Intercellular stroma includes fibers, matrix, and fluid substances (tissue fluid, lymph fluid, blood plasma), etc. There exists interstitium between cells and cells. Interstitium is the substance produced by cells that does not have the form and structure of cells, which includes fibers, matrix, and fluid substances (tissue fluid, lymph fluid, and plasma), etc. Interstitium is also known as the substance between cells, which is the substance that exists between cells that is different from the cells in one or several ways. These substances included in the intercellular matrix, such as tissue fluid, fiber, plasma, etc., play a supportive, protective, connective and nutritive roles for the cells, and participate in constituting the microenvironment for cell survival, and the intercellular matrix is the living environment of the cells.