Abstract
This study was carried out to investigate cytotoxicity of paraquat or bentazone on NIH 3T3 fibroblasts, toxicity of paraquat or bentazone, and compensatory effects of 3-Methylcholanthrene(3-MC) on the rat liver. In order to MTT assay, the $5.0{\times}10^4$ cell/mL of NIH 3T3 fibroblast in each well of 24 multidish were cultured. After 24 hours, the cells were treated with solution of paraquat or bentazone(1, 25, 50, 100 ${\mu}M$ respectively). After the NIH 3T3 fibroblast of all groups were cultured in same condition for 48 hours. MTT assay were performed to evaluate the cytotoxicity of cell organelles. Paraquat or bentazone $MTT_{50}$ were 1668.97 ${\mu}M$ and 1506.97 ${\mu}M$, respectively. These $IC_{50}$ of paraquat or bentazone were decided low cytotoxicity by Borenfreund. In order to observe the toxicity and compensatory effects of paraquat or bentazone on the rat liver, Sprague-Dawley male rats were used as experimental animals and divided into paraquat or bentazone only treated group and simultaneous application group of paraquat or bentazone and 3-MC. At 30 min and 1, 3, 6, 12, 24, 48 and 96 hrs interval after each treatment, the animals were sacrificed by decapitation and liver were immediately removed, immersed in fixatives, and processed with routine method for light microscopic study. Paraffin sections were stained with H-E, PAM and Best Carmine. Under the light microscope, degenerative changes of hepatic lobules were frequently observed in portal area from 3 hrs after paraquat or bentazone treatment. All hepatic cells were induced degenerative change at 12 hrs and more severe degenerative change at 48 hrs after paraquat or bentazone treatment. Especially, hepatic cells of bentazone only treated group were distinctly showed pyknotic. Glycogen granules were increased in portal area at 3 hrs, all hepatic cells at 12 hrs and remarkably increased at 48 hrs after paraquat or bentazone treated group. But hepatic cells of bentazone only treated group were regeneration at 48 hrs from portal area and glycogen granules of hepatic cells of paraquat or bentazone and 3-MC combination treated group showed in central area only at 48 hrs. The results indicate that 3-MC may be decrease paraquat or bentazone cytotoxicity on the rat liver.
Paraquat와 bentazone이 횐쥐의 