Core acupoints of acupuncture for hyperplasia of mammary gland:a network analysis

Bao-Min Dou,Yuan-Yuan Sun,Tian-Yi Zhao,Qian-Nan Jia,Jiang Liu,Bo Chen,Yi Guo,2＊

1Experimental Acupuncture and Moxibustion Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin 301617,China. 2College of Traditional Chinese Medicine,Tianjin University of Traditional Chinese Medicine,Tianjin 301617,China.

Abstract

Keywords: Hyperplasia of mammary glands (HMG), Acupoints compatibility, Complex network analysis,Traditional Chinese medicine.

Highlights

The study established the acupoints database and complex network of acupoints compatibility for acupuncture treatment of hyperplasia of mammary gland (HMG). The results found that the main acupoint compatibility of acupuncture therapy for HMG was the local and remote acupoints, and the selected core acupoints for acupuncture treatment of HMG were Danzhong (CV 17),Wuyi (ST 15), Zusanli (ST 36)and Jianjing(GB 21).

Figure 4 The correlation analysis of acupoint network connection. The left figure is the network diagram of all acupoints, and the right figure is the network diagram of k-core ≥10 acupoints. The darker and wider the edge is,the larger the correlation degree is.

Background

Hyperplasia of mammary gland (HMG) is a benign breast disease caused by the abnormal development and degeneration process of the mammary gland[1].It occurs among middle-aged women with high frequency [2]. There is a study shows that the morbidity of breast diseases in Chinese women is up to 25.5%, among which the number of patients with breast hyperplasia is up to 78.6%, which has a substantial morbidity in healthy population [3]. In recent years, under the influence of work and life pressure, women often have endocrine dysfunction,leads to the increasing morbidity and canceration rate of HMG year by year, ranking the first among urban women with high morbidity of diseases [4-6].Therefore, the treatment of this disease has important clinical value[7,8].

HMGs in the traditional Chinese medicine called“Ru Pi”, the word first recorded in the ancient book of Chinese medicine Zhong Zang Jing (in the scriptures)written by Tuo Hua around 200 C.E. [9]. Another ancient book of Chinese medicine Wai Ke Huo Ren Ding Ben, first defined “Ru Pi” as a breast lump,written by Ju-Zhong Gong in the Ming Dynasty (1630 C.E.)[10].The treatment of HMG by acupuncture was first recorded in the ancient book of Chinese medicine Jia Yi Jing of Fu-Mi Huang in Jin Dynasty (282 C.E.).In ancient times, there were more than 30 books recorded acupuncture for the treatment of HMG, such as Zhen Ci Da Cheng, Qian Jin Yao Fang [11]. The main acupoints are Huangmen(BL 51),Zhongji(RN 3)and so on. Modern articles on the treatment of HMG by acupuncture first appeared in the late 1950s, but it was until the late 1970s that they attracted the attention of acupuncture researchers again [12]. In the past 40 years, most clinical studies and systematic evaluations have confirmed the clinical efficacy of acupuncture in the treatment of mammary hyperplasia [13-16].Mechanism research has also made some progress[17-19]. They conducted relatively in-depth clinical and experimental studies and achieved certain achievements. As a commonly used method to treat this disease, acupuncture has the characteristics of quick analgesic effect, economy,safety,no side effects and so on.

The combination of acupoints plays an important role in acupuncture therapy, and it is the key factor to determine clinical curative effect [20]. Compared with the frequency and association rule analysis of common methods in data mining, complex network analysis,with its unique scale-free and small-world characteristics [21], can more dynamically reflect the core acupoints compatibility. At present, it is widely used in the research on acupoint compatibility of diseases and acupoint syndrome [22-25]. Therefore,this study adopted complex network topological structure technology to preliminarily explore the optimal point selection for acupuncture treatment of HMG,which was closer to the clinical practice.

Materials and methods

Establishment of acupoint prescription database

Literature sources.The databases of CNKI, VIP,WanFang and PubMed were retrieved from the inception to 25 October 2019.Retrieval strategies were as follows: (acupuncture or electric acupuncture or hand needle or filiform needle) and (hyperplasia of mammary gland or cyclomastopathy or hyperplastic disease of breast or mammary gland proliferation or Ru pi).

