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Revisiting the Pathogenesis of Diabetic Retinopathy from the Perspectives of ‘Xuanfu’ and ‘Luomai’ (Part One)
By Luo Xiangxia, Wu Chengliang, Zeng Min
Expert Introduction
Luo Xiangxia, MD, Chief Physician, Doctoral Supervisor, Director of the Research Department at Gansu Provincial Hospital of Traditional Chinese Medicine, Secretary of the Ophthalmology Party Branch, Fourth Batch of National Excellent Clinical Talent in Traditional Chinese Medicine, Visiting Scholar of the Sixth Batch of Western Light (Tongren Hospital), Flexible Talent Introduced by Lanzhou First People’s Hospital, Fourth Batch of Gansu Province Traditional Chinese Medicine Mentorship Teacher, Member of the Ophthalmology Branch of the Chinese Association of Traditional Chinese Medicine, Member of the Ophthalmology Branch of the Chinese Association of Integrative Medicine, Executive Member of the Diabetes Branch of the Chinese Association for the Promotion of Traditional Chinese Medicine, Director of the Ophthalmology Branch of the Gansu Ethnic Medicine Association, Deputy Director of the Ophthalmology Branch of the Gansu Association of Integrative Medicine, Secretary-General of the Science Association of Gansu Provincial Hospital of Traditional Chinese Medicine, has published over 50 papers, with 3 included in SCI, co-edited 4 textbooks, chief editor of 3, holds 1 software copyright, has presided over 2 national-level fund projects, 3 provincial-level, 6 municipal-level, participated in 13 provincial-level and above research projects, and has led and participated in 10 various scientific and technological progress awards, including 1 second prize for scientific and technological progress in Gansu Province for a project he led.
Introduction
Diabetic retinopathy (DR) is a common vascular complication of diabetes and one of the leading causes of irreversible blindness. It is characterized by retinal vascular leakage, neovascularization, and fibrous proliferation. In Traditional Chinese Medicine (TCM), DR falls under the category of “Xiaoke Neizhang” (internal obstruction due to diabetes), with the disease location in the eyes. The fundamental pathogenesis involves the imbalance of qi, blood, yin, and yang in the organs, characterized by deficiency and excess, and a mixture of both. TCM diagnosis and treatment of DR have unique features, often believed to be caused by prolonged diabetes leading to yin deficiency and qi exhaustion, with long-term illness affecting the collaterals, resulting in blood stasis and obstruction, leading to insufficient nourishment of the meridians. The closure of the ‘Xuanfu’ is the root of all diseases; if the ‘Xuanfu’ is closed and its opening and closing are not regulated, the circulation of qi and blood throughout the body becomes abnormal, leading to stagnation and obstruction of the collaterals. This article attempts to explore the pathogenesis of DR from the perspectives of ‘Xuanfu’ and ‘Luomai’, aiming to provide a theoretical basis for a deeper understanding of DR from the microscopic structural level of TCM.
1. Theories of ‘Xuanfu’ and ‘Luomai’
1.1 Overview of the Theory of ‘Xuanfu’
The term ‘Xuanfu’ first appeared in the Huangdi Neijing (Yellow Emperor’s Inner Canon), which states: “The so-called Xuanfu refers to the sweat pores,” indicating the sweat pores of the skin and the interstitial spaces. The Jin Dynasty physician Liu Hejian believed that ‘Xuanfu’ is a microscopic structure that permeates all organs and meridians. In the Suwen (Plain Questions) of Huangdi Neijing, it is mentioned: “The sweat pores of the skin are the openings for the outflow of qi and fluids, also known as the ‘qi gate’… ‘Xuanfu’ contains everything… it is the pathway for the entry and exit of qi.” The physiological functions of ‘Xuanfu’ can be summarized as regulating the flow of qi and fluids, permeating qi and blood, and transporting the spirit. During the circulation of qi and fluids, ‘Xuanfu’ acts as a “control valve” and “opening and closing pivot,” regulating the circulation and distribution of qi, blood, and body fluids throughout the organs and meridians. The key to ‘Xuanfu’ is its opening and closing; it should not be obstructed. Proper opening and closing are necessary for its normal physiological function. If ‘Xuanfu’ is excessively open, the righteous qi may easily disperse outward, leading to a loss of qi and the leakage of essential substances. Conversely, if ‘Xuanfu’ is closed and obstructed, various diseases may arise.
