Yu-Qing Sun,Sheng Peng,Yu-Ling Wang,Si-Qing Zhang,Wen-Rui Wang

1Graduate College, Tianjin University of Traditional Chinese Medicine, Tianjin, China; 2Clinical College, Tianjin Nankai Hospital,Tianjin,China.

Abstract Diabetes,as a chronic incurable disease,not only causes acute complications such as hyperglycemic hyperosmolar status,ketoacidosis and hypoglycemia,but also affects arteries and nervous system,causing the eyes,kidneys,feet,blood vessels, nerves and other organs or tissues damage, and leading to the occurrence and development of chronic diseases.The World Health Organization believes that diabetes may be the most important non-communicable global disease caused by unhealthy modern lifestyles and regards it as a major global health problem.At present, there is still a lack of specific drugs for the treatment of diabetes, and related treatment drugs are often accompanied by adverse reactions.Auricular therapy as a non-drug, non-invasive treatment method show unique advantages in the treatment of diabetes.This article reviews the mechanism of auricular therapy and its application status in diabetes,in order to broaden the mind for the auricular therapy to treat diabetes.

Keywords:Diabetes;auricular therapy;Review

Introduction

Diabetes Mellitus (DM) is one of the most common chronic endocrine diseases in the 21st century[1].It is mainly due to insulin resistance or insufficient secretion.The blood sugar level in the body has been at a high value for a long time, leading to serious disorders of carbohydrate, fat and protein metabolism.Its pathogenesis has not yet been fully elucidated.In recent years, as the economic income of Chinese residents has increased, people’s lifestyles and living habits have been different from before.Their diets tend to be fat, sweet, rich and greasy, and their work styles have also been sedentary,which has led to an increase in the incidence of diabetes.The incidence of diabetes has increased significantly in the past ten years,from 4.5% in 2008 to 11.2% in 2018[2,3].The medical and economic burden of diabetic patients is not only related to the treatment of hyperglycemia, but also related to the prevention and control of chronic complications of diabetes [4].Auricular therapy, as a traditional traditional Chinese medicine treatment method, is gradually accepted by diabetic patients due to its simple operation, precise curative effect, high tolerance, economic and safe, and it has shown good results in disease treatment, prevention and control of complications [5].Current studies have shown that auricular therapy has clinical effects such as steady lowering of blood sugar, improving sleep quality,relieving symptoms of constipation, and correcting negative emotions.

The development and current situation of auricular therapy

Auricular therapy is an important part of Chinese acupuncture.As early as more than 5,000 years ago,there was a record of "ear pulse" in ancient Chinese medicine, "Huangdi Neijing" first proposed the principle of auricular therapy and recorded application cases,In the medical books written by Sun Simiao, a medical pharmacist in the Tang Dynasty, and Yang Jizhou,a acupuncturist in the Ming Dynasty,all record the location, indications and operation methods of some auricular point; In the "Lizheng Massage Essentials" written by Zhang Zhenjun, physician in Qing Dynasty, the auricle is divided into five parts:heart, liver, spleen, lung, and kidney, and draw the ear points chart.Auricular therapy has been passed down and developed over a long period of time in various dynasties and has become a common part of traditional Chinese medical practices.In 1957, French surgeon P.Nogier marked each part of the human body at the corresponding acupoints of the auricle one by one,forming a map of "inverted fetus".In 2010, the World Federation of Acupuncture-Moxibustion Societies promulgated the "Name and Position of Auricular Points", which opened the way for modernized research on auricular therapy.At present, the functions and positioning of more than 200 auricular point have been clarified, involving internal, external, women,children, bone trauma, emergency and many other departments [6,7], and they are widely used in countries around the world [8].Auricular therapy has the advantages of simplicity,convenience,effectiveness, and low cost.There is no harm to patients, less irritation,and high patient acceptance, so it is worthwhile to promote this Chinese medicine technique.

Mechanism of auricular points

In 2008, China formulated the national standard"Auricular Acupoint Name and Position" [9], which divided the auricle into nine parts and 93 auricular point.Based on traditional viscera meridians and modern related theories, auricular therapy have been shown to be closely related to the limbs.By stimulating specific acupoints on the auricle, they can cause comprehensive changes in the central nervous system, endocrine system and peripheral nervous system[10].