Literature inclusion criteria.(1) Literature types:randomized controlled trial, non-randomized controlled trial and case report. (2) The diagnostic criteria for “hyperplasia of mammary glands” are clearly described in the literature according to the criteria for diagnosing HMGs [26]: ①vague pain or distending pain of the breast mostly on both sides or sometimes on one side, and the pain may be aggravated before menstruation or when the emotion fluctuates; ②breast masses on both sides or on one side vary in size, soft and tenacious or hard and tenacious with unclear border, and with tenderness but no adhesion; ③ ultrasonic examination may show expanded ducts and thickened mammary glands; ④roentgenogram of molybdenum target may show even and denser shadow of the mammary glands.

Literature exclusion criteria.(1) Repeated published literature in the database and literature with repeated data;(2)animal experiments or non-clinical studies;(3)literature review or theoretical discussion (no case observation and statistical analysis); (4) meta-analysis of literature on the treatment of breast hyperplasia, and systematic evaluation; (5) acupuncture or electropuncture combined with other therapies, using acupuncture or electropuncture but without acupoint selection;(6)HMGs with other diseases.

Specification of acupoint name.According to the international standard of acupuncture points promulgated by the World Health Organization in 1991[27] and the international standard of the People's Republic of China: name and location of acupoints(GB/t12346-2006) [28], this study standardized the names of acupoints involved.

Prescription extraction.Two researchers worked together to complete the extraction work. One researcher recorded the literature acupoint prescription into the “acupoint compatibility law database of acupuncture for HMG”, and the other one checked it.Entries in the acupoint database are as follows: basic information of literature, intervention measures, single acupoint or matching acupoints, name of acupoint,method of acupoint matching, meridian alignment of acupoint,attribute of specific acupoint,etc.

Method of matching acupoints.The method of matching acupoints for main and secondary acupoints was designed by ourselves according to acupuncture and moxibustion prescription [29, 30] and Qijie (Qi street) theory (Qijie theory is one of the important components of traditional Chinese medicine meridian and collateral system, it is the shortcut for the communication from the exterior to the interior and for the transverse connection) [31]. The main method of matching acupoints including local matching acupoints(the selected acupoints are located at the lesion site),far matching acupoints (the selected acupoints are far away from the lesion site), local-remote acupoints(some of the selected acupoints are at the lesion site and some are far away from the lesion site).Secondary matching acupoint method including upper and lower matching acupoints (the selected acupoints are partly above and partly below the waist), front and rear matching acupoints (the selected acupoints are partly ventral and partly dorsal), the same meridian acupoint(some selected acupoints are located in the same meridians), two meridians with the exterior-interior relationship acupoints (some selected acupoints are located in two meridians with the exterior-interior relationship), meridians of the same name matching acupoints (the selected acupuncture points are located in the name-same meridians of the hand and foot).

Analysis methods

Establishment of complex network.Converts the text information in the data source to the vector form,marked with name of acupoints as the feature vector,to extract the feature vector and input to the structured acupoints in prescription T/F the fact table, and then import it into data mining software SPSS Modeler 18.0.Create the association rule program flow, run and output the node acupoints with association and their weight value.The output node represents the acupoint,and the connection between nodes represents the weight. The output nodes were numbered, and combined with edge weights, node list and edge list were created and imported into Gephi complex network analysis software. The central aggregation distribution model of “Fruchterman Reiehold”algorithm was selected for modeling, and core acupoints were analyzed by k-core method.

Characteristics of complex network topology.The topological structure of acupoint prescription network,including average degree and degree distribution,clustering coefficient,average path length and network diameter, was analyzed by Gephi analysis function of complex network processing software[32-34].

Analysis of node degree centrality in complex networks.The performance of node degree center directly reflects the importance of nodes in the network[35], and explores core node acupoints by using the node attribute analysis function of complex network.

Association rule analysis.Carma algorithm [36] in SPSS Modeler 18.0 software was used to construct the association rule model to obtain the confidence,support and improvement of the compatibility of acupoints (nodes) [37]. Combined with the above analysis results, the compatibility law of acupoints for acupuncture treatment of HMG was extracted.

Results

Included literature

A total of 1,158 literature were retrieved,including 186 references according to the inclusion criteria, 456 references were excluded according to the exclusion criteria,and 104 references were finally included in the effective literature. According to the case report literature, several acupoint prescriptions can be listed.Besides,the acupoint applied in each document is used as an acupoint prescription. There is a total of 106 prescriptions(Figure 1).

