Objective

The skin separates the body from the outside world, and plays an important role in maintaining homeostasis by acting as a physical barrier and retaining skin moisture. However, the skin is susceptible to various internal and external factors, and numerous diseases arise in the skin. In particular, damage in the superficial stratum corneum is known to induce various dermatological diseases, and in both dogs and humans, allergic diseases have been shown to damage the stratum corneum. One mechanism for such damage is the alteration of lipids that exist among and on the surface of cells in the stratum corneum, which play an important role in barrier and moisture-retention functions. However, the characteristics of the canine stratum corneum have not been sufficiently investigated. In the present study, in an attempt to elucidate the characteristics of the canine stratum corneum, the structure of the superficial stratum corneum was investigated both morphologically and physiologically.

Materials & Methods

Samples were collected by the tape strip method and analyzed by light and electron microscopy.

Results

The results showed that, in the canine stratum corneum, there was a lipid layer containing numerous free cells and melanin granules. In addition, the moisture retention function of the body surface was investigated using Sukicon (Electrical measurement), and the results showed that both the moisture retention function of canine skin and its electrical conductivity were low. A water-loading test also revealed that the water repellency of the canine skin was high. The above data indicates that the structure of the superficial layer of the canine skin is mostly similar to that of human skin, but in the lipid layer, there are many more cellular and granular components, thus resulting in high water repellency and low conductivity.

Conclusion

These findings suggest that the canine stratum corneum has physiological functions related to biological defense mechanisms that are unique to dogs. Therefore, it is extremely important to determine changes in the characteristics of the superficial stratum corneum when assessing the pathology of dermatological diseases in dogs and the effectiveness of subsequent treatment.