Auricular point holographic biological theory

The holographic biological theory was proposed by Professor Zhang Yingqing.This theory believes that all the relatively independent parts of each organism that have life functions include all the information of the whole.The contour of the ear is like the shape of the fetus in the mother,which can be regarded as a miniature figure, which is a typical holographic phenomenon of life, so the auricular point belong to the holographic acupoint system [11], The physical changes of the auricle and its surrounding surface are the holographic projections of the pathophysiological conditions of the corresponding parts of the human body.The auricle diagnosis method is invented based on this phenomenon.Chinese scholar Chen Shaozong pointed out that the mechanism of the holographic phenomenon of auricle points may be that each acupuncture point of the auricle has a bidirectional specific synaptic connection with its corresponding integral part of the projection in the central center.This connection is mainly controlled by the system of holographic connection between the nerves innervating the auricle and the nerves innervating the body in the network structure of the brainstem [12].Therefore,according to the holographic biological theory,acupuncture or bean burial treatment at the corresponding acupoints of the disease can achieve the effect of adjusting the corresponding overall and partial functions.

Theoretical basis of Traditional Chinese Medicine

The theory of traditional Chinese medicine believes that the human is a whole, and the ears are closely related to the internal organs,limbs and skeletal bodies of the human body.By stimulating specific parts of the auricle, it can positively regulate the function of the body."Lingshu" pointed out that "ear is the place where the Meridian are gathered"."Lizheng Massage Essentials"records:"The earlobe belongs to the kidney,the helix belongs to the spleen, the opposite helix belongs to the heart, the ear skin belongs to the lung,and the bulge behind the ear belongs to the liver".The"Huangdi Neijing" records the meridian directions in detail：the six yang meridians directly pass through the ears, while the six yin meridians are in line with the yang meridians on the head and face, and can have an indirect connection with the ear.In summary,acupuncture points on the auricle are related to the internal organs and the twelve meridians.By stimulating the corresponding ear points, it can regulate the meridians of the whole body and stimulate the related viscera, so that the twelve meridians are harmonized and the functions of the viscera are coordinated.Therefore, the "qi" and "blood" are unobstructed and diseases can be eliminated.

Neurohumoral regulation

The auricle is distributed with abundant nerves,among which the vagus nerve endings and visceral nerve endings all converge in the auricle, and it is also the only part of the human body where the afferent vagus nerve is distributed [13].Studies [14] have found that stimulating visceral nerve endings can excite the central nervous system related to the regulation of visceral function,and conduct it to the pancreatic islets through the nucleus tractus solitarius to promote the release and secretion of insulin from the islet acinar and ducts,and then play a role in regulating blood sugar.Mei ZG et al.[15] stimulated the distribution area of the vagus nerve in the ears of rats and found that it can reduce the blood sugar level of rats, and the blood sugar dropped to the lowest 10 minutes after the stimulation stopped;According to electrophysiological experiments,stimulating the vagus nerve reflex area of the auricle can activate glucose-sensitive and insulin-sensitive neurons, activate the insulin system reflex, and achieve the effect of lowering blood sugar.In addition, another study found that the ear-vagus-visceral reflex can cause benign liver glucose metabolism, activate the cholinergic pathway to promote the pancreas to secrete insulin,and enhance the peripheral sensitivity of insulin [16].Since the auricle has less muscles, it can stimulate the nervous system more strongly through auricular stimulation,which can promote the positive regulation of hormones in the body.

