Applied Microscopy

Korean Society of Microscopy (한국현미경학회)
권호 표지

Immunocytochemistry of Metallothionein Expression in Developing Rat Liver

발생중인 흰쥐 간에서의 Metallothionein 발현에 관한 면역세포화학적 연구

  • Oh, Seung-Han (Department of Life Science, College of Natural Sciences, Soonchunhyang University) ;
  • Ahn, Young-Mo (Department of Life Science, College of Natural Sciences, Soonchunhyang University) ;
  • Shin, Kil-Sang (Department of Life Science, College of Natural Sciences, Soonchunhyang University) ;
  • Kim, Wan-Jong (Department of Life Science, College of Natural Sciences, Soonchunhyang University)
  • 오승한 (순천향대학교 자연과학대학 생명과학부) ;
  • 안영모 (순천향대학교 자연과학대학 생명과학부) ;
  • 신길상 (순천향대학교 자연과학대학 생명과학부) ;
  • 김완종 (순천향대학교 자연과학대학 생명과학부)
  • Published : 2004.09.01
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Abstract

Metallothionein (MT) is a family of ubiquitous, low molecular weight (6-7 kDa), cysteine-rich protein with a high affinity to metal ions and has no aromatic amino acids and histidine. Some of the known functions of MT include detoxification of heavy metals and alkylating agents and neutralization of free radicals. Also, this protein may affect a number of cellular processes including gene expression, apoptosis, proliferation and differentiation. But, its actual functions are still not clear. The present study was undertaken to examine immunocytochemically the localization of MT in developing rat liver. On the day 11 of gestation, the fetal rat liver has already been formed and contained numerous oval cells with high nuclear cytoplasmic ratio, which were the progenitors of hepatic parenchymal cells, but no reaction products of MT were detected at this time. And then, positive reactions against MT started to appear predominantly in the parenchymal cells of liver from the 13th day after gestation. Reaction products, immunogold particles or brown coloration, were localized at both the nucleus and the cytoplasm of the parenchymal cells, except mitochondria. The intensity of this reaction gradually increased, and exhibited the strongest at birth. The intensity of MT staining and immunogold labelling diminished with growth, and by the 15th day after birth weak positive reaction was observed in the cells. In brief, positive reactions for MT were observed in the oval cells and the parenchymal cells during fetal stage, meanwhile they were present only in the parenchymal cells after birth. The present results suggest that MT possibly involves parechymal cell proliferation and differentiation through the storage or the supply of various metal ions in the developing rat liver.

메탈로사이오닌 (metallothionein: MT)은 시스테인(cysteine)이 다수 포함되어 있고, 저분자량인 단백질로서 중금속이온이나 다양한 세포 독성 인자에 의해 유도되며, 최근 발암과정 (carcinogenesis)이나 혹은 세포분화와 연관하여 활발하게 연구가 이루어지고 있다. 본 연구는 흰쥐를 수정시킨 후 발생과정 또는 출생 후 성장과정 단계에서 태아와 신생 흰쥐의 간 조직 및 세포내 MT의 분포 양상을 조사하고자 하였다. 흰쥐 간 조직내 MT의 분포는 면역조직화학적 방법을 적용하여 광학현미경으로 관찰하였고, 세포내 미세구조적 위치 (localization)는 금 입자 표지를 이용한 면역세포화학적 방법을 이용하여 투과전자현미경으로 관찰하였다. MT는 발생 13일이 경과한 흰쥐 태아의 간에서 처음으로 관찰되기 시작하여, 출생 당일의 신생 흰쥐에서 가장 높게 관찰되었다. 면역 조직화학 및 세포화학적 방법으로 관찰한 결과, MT 염색성은 발생 후기에서 출생후 10일째까지 비교적 높게 나타났다. MT에 대한 양성반응은 난형 세포 (oval cell)들과 간 실질세포 (liver parenchymal cell)들에서 뚜렷하게 존재하였다. 발생과정과 신생 흰쥐의 간 조직에서는 핵과 세포질 양쪽에서 공통적으로 양성 반응을 보였으나, 생후 30일 이후부터 성체에 이르는 시기까지는 세포질에 한정되어 있는 양상을 보였다. 금 입자 표지법에 의한 MT의 세포질내 분포를 보면, 발생 중인 흰쥐 간 세포에서는 핵과 세포질내에 고르게 산재되어 있었다. 즉, 핵내 염색질, 인, 조면소포체 및 cytosol에서도 MT에 대한 면역 금 입자들이 관찰되었으나, 미토콘드리아와 지질 소포 등에서는 거의 관찰되지 않았다. 상기의 결과들은 발생중 혹은 성장중인 흰쥐의 간에서 MT가 점차 증가하는 것으로 요약될 수 있는 것으로서, 이는 MT가 세포들의 증식과 분화에 금속 이온의 저장과 방출 혹은 전사인자 (transcription factor)로서 작용할 수 있음을 암시하는 것으로 판단된다.

Keywords

References

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