장시간 수화가 표피투과장벽에 미치는 영향

Abstract

[한글]

표피 투과 장벽의 중요한 기능은 우리 몸에서 외부로 수분과 전해질의 손실을 막고, 외부의 물리적, 화학적 손상으로부터 보호하는 것이다. 이러한 장벽의 역할을 하는 각질층은 단백질로 이루어진 각질세포와 각질세포를 둘러싸고 있는 지질로 구성되어 있다. 과수화(overhydration)는 각질층의 팽창과 분리를 야기하며 각질세포간 지질구조의 변화를 일으 키고, 피부 투과 장벽에 손상을 주어 경표피 흡수를 증가 시키는 것으로 생각된다.수화에 의한 각질층의 형태학적 변화와 수화 시간에 따른 장벽기능의 손상을 확인하고 과수화로 인한 피부 장벽의 변화를 관찰하고자 8-12 주된 무모생쥐의 배부에 Hilltop chamber를 이용하여 증류수(pH6)를 노출시켜 24, 36, 48, 72 시간 후 생검하였다. 전자현미경으로 각질층 구조의 보전정도를 알아보기 위해 lanthanum 추적자를 이용하여 표피 투과 장벽의 손상여부를 조사하였고, RuO4 후고정 방법으로 각질세포간 지질의 형태학적 구조를 관찰하였다. OsO4 후고정 방법으로 각질층의 형태학적 특징과 calcium ion cytochemistry를 이용하여 표피 내 칼슘 이온의 분포를 관찰하였다.Nile red 염색상 수화시간이 증가함에 따라 표피 내 각질층의 중성지질 이 감소됨을 관찰하였다. 경표피 수분 손실과 lanthanum 추적자 및 calcium ion cytochemistry 결과 수화 24시간 이후부터 표피 투과 장벽의 손상이 나타남을 알 수 있었다. 24시간 수화 후에는 부분적인 층판소체의 증가를 관찰하였으나 36시간 수화 후에는 더 많은 층판소체가 분비 되었다.RuO4 후고정하여 각질세포간 지질구조를 관찰한 결과 24시간 수화 후 각질층에 확장된 열공이 보였으며, 열공 내부에는 타원형으로 풀어진 모양의 지질 이중막 구조를 관찰하였다. 각질층과 과립층 인접부위는 수화 36시간부터 분리된 소견을 보였고, 내부에서도 동일한 형태의 지질 이중막 구조를 관찰할 수 있었다.이상의 결과로 24시간 이상의 수화는 각질세포간격에 있는 열공과 층상 지질 구조의 변화를 유발한다. 그 결과 표피 투과 장벽을 손상시키고 표피 칼슘 기울기의 소실과 층판소체의 분비를 증가시키는 것으로 생각 된다.

[영문]Among the various functions exerted by mammalian skin, epidermal barrier function is considered as one of the most important ones. The outermost layer of the skin, stratum corneum, is consisted of corneocytes embedded in hydrophobic lipid domain. Epidermal permeability barrier function, which prevents excessive movement of water and other electolytes through the skin, is known as played by this lipid domain in stratum corneum.Hydration of the skin is known to induce structural changes of stratum corneum, and prolonged hydration of skin by lone-term water exposure can result in various dysfucntions due to the structural disorganization. In previous reports about the structural changes, swelling and delamination of the stratum corneum were observed after prolonged water exposure.In this study, hairless mouse model was used for observing the detailed structural changes and corresponding functional changes induced by prolonged water exposure. Hilltop(TM) chamber filled with deionized distilled water (pH 6) was attached to the abdomen of hairless mouse for 24, 36, 48 and 72 hours, respectively.In nile red stain, the amount of epidermal lipid decreased according the hydration time, and lanthanum tracer and epidermal calcium gradient observed by electron microscope also confirmed the abnormalities after 24 hours of water exposure. The epidermal structure was observed by OsO4 post-fixation method and increase of lamellar bodies in stratum corneum-stratum granulosum junction was shown after 24 hours. The RuO4 post-fixed specimen showed many expanded lacunaes between the intercellular spaces in stratum corneum after 24 hours. The separation of stratum corneum-stratum granulosum junction was observed after 36 hours of hydration and disorganized lipid structure was also shown in the stratum corneum.As a conclusion, prolonged water exposure more than 24 hours induces the disruption of epidermal permeability barrier function, and increase of lamellar body secretion. In addition, overhydration results in the increase of lacunaes in stratum corneum, as well as structural disorganization of stratum corneum intercellular lipids. These structural changes can explain the functional abnormalities induced by the prolonged water exposure to the skin.Among the various functions exerted by mammalian skin, epidermal barrier function is considered as one of the most important ones. The outermost layer of the skin, stratum corneum, is consisted of corneocytes embedded in hydrophobic lipid domain. Epidermal permeability barrier function, which prevents excessive movement of water and other electolytes through the skin, is known as played by this lipid domain in stratum corneum.Hydration of the skin is known to induce structural changes of stratum corneum, and prolonged hydration of skin by lone-term water exposure can result in various dysfucntions due to the structural disorganization. In previous reports about the structural changes, swelling and delamination of the stratum corneum were observed after prolonged water exposure.In this study, hairless mouse model was used for observing the detailed structural changes and corresponding functional changes induced by prolonged water exposure. Hilltop(TM) chamber filled with deionized distilled water (pH 6) was attached to the abdomen of hairless mouse for 24, 36, 48 and 72 hours, respectively.In nile red stain, the amount of epidermal lipid decreased according the hydration time, and lanthanum tracer and epidermal calcium gradient observed by electron microscope also confirmed the abnormalities after 24 hours of water exposure. The epidermal structure was observed by OsO4 post-fixation method and increase of lamellar bodies in stratum corneum-stratum granulosum junction was shown after 24 hours. The RuO4 post-fixed specimen showed many expanded lacunaes between the intercellular spaces in stratum corneum after 24 hours. The separation of stratum corneum-stratum granulosum junction was observed after 36 hours of hydration and disorganized lipid structure was also shown in the stratum corneum.As a conclusion, prolonged water exposure more than 24 hours induces the disruption of epidermal permeability barrier function, and increase of lamellar body secretion. In addition, overhydration results in the increase of lacunaes in stratum corneum, as well as structural disorganization of stratum corneum intercellular lipids. These structural changes can explain the functional abnormalities induced by the prolonged water exposure to the skin.