Auricular therapy application progress in diabetes

Hypoglycemic effect

The core of diabetes treatment is the control of blood sugar [17].Maintaining a normal level of blood sugar helps control the condition of diabetes, prevents the occurrence and development of acute and chronic complications of diabetes, and reduces the risk of infection in patients [18].Chen H et al.[19] observed the effect of Acupuncture therapy on blood sugar regulation in diabetic patients.The acupuncture points were Shenmen, pancreas, and stomach.The stimulation time was within half an hour after breakfast and the acupuncture duration was 4 hours.The blood glucose levels of the patient were measured on an empty stomach, 2 hours after breakfast, and 4 hours after breakfast on the day before, on the day of acupuncture, and one day after the acupuncture.The results showed that compared with the day before the acupuncture, the blood glucose level 2 hours after breakfast on the day of acupuncture and the day after the acupuncture was significantly lower, but there was no significant improvement effect on the blood glucose level 4 hours after breakfast and fasting.Liu XR et al.[20] conducted a randomized cross-over controlled trial on diabetic patients.Acupuncture at the peripheral vagus nerve distribution area of the auricle of diabetic patients.The acupuncture time and indwelling time were the consistent with the research of Chen H et al.Through the comparison of patients before and after and between groups, the same research results were obtained, which proved that auricular therapy treatment can effectively alleviate the blood glucose level of 2 hours after a meal, and its hypoglycemic effect can last until one day after treatment.Su W et al.[21] performed acupuncture ear points treatment on patients with prediabetes.The acupuncture site selected the positive point of ear tenderness, and the needle was retained for half an hour each time.The treatment frequency was every other day in the first month and once a week in the next 2 months.After three months of treatment,the total effective rate of the patient's clinical treatment was 63.3%, and the control level of glucose metabolism index was significantly lower than the control group and the level before self-intervention.The above studies have shown that auricular therapy not only has the effect of timely lowering blood sugar, but also has significant clinical significance for long-term blood sugar control, and is safe and without side effects.It can be used as a long-term clinical treatment for patients with type 2 diabetes.

Relieve negative emotions in diabetic patients

Previous studies have shown that patients with diabetes have an increased risk of depression compared with non-diabetic patients[22].This may be due to the long-term continuous treatment of the disease and the risk of potential complications, which will have a greater impact on the patient’s physiology and psychology.In addition,the long-term high blood sugar value causes partial blood vessel damage, which may induce brain pathology and lead to susceptibility to mental illness [23].Since emotions affect blood sugar control [24], it is also important to adopt active and effective intervention methods to relieve the negative emotions of diabetes.Xiang YY et al.[25] randomly divided 100 diabetes patients with anxiety and depression into two groups.The control group received routine symptomatic treatment, on the basis of the control group, the intervention group added Beans in Ear Points combined with acupoint massage.Choose Shenmen, Sympathy, Sanjiao, Liver, Spleen, Heart,and Subcortex for ear acupuncture pressure points.Press three times a day, pressing each point for one minute each time; Acupoint massage takes Neiguan acupoint,and the treatment duration and frequency are the same as ear acupoint embedding.After three months of treatment, the intervention group suffers from Self-Rating Anxiety Scale (SAS) and Depression Self-Rating Scale (SDS) were significantly lower than the level before self-treatment and intervention group.Li L and others [26] used Beans in Ear Points to improve the anxiety symptoms of diabetic patients,selecting acupoints for endocrine, sympathetic, spleen,kidney, liver, heart, and Shenmen.After fourteen days of treatment, the SAS score of patients was significantly lower than that of the blank control group.Shao HW[27]randomly divided diabetic patients with depression into two groups.The control group took fluoxetine hydrochloride capsules orally, and the intervention group received electroacupuncture at ear points.The current was adjusted according to the patient's tolerance, and the needle was retained for thirty minutes,once a day,six times a week;after three weeks of treatment, the depression score of the intervention group was significantly lower than that of the control group and before self-treatment, while the control group before and after the self-treatment was not statistically significant.After six weeks of treatment, the depression scores of the two groups were significantly lower than before treatment, and the intervention group was significantly better than the control group.It can be seen that auricular therapy can alleviate negative emotions such as anxiety and depression in patients, with rapid onset and lasting effect, and can have a synergistic effect with antidepressants to improve clinical efficacy and promote the recovery of patients'daily life.