1.2 Overview of the Theory of ‘Luomai’
‘Luomai’ is first recorded in the Huangdi Neijing, Ling Shu (Spiritual Pivot), which states: “The meridians are internal, while the branches that spread horizontally are the collaterals, and the branches of the collaterals are the ‘Sun’.” According to their location, the collaterals are distributed throughout the body, connecting internally to the organs, muscles, and bones, and externally to the orifices, muscles, and skin. Functionally, the collaterals that transport qi are called ‘qiluomai’, while those that transport blood are called ‘maimai’, elucidating the characteristic of collaterals as “pathways.” The Huangdi Neijing, Ling Shu states: “At the joints, there are 365 meeting points, which are the collaterals that permeate and nourish the joints,” thus, the collaterals can also permeate qi, blood, and body fluids, harmonizing and regulating the circulation of qi, blood, and body fluids throughout the body, ensuring that the five organs and six bowels, as well as the nine orifices, are adequately nourished.
1.3 The Relationship between ‘Xuanfu’ and ‘Luomai’
TCM posits that both ‘Xuanfu’ and ‘Luomai’ are microscopic structures that maintain the orderly operation of qi, blood, and body fluids throughout the body, with no organ being without them. The two are closely related and accompany each other. However, they differ structurally; ‘Xuanfu’ embodies the characteristic of a “gateway,” while ‘Luomai’ represents the characteristic of a “pathway.” The two structures complement each other; ‘Xuanfu’ is essentially the “gateway” for the opening and closing of the ‘Luomai’ system. The ‘Xuanfu and Luomai’ system jointly participates in the formation of the body’s microscopic structure. Functionally, the normal opening and closing of ‘Xuanfu’ ensures the orderly flow of qi, blood, and body fluids in the collaterals, while the nourishing function of the collaterals can also support ‘Xuanfu’, ensuring the normal operation of its opening and closing. The two are mutually supportive, maintaining the orderly circulation of qi and blood throughout the body. Pathologically, while they differ, there are interconnections. If ‘Xuanfu’ is excessively open, it can easily deplete the qi and blood of the collaterals, leading to a deficiency of qi and blood over time. Conversely, if ‘Xuanfu’ does not open and close adequately, the flow of qi and blood in the collaterals becomes obstructed, causing the collaterals to compensate for the mismanagement of ‘Xuanfu’, further developing into ‘Xuanfu’ obstruction and collateral stasis, ultimately leading to internal wind movement. A deficiency of qi and blood in the collaterals cannot nourish ‘Xuanfu’, while stasis of qi and blood in the collaterals leads to ‘Xuanfu’ being closed and unused. Prolonged closure results in poor circulation of qi and blood, leading to the internal generation of blood stasis, phlegm-dampness, and turbid toxins, which will inevitably lead to abnormal opening and closing functions of ‘Xuanfu’. Therefore, whether it is a collateral disease or a ‘Xuanfu’ disease, or vice versa, both will ultimately lead to the disease of both, further affecting the normal physiological functions of the body.
2 Understanding Eye Diseases from the Theoretical Basis of ‘Xuanfu’ and ‘Luomai’
The author believes that the microscopic structures of ‘Xuanfu’ and ‘Luomai’ are present in all organs, with the eyes being particularly significant. The ‘gateway’ of ‘Xuanfu’ and the ‘pathway’ of ‘Luomai’ play important roles in the physiology and pathology of the eyes.
