In animals, especially vertebrates the major type of tissues are nerve, muscle, blood, lymphoid, epithelia and connective tissues. In epithelia tissue, cells are tightly bound together into sheets. Unlike other tissue, epithelia tissue extracellular matrix is almost totally absent and consists of a thin matt called the basal lamina, which under lies the cellular sheet. Epithelia tissue lines all the cavities and free surfaces of animals, and the specialized junctions between the cells enable the epithelia tissue to form barriers to the movement of water, solutes and cells from one body compartment to another. Examples of these cavities and free surfaces include skin, lungs, digestive tract, rectum and the like.
It is readily apparent that epithelia tissue is the first point of contact for a wide range of consumer products. Consumer products, such as those which are topically applied, inhaled, swallowed, ingested, inserted rectally, etc., all initially contact epithelia tissue and either intentionally or unintentionally have an effect on the epithelia tissue. Typically, the effect of the consumer product is difficult, if not impossible, and time consuming to precisely quantify, if such quantification is possible. Furthermore, any assertions made in connection with the benefits and/or comparison to other consumer products on contacting epithelia tissue would face strict legal and regulatory scrutiny not only by various government agencies but also other companies and various special interest groups.
Consequently, there remains the need for methods for evaluating the quantitative changes on epithelial tissue by consumer products and determining the relative benefits of products which affect epithelial tissue.