Improve sleep quality of diabetic patients

Studies have shown that about half of diabetic patients have sleep disorders, especially insomnia [28].Insomnia can induce anxiety and depression and other negative emotions, and increase the sensitivity of patients to pain.In addition,poor sleep quality can also increase insulin resistance[29],which is not conducive to clinical blood glucose control, and has a serious impact on patient treatment and quality of life.Chen

YH et al.[30] used beans in Ear Points to relieve the symptoms of insomnia in diabetic patients.The main points were sympathetic, Shenmen, subcortical and endocrine,matching points to select heart,kidney,liver,large intestine and hungry points,press three to five times a day, one to two minutes each time, ten to fifteen days as a course of treatment.After three courses of treatment, the total effective rate of insomnia treatment is 97%, and the Pittsburgh Sleep Quality Index (PSQI) is significantly better than blank control group.Li CH et al.[31] performed auricular therapy on diabetic and insomnia patients under the guidance of Ziwu Liuzhu, acupuncture points select Shenmen, sympathetic, anterior, subcortical, spleen,stomach,endocrine,insomnia points,press every day at Si Shi (9:00-11: 00, Taiyin Spleen Meridian of Foot flow time) and Chen Shi (7:00-9:00, Yangming Stomach Meridian of Foot flow time), seven days is a course of treatment.After two courses, the total effective rate of insomnia treatment is 95%, and the PSQI score is significantly better than before treatment.The Meta-analysis by Jiang YT et al.[32]included ten studies.After the analysis, it also showed that Auricular therapy can effectively alleviate the symptoms of insomnia in diabetic patients and improve the quality of sleep in patients.In summary,auricular therapy has a good clinical effect on improving diabetic and insomnia symptoms, and can be used as the first choice for diabetic and insomnia treatment.

Improve constipation symptoms in diabetic patients

Diabetes patients involve the autonomic nerves to varying degrees while the somatic nerves are involved,and then develop gastrointestinal dysfunction,gastrointestinal motility slows down, gastric tone is reduced,emptying time is prolonged,and symptoms of constipation appear [33].Zhu XZ [34] randomly divided 86 patients with diabetes and constipation into two groups.The control group received basic treatment and routine nursing care.On this basis,the intervention group added auricular therapy combined with Acupressure.Among them,Acupressure selects Zhongwan, Tianshu, Zusanli and Sanyinjiao points,and press twice a day; The main acupoints for the auricular therapy are the large intestine,small intestine,rectum, subcortex, and sympathetic, and the matching points are the lung,triple jiao,stomach,spleen,kidney,and endocrine.Press the ear beans five times a day,two minutes per acupuncture point each time;after ten days of treatment, the next course of treatment will be performed after two days of rest; after two courses of treatment, the scores of patients in the intervention group,such as difficulty in defecation,defecation time,abdominal distension, and stool characteristics, were better than those in the control group.Hu J et al.[35]randomly divided diabetic patients who met the criteria for chronic constipation into two groups.The control group was guided by diet and bowel habits; the intervention group added aupressure to the control group, and selected points for the rectum, large intestine,lung,and sanjiao,spleen,constipation points,apply alternately on both ears.After application, press five to six times a day, press the whole ear for two to three minutes each time, and change once every three days; after fourteen days of treatment, the total effective rate of constipation treatment is 60%, which is significantly better than the 23.3% effective rate of the control group,And the improvement of defecation patency was significantly different from the control group (P< 0.05).Chen F et al.[36] used Xiaoke Runchang Decoction combined with electromagnetic wave and auricular therapy to relieve the symptoms of constipation in diabetic patients.The treatment results showed well.The symptoms of constipation in patients were significantly improved compared with those before treatment and the control group.Auricular acupoint therapy is effective in improving the symptoms of constipation in diabetic patients.By selecting acupoints reasonably, it can stimulate the intestinal tract, enhance gastrointestinal peristalsis and secretion of digestive juice through the conduction and reflection of nerves and meridians, thereby facilitating defecation exhaust.

Outlook

Diabetes, as a lifelong incurable disease, not only affects the quality of life of patients, but also brings a great economic burden to the country.The Auricular therapy is based on the holistic view of traditional Chinese medicine,and is gradually accepted by people because of its unique advantages.However, there are still some problems: on the one hand, the breadth and depth of research on Auricular therapy in diabetes is far from enough, there is no uniform standard for the selection of acupoints for diabetes treatment, and it is difficult to repeat interventions in large samples from multiple centers.On the other hand, the current research results are rarely followed up, and there is a lack of long-term effect reporting studies.It is recommended to carry out multi-center and large sample research in the future, pay attention to the standardization of acupoint combination, and need high-quality articles to support the effect of ear acupoint therapy.