Ex Vivo Live Full-Thickness Porcine Skin Model as a Versatile In Vitro Testing Method for Skin Barrier Research

Jee-Hyun Hwang,Ki Taek Nam,Nakyum Lee,Haengdueng Jeong,Hye Won Jang,Jeong Jun Han,Kyung-Min Lim,Sumin Hur,Wang Keun Choi,Nahyun Lee

doi:10.3390/ijms22020657

Abstract

Since the European Union (EU) announced their animal testing ban in 2013, all animal experiments related to cosmetics have been prohibited, creating a demand for alternatives to animal experiments for skin studies. Here, we investigated whether an ex vivo live porcine skin model can be employed to study the safety and skin barrier-improving effects of hydroxyacids widely used in cosmetics for keratolytic peels. Glycolic acid (1–10%), salicylic acid (0.2–2%), and lactobionic acid (1.2–12%) were used as representative substances for α-hydroxyacid (AHA), β-hydroxyacid (BHA), and polyhydroxyacid (PHA), respectively. When hydroxyacids were applied at high concentrations on the porcine skin every other day for 6 days, tissue viability was reduced to 50–80%, suggesting that the toxicity of cosmetic ingredients can be evaluated with this model. Based on tissue viability, the treatment scheme was changed to a single exposure for 20 min. The protective effects of a single exposure of hydroxyacids on skin barrier function were evaluated by examining rhodamine permeability and epidermal structural components of barrier function using immunohistochemistry (IHC) and immunofluorescence (IF) staining. Lactobionic acid (PHAs) improved skin barrier function most compared to other AHAs and BHAs. Most importantly, trans-epidermal water loss (TEWL), an important functional marker of skin barrier function, could be measured with this model, which confirmed the significant skin barrier-protective effects of PHAs. Collectively, we demonstrated that the ex vivo live full-thickness porcine skin model can be an excellent alternative to animal experiments for skin studies on the safety and efficacy of cosmetic ingredients.

Highlights

The skin is an organ composed of epidermis, dermis, and subcutaneous tissue.The skin is only millimeters thick, but works as an efficient barrier to protect the body from moisture loss as well as the permeation of exogenous substances such as pathogens [1]and chemicals
Hydroxyacids processed and stained with hematoxylin and eosin (H&E), it was evident that the stratum corneum (SC) was are severely damaged by the application of when
The epidermal barrier is formed by keratinocytes contributing tight junctions and the cornified envelope and by Langerhans cells providing immune functions [17]

Summary

Introduction

The skin is an organ composed of epidermis, dermis, and subcutaneous tissue.The skin is only millimeters thick, but works as an efficient barrier to protect the body from moisture loss as well as the permeation of exogenous substances such as pathogens [1]and chemicals. The skin is an organ composed of epidermis, dermis, and subcutaneous tissue. The skin is only millimeters thick, but works as an efficient barrier to protect the body from moisture loss as well as the permeation of exogenous substances such as pathogens [1]. As increasing attention is given to beauty in modern society, the skin has become one of the leading research topics. Most dermatological research was performed on experimental animals such as mice [2], rats [3], and rabbits. Since the EU announced their animal testing ban in 2013, animal experiments on cosmetics have been prohibited, demanding the development of alternatives to animal experiments for skin research. Several alternative testing methods have been developed for skin studies

Methods

Results

Conclusion