Effects of alkaline on horny layer cellularity

Area of Science:

• Dermatology and skin physiology.
• Biomaterials science and tissue engineering.

Background:

• The stratum corneum (Str. corneum) is the outermost layer of the epidermis, providing a barrier function.
• Understanding the effects of chemical agents on the stratum corneum is crucial for various applications, including skincare and wound healing.

Purpose of the Study:

• To investigate the microscopical changes in plantar stratum corneum upon immersion in alkaline solutions.
• To elucidate the mechanism of alkaline-induced cell loss in the stratum corneum.

Main Methods:

• Utilized an in vivo test system with unexcised guinea pig hind feet skin.
• Employed FITC-staining method for microscopic analysis of stratum corneum changes.
• Compared cell loss rates under conditions of repeated superficial cell removal versus permanent immersion.

Main Results:

• Alkaline exposure (KOH) induced immediate swelling of outer stratum corneum cell layers.
• Maximal swelling was followed by progressive cell separation and layer-by-layer loss.
• Repeated removal of treated superficial cells resulted in a higher and more constant rate of cell loss compared to permanent immersion.
• The buffering capacity of the stratum corneum's outer layers was identified as a rate-limiting factor in alkaline-induced cell loss.

Conclusions:

• Alkaline solutions induce significant structural alterations in the stratum corneum, leading to cell swelling and separation.
• The rate of cell loss is influenced by the removal of superficial layers, suggesting a role for buffering capacity.
• Findings provide insights into the interaction of alkaline substances with skin barrier components.