The rhino mouse model: the effects of topically applied all-trans retinoic acid and CD271 on the fine structure of the epidermis and utricle wall of pseudocomedones

Abstract

The histological and ultrastructural effects following 3 weeks' topical treatment with two agents (all-trans retinoic acid and a new synthetic retinoid-like substance, CD271) were evaluated on the epidermis and the epithelial wall of the pseudocomedones in rhino mouse skin. The comedolytic effects of these drugs were similar, and consisted of a reduction of the utricular diameter, with normalization of follicular units. Morphological examinations revealed a hyperplastic response with an increase in the number of cell layers of both epidermis and follicular epithelium, and modifications in keratinocyte differentiation. Ultrastructural changes in the epidermis and epithelial wall were observed mainly in the granular and horny layers, with increased desquamation, and a decrease in the cohesiveness of corneocytes. During the first week of treatment, some cutaneous toxic effects were noticed, but they normalized within two weeks. On the other hand, a fine granular material persisted in the intercellular spaces. It is confirmed that the skin of the rhino mouse is a good model for the evaluation of the comedolytic effects of drugs. Moreover, it reveals the specific effects of retinoids on epidermal differentiation. We have demonstrated that topically applied CD271 induces modifications similar to those obtained with all-trans retinoic acid. It is thus concluded that CD271 is a potentially effective anti-acne agent.

Comedolytic effect of topically applied active vitamin D3 analogue on pseudocomedones in the rhino mouse

“…In the rhino mouse skin, the comedolytic effect of topically applied retinoids is characterized by a reduction in utricle diameter 5,29–31 . In the present study, tretinoin reproduced the comedolytic effect as previously reported 29 .…”

“…One of the comedolytic effects of adapalene has been considered to be an increased desquamation of the stratum corneum, 5,6 and tretinoin promoted desquamation in the present study. Unlike tretinoin, we observed orthokeratotic hyperkeratosis rather than desquamation with maxacalcitol.…”

DNA Ploidy Changes in Rhino Mouse Skin Induced by All-Trans Retinoic Acid and Retinol

“…Such an effect is maxi mum after 2 weeks of treatment, leading to disruption of both the stratum comeum layer and the follicular epithelium [4,6]. After 3 weeks of treatment, cells of the comeum lose cohesion, and scaling occurs [4,[7][8][9].…”

Targeting of sebaceous glands by δ‐aminolevulinic acid‐based photodynamic therapy: An in vivo study

“…Remnant sebaceous follicles are histologically reminiscent to retentional human acne lesions such as microcomedones. For that reason, the rhino mouse has extensively been used for comedone studies 14, 15. All procedures were performed according to protocols approved by the Nippon Medical School Subcommittee on Research Animal Care.…”