The Similarity Between Cellular Edema in Western Pathology and the Spleen-Deficiency, Excess-Dampness Pattern in TCM

Cellular edema (also called hydropic degeneration or watery change) is the earliest pathological change in cell injury, arising from impaired function of the mechanisms that regulate cell volume and cytoplasmic ion concentration. Cellular edema is an important topic in Western pathology; its essence is the excessive accumulation of water in organelles, cytoplasm, the nucleus, or the interstitium.

Cellular edema is a reversible form of cell injury. Many causes can produce it—hypoxia, infection, poisoning, nutritional disorders—and it is common in the parenchymal cells of organs such as the heart, liver and kidneys. Tissues with cellular edema, viewed under a microscope, usually show diffuse cell swelling, pale cytoplasm, and a slightly enlarged nucleus. In severe cases, cells swell markedly into a balloon shape, a condition called ballooning degeneration. To the naked eye, the affected organ is enlarged, its capsule tense, its edges blunted, its color paler, and it looks cloudy as if boiled in water.

The mechanism of cellular edema is that mitochondria in the body are damaged, leading to reduced ATP production. ATP is also called the "energy currency," and many reactions in the body require ATP to supply energy. So if ATP production falls, some important biochemical reactions in the body are affected. The first to suffer is dysfunction of the cell-membrane sodium pump; when the sodium pump cannot operate normally, sodium inside the cell inevitably cannot flow out normally. When intracellular sodium concentration is too high, maintaining osmotic balance across the cell membrane necessarily leads to excessive accumulation of water inside the cell, producing cellular edema.

At the same time, the sodium pump is also key to generating the action potential, and nerve conduction depends on normal sodium-pump function. After cellular edema, action potentials cannot fire normally, nerve conduction is affected, and a person's responses become sluggish.

Western cellular edema and the TCM spleen-deficiency, excess-dampness pattern have much in common. According to TCM's zang-xiang (visceral manifestation) theory, the spleen governs the transportation and transformation of water-dampness; when spleen deficiency fails to transport, the body's water metabolism becomes disordered, with internal retention of damp turbidity, leading to symptoms such as abdominal distension, fatigue, edema, virtual puffiness, a thick greasy tongue coating, and pitting when the skin of the limbs is pressed.

We often hear people say they "gain weight just by drinking water"; such people belong to this type. From the TCM perspective, such people have spleen deficiency with excess dampness; from the Western perspective, they have developed hydropic degeneration.

How does TCM treat spleen-deficiency excess-dampness patients? Generally, formulas that fortify the spleen and drain dampness are used; the most typical representative is Sijunzi Tang (Four-Gentleman Decoction). Sijunzi Tang consists of Renshen (Ginseng), Baizhu (Atractylodes macrocephala), Fuling (Poria) and Gancao (Licorice); TCM holds that Renshen, Fuling and Gancao all belong to the spleen-fortifying qi-tonifying category.

Modern pharmacological research has found that one of the greatest functions of ginsenosides is regulating mitochondrial function. Besides ginseng, the TCM qi-tonifying herbs Huangqi (Astragalus), Baizhu (Atractylodes), Gancao (Licorice) and Xiyangshen (American ginseng) actually all have mitochondrion-regulating functions. Since the mechanism of cellular edema is damage to the body's mitochondria, it is no surprise that these Chinese medicines can reverse cellular edema. Baizhu and Fuling also have strong diuretic effects; TCM says they "drain dampness," and the excess water accumulated inside cells can be expelled from the body under the action of Baizhu and Fuling.

When we combine Western pathology with a study of TCM spleen theory, we find that much of TCM's zang-xiang theory is actually quite scientific.