2.1 The Theory of ‘Xuanfu’ in the Eyes
In the Ming Dynasty, physician Lou Ying discussed eye diseases based on Liu Wansu’s theory of ‘Xuanfu’. In the Yixue Gangmu (Medical Compendium), he pointed out: “Blindness and deafness… are all due to the closure of the ‘Xuanfu’, as the eyes govern the abundance of qi and blood, thus the ‘Xuanfu’ benefits from it, allowing for the entry and exit to be clear and bright; if deficient, the ‘Xuanfu’ cannot open and close, leading to dimness.” This indicates that either qi and blood stagnation or deficiency can lead to the closure of ‘Xuanfu’, resulting in unclear vision. Modern ophthalmologist Chen Dafu combined the six meridians with the theory of ‘Xuanfu’, proposing theories such as “Liver Meridian Xuanfu” and “Shaoyin Meridian Luomai”, revealing the close relationship between the six meridians and ‘Xuanfu’. Additionally, Pang Zanxiang proposed the theory of “many stagnations in eye diseases”, believing that “opening the ‘Xuanfu’ and dispersing stagnation” is an important principle in treating eye diseases. Zhuang Zengyuan further developed the theory of ‘Xuanfu’, forming the academic thought of “the importance of ‘Xuanfu’ in eye diseases” and using methods to open ‘Xuanfu’ to treat internal and external eye diseases. The Encyclopedia of Traditional Chinese Medicine: Ophthalmology first explained ‘Xuanfu’: “The ophthalmic ‘Xuanfu’ is the pathway for the rise and fall of essence, qi, and blood; if ‘Xuanfu’ is obstructed, the eyes lose nourishment and become dim; if ‘Xuanfu’ is closed, the eyes lack nourishment and the three lights are extinguished.” Through the exploration and development of generations of physicians, the theory of ‘Xuanfu’ in ophthalmology has been continuously developed and improved, making it an important foundational theory guiding clinical work in ophthalmology. As a fundamental structure present throughout the body, ‘Xuanfu’ has the characteristics of widespread distribution, fine structure, and the importance of opening and avoiding closure, serving as the gateway for the rise and fall of qi, blood, and body fluids, as well as the spirit and defensive qi. When it is open, essence, qi, blood, and body fluids can adequately nourish the eyes, allowing for normal vision. Once the opening and closing of ‘Xuanfu’ is mismanaged and obstructed, the internal circulation of essential substances becomes abnormal, failing to maintain normal rise and fall, leading to insufficient nourishment of the eyes, resulting in eye diseases. Thus, the closure of ‘Xuanfu’ and mismanagement of its opening and closing are fundamental pathologies for many eye diseases.
2.2 The Theory of ‘Luomai’ in the Eyes
The Huangdi Neijing, Suwen states: “All meridians belong to the eyes,” indicating the close relationship between the eyes and the meridians. The collaterals are branches of the meridians. The Ling Shu states: “The meridians are internal, while the branches that spread horizontally are the collaterals, and the branches of the collaterals are the ‘Sun’.” The eye collaterals are the extensions of the collaterals in the eyes, serving to permeate qi and blood and connect to the organs. Qi, blood, and fluids (body fluids) travel together in the eye collaterals, with qi driving blood and fluids to circulate within the eye collaterals. Blood permeates the collaterals and becomes body fluids, while body fluids entering the collaterals become blood, thus the eye collaterals serve as a hub for the interconnection of qi, blood, and body fluids. The Zhengzhi Zhunjing states: “Internally, there are large collaterals of six… and eight collaterals in the middle… externally, there are numerous fine collaterals, all connecting to the brain, linking the organs, and facilitating the circulation of blood and qi to nourish the eyes,” indicating that the collaterals are pathways connecting the five organs and six bowels with the eyes, and the relationship between eye diseases and collateral diseases is significant and close. Pang Zanxiang believes that only when the qi and blood in the eye collaterals are smooth can the essence and qi of the organs adequately nourish the eyes, establishing a material foundation for clear vision. Zhang Minglian, based on the theory of collaterals and years of clinical practice in ophthalmology, proposed the theory of eye collaterals, asserting that stagnation of the eye collaterals and obstruction of qi and blood are important mechanisms for the onset of eye diseases, with heat, toxins, phlegm, dampness, stagnation, and deficiency being the main causes.
References
See the Chinese Journal of Traditional Chinese Medicine Ophthalmology, 2022, Volume 32, Issue 12, “Expert Forum”
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