Frequency analysis results

Acupoint matching methods.A total of 106 acupoint prescriptions were included, among which 7 were single-acupoint prescriptions, accounting for 6.6% of the total number of prescriptions, and 99 were pot-matching prescriptions, accounting for 93.4% of the total number of prescriptions.

The main method of matching acupoints is local-remote matching acupoints. There are a total of 99 prescriptions for pot-matching acupoints, among which there are 84 ones for local-remote matching acupoints, accounting for 84.84% of the total, 13 ones for local matching acupoints,accounting for 13.13%of the total, and 2 ones for remote matching acupoints,accounting for 2.03% of the total (Figure 2a). The secondary method is upper-lower matching acupoints and front-rear matching acupoints(Figure 2b)

High frequency acupoints.According to the frequency analysis of acupoints (Table 1), the acupoints with the most frequent occurrence are Danzhong (CV 17), Wuyi (ST 15), Zusanli (ST 36),Jianjing(GB 21)and Rugen(ST 18).

Acupoints-channel tropism.Analysis of the belonging meridians of all acupoints in the database(Table 2). For the treatment of HMG, most of the points were in the Stomach Meridian, followed by Conception Vessel and Liver Meridian.

Complex network analysis results of acupoints compatibility

Acupoints correlation analysis.The T/F table was imported into SPSS Modeler 18.0 for correlation analysis of acupoints. The more times the acupoints were combined,the thicker the connection between the acupoints and the closer the relationship between the two nodes. As can be seen from the Figure 3,Danzhong (CV 17) and Zusanli (ST 36), Danzhong(CV 17) and Wuyi (ST 15), Jianjing (GB 21) and Tianzong (SI 11), Jianjing (GB 21) and Wuyi (ST 15),Jianjing(GB 21)and Taichong(LR 3)have the highest correlation degree.

Acupoint association rules.The T/F table was imported into SPSS software. After several tests, the minimum support degree was set at 20% and the minimum confidence degree was set at 80%.A total of 14 association rules were obtained. The 14 association rules show that Danzhong (CV 17), Zusanli (ST 36),Jianjing (GB 21), Wuyi (ST 15), Tianzong (SI 11),Ganshu(BL 18)have strong correlation(Table 3).

Acupoint network connection.Through the analysis of SPSS Modeler correlation program, 64 node acupoints and 492 edge weights were finally derived.By importing the data into Gephi for operation, it was found that the average degree of the complex network model was 11.89 (that is, each acupoint was compatible with 11.89 other acupoints on average).The average clustering coefficient is 0.38 (between 0 and 1, indicating good connectivity performance among nodes of the complex network). The average path length is 1.55 and the network diameter is 3 (the shortest distance of any two acupoints in the network is 1 edge and the longest distance is 3 edge, represents the global characteristics of the network small-world network). After k-core ≥ 10 screening, complex network diagram of acupoints compatibility in Figure 4 shows that the core acupoints are Danzhong (CV 17),Zusanli (ST 36), Wuyi (ST 15), Taichong (LR 3),Jianjing (GB 21), Ganshu (BL 18), Tianzong (SI 11),Qimen (LA 14). The darker and wider the edge is, the larger the correlation degree is.

The degree centrality of acupoints.The average degree of the acupoints in the complex network is 11.89,so the acupoints greater than the average degree value are selected as the degree center of the complex network.There are 16 acupoints in the degree center in Table 4,among which the highest degree acupoints are Danzhong (CV 17),Taichong (LR 3), Zusanli (ST 36),Sanyinjiao (SP 6), Rugen (ST 18), Hegu (LI 4), Wuyi(ST 15).

Figure 1 The process of literature screening

Figure 2 The methods of matching acupoints.a,The main method of matching acupoints.b,The secondary method of matching acupoints.

Figure 3 The correlation analysis of acupoints.The left figure is the connection diagram of all acupoints,and the right figure is the connection diagram of frequency ≥10 acupoints.

Figure 4 The correlation analysis of acupoint network connection. The left figure is the network diagram of all acupoints, and the right figure is the network diagram of k-core ≥10 acupoints. The darker and wider the edge is,the larger the correlation degree is.

