented effect of pain control by EA in many systemic diseases, there are few high-quality long-term clinical trials on the hypoglycemic effect of EA in DM. Combination treatment with EA and other medications seems to be an alternative treatment to achieve better therapeutic goals that merit future investigation.

Electroacupuncture and rosiglitazone combined therapy as a means of treating insulin resistance and type 2 diabetes mellitus: a randomized controlled trial

Aims. To evaluate the efficacy of rosiglitazone (TZD) and electroacupuncture (EA) combined therapy as a treatment for type 2 diabetes mellitus (T2DM) patients by randomized single-blind placebo controlled clinical trial. Methods. A total of 31 newly diagnostic T2DM patients, who fulfilled the study's eligibility criteria, were recruited. The individuals were randomly assigned into two groups, the control group (TZD, N = 15) and the experimental group (TZD + EA, N = 16). Changes in their plasma free fatty acid (FFA), glucose, and insulin levels, together with their homeostasis model assessment (HOMA) indices, were statistically compared before and after treatment. Hypoglycemic activity (%) was also compared between these two groups. Results. There was no significant difference in hypoglycemic activity between the TZD and TZD + EA group. The effectiveness of the combined therapy seems to derive from an improvement in insulin resistance and a significant lowering of the secreted insulin rather than the effect of TZD alone on T2DM. The combined treatment had no significant adverse effects. A lower plasma FFA concentration is likely to be the mechanism that causes this effect. Conclusion. This combined therapy seems to suppress endogenous insulin secretion by improving insulin resistance via a mechanism involving a reduction in plasma FFA. This trial is registered with ClinicalTrials.gov NCT01577095.

Acupuncture stimulation and neuroendocrine regulation

Acupuncture has been used to treat different conditions for at least 3000 years in China and has gained increasing acceptance worldwide. The acupuncture needle inserted into the muscle layer at the acupoint produces the so-called obtaining qi sensation that causes the excitation of A-δ and C-fibers of the muscle tissue, resulting in afferent signals. The afferent signals pass through the dorsal horn cells of the spinal cord ascending to the brain, such as the hypothalamus, enhancing the release of neuropeptides and hormones, and these afferent signals in the spinal segment may innervate the visceral organ, inducing effect on visceral function. Here, we reviewed the effect of acupuncture stimulation on neuropeptides and hormones, including β-endorphin, serotonin, oxytocin, adrenocorticotropic hormone, gonadotropin-releasing hormone, corticotrophin-releasing hormone, cholecystokinin, and acetylcholine, as well as insulin sensitivity, immunomodulation (anti-inflammation), and autonomic nerve activity.

Electroacupuncture for control of blood glucose in diabetes: literature review

Electrical stimulation at acupuncture points (acupoints) has been investigated for its utility in lowering blood glucose in hyperglycemic humans and animal models. Only two studies were found using electroacupuncture in human subjects, and in both of these, the participants were normal (nondiabetic) and electrical stimulation was carried out at several acupoints. It had a hypoglycemic effect in obese women with calorific restriction diet using electrical stimulation of 2 Hz for 30 minutes/day for 20 days, but no change occurred in blood glucose of fasted patients in the other study using 1 Hz for 15 minutes. Fourteen animal studies were found, of which, 11 were performed in diabetic and normal rats. A hypoglycemic effect was observed in fasted type 1 diabetic rats using the Zusanli (ST36) leg acupoint with electrical stimulation of 15 Hz for 30 minutes and 60 minutes. In fasted type 2 diabetic rats, blood glucose was lowered using the Zusanli acupoint with electrical stimulation parameters of 15 Hz and 10 mA for 30 minutes. Also, using the Zhongwan (CV12) abdomen acupoint with electrical stimulation parameters of 15 Hz and 10 mA for 90 minutes had a hypoglycemic effect in fasted type 2 diabetic rats. In fasted normal rats, electrical stimulation of 2 Hz or 15 Hz for 30 minutes at the Zusanli or Zhongwan acupoint caused a decrease in blood glucose. Future studies are required in fasted diabetic rats to determine the effect of electroacupuncture on blood levels of insulin, lipids, fatty acids and β-endorphin, and blood flow and nerve conduction velocity. Studies with fasted normal and diabetic human subjects treated by electroacupuncture are warranted using data from animal experiments to inform such studies.

Progress in treatment of gastrointestinal functional disorders by electroacupuncture at Zusanli

Electroacupuncture at human acupuncture points has an important impact on gastrointestinal motility. Zusanli, the He-sea point of the Stomach Meridian of Foot-Yangming, is one of the most common points for electroacupuncture. Electroacupuncture at Zusanli at a specific frequency can improve gastrointestinal functional diseases, such as gastroesophageal reflux, functional dyspepsia, and irritable bowel syndrome. Although there is still controversy over the efficacy of electroacupuncture at Zusanli for gastrointestinal functional diseases, many studies support the notion that electroacupuncture at Zusanli plays an important role in modulating gastrointestinal functional diseases. In this paper we review the recent progress in the treatment of gastrointestinal functional diseases by electroacupuncture at Zusanli.

Electroacupuncture at the Zusanli (ST-36) Acupoint Induces a Hypoglycemic Effect by Stimulating the Cholinergic Nerve in a Rat Model of Streptozotocine-Induced Insulin-Dependent Diabetes Mellitus

Animal studies have shown that electroacupuncture (EA) at Zusanli (ST-36) and Zhongwan (CV-12) acupoints reduces plasma glucose concentrations in rats with type II diabetes. However, whether EA reduces plasma glucose levels in type I diabetes is still unknown. In this study, we explore the various non-insulin-dependent pathways involved in EA-induced lowering of plasma glucose. Streptozotocin (STZ) (60 mg kg⁻¹, i.v.) was administered via the femoral vein to induce insulin-dependent diabetes in non-adrenalectomized and in adrenalectomomized rats. EA (15 Hz) was applied for 30 min to bilateral ST-36 acupoints after administration of Atropine (0.1 mg kg⁻¹ i.p.), Eserine (0.01 mg kg⁻¹ i.p.), or Hemicholinium-3 (5 μg kg⁻¹ i.p.) in non-adrenalectomized rats. Rats administered acetylcholine (0.01 mg kg⁻¹ i.v.) did not undergo EA. Adrenalectomized rats underwent EA at bilateral ST-36 acupoints without further treatment. Blood samples were drawn from all rats before and after EA to measure changes in plasma glucose levels. Expression of insulin signaling proteins (IRS1, AKT2) in atropine-exposed rats before and after EA was measured by western blot. Atropine and hemicholinium-3 completely blocked the plasma glucose lowering effects of EA, whereas eserine led to a significant hypoglycemic response. In addition, plasma glucose levels after administration of acetylcholine were significantly lower than the fasting glucose levels. In STZ-adrenalectomized rats, EA did not induce a hypoglycemic response. EA stimulated the expression of IRS1 and AKT2 and atropine treatment blocked the EA-induced expression of those insulin signaling proteins. Taken together, EA at the ST-36 acupoint reduces plasma glucose concentrations by stimulating the cholinergic nerves.