Table 1 Frequency analysis of acupoints

Table 2 Analysis of the belonging meridians of all acupoints in the database

Table 3 The correlation analysis of acupoint association rules

Table 4 The degree centrality of acupoints

Discussion

Through data mining and complex network analysis, it was found that the core acupoints for the treatment of HMG with acupuncture were Danzhong (CV 17),Wuyi (ST 15), Zusanli (ST 36) and Jianjing (GB 21).The combination of them could be regarded as the core acupoint prescription commonly used in clinical treatment of HMG. The meridians of these acupoints belong to the Stomach Meridian of Foot-Yangming,Conception Vessel and Liver Meridian of Foot-Jueyin.HMG is located in the breast, Danzhong (CV 17),Wuyi (ST 15) and Jianjing (GB 21) are all located in the chest and back, belonging to local acupoints selection,while Zusanli(ST 36)is located in the lower limbs, belonging to the far acupoint selection,reflecting the important rules of acupuncture treatment of HMG with acupoints: local-remote acupoints,upper-lower acupoints and front-rear acupoints.

Danzhong (CV 17) is located between the two breasts and belongs to the Conception Vessel. The subcutaneous tissues of Danzhong (CV 17) have perforating branches of the arteriovenous in the breast,and have the anterior cutaneous branches and medial branches of the 4th intercostal nerve. Acupuncture of this acupoint may affect the physiological function of the breast by stimulating blood vessels and nerves near it. Wuyi (ST 15), which belongs to the Stomach Meridian of Foot-Yangming, it located in the chest,the pectoralis is distributed under it, and the acupuncture reduce the pressure on blood vessels, improve the blood circulation of the mammary gland, excrete inflammatory secretions and metabolites, and improve symptoms accordingly [38]. Wuyi (ST 15) is distributed in the upper thoracic medullary segment dominated area or the similar segment, which lays the physiological basis for the treatment of breast hyperplasia with the acupoints in the thoracic medullary segment dominated area [39]. Zusanli (ST 36) is the acupoint of Stomach Meridian of Foot-Yangming.

From the perspective of western medicine, breast hyperplasia is mainly caused by endocrine function turbulence-the imbalance of estrogen and progestin[40], while Zusanli (ST 36) has a certain regulation effect on the endocrine system function [41]. The nerve branch, the branch of microvascular and lymphatic branches is very rich in Zusanli(ST 36)[42],some studies have found that stimulated the acupoint area could start the the whole hormone regulation of the nerve-endocrine-network by nerve, blood or lymph eventually [43]. Jianjing (GB 21), acupoint of Gallbladder Meridian of Foot-Shaoyang, is an experiential acupoint of HMG, which is the intersecting point of the Hand-Shaoyang meridian,Foot-Shaoyang meridian and Yangming meridian.And the meridians that it crosses all follow the breast, so acupuncture in Jianjing (GB 21) regulate various meridians. Guo [45] found that acupuncture in Danzhong (CV 17), Wuyi (ST 15), Zusanli (ST 36) of the HMG model rats could reduce the contents of estradiol, prolactin and follicle-stimulating hormone,and increase the secretion level of ovarian progesterone, luteinotropin and testosterone. The correlation between the sex hormones in HMG model rats has a certain regulatory effect, can correct the disorder of the sex hormone levels in the rats. Xie's study [46] found that acupuncture on the Danzhong(CV 17), Taichong (LR 3), Zusanli (ST 36) of the HMG model rats could reduce the number of acinus of the breast and their secretions, reduce estradiol in the serum and increase progesterone in the serum, at the same time, reduce the mRNA of estrogen receptor and progesterone receptor in the breast tissue, making the breast tissue less sensitive to estrogen and progesterone.So the mechanism of acupuncture in treating this disease is mainly to adjust the endocrine function of the disorganized hypothalamic-pituitary-ovarian axis,reduce the sensitivity of breast tissue to estrogen, thus inhibiting the replication of proliferating cells, slowing down the rate of cell proliferation, so that the proliferating breast tissue can return to normal[47].

At present, acupuncture therapy has unique advantages in the treatment of HMG, but the standards of acupuncture point selection and efficacy are not unified.There are still some shortcomings in this study.The number of literature is limited, the classification and selection of acupoints have not been sorted out,and the quality of literature has not been evaluated. It is expected that further analysis can be conducted in the following studies.

Conclusion

The compatibility law of acupoints for acupuncture treatment of HMG are mainly local-remote acupoints and upper-lower acupoints. The complex network analysis shows that the core acupoints are for acupuncture treatment of HMG were Danzhong (CV 17), Wuyi (ST 15), Zusanli (ST 36) and Jianjing (GB 21). The meridians of these acupoints belong to the Stomach Meridian of Foot-Yangming, Conception Vessel and Liver Meridian of Foot-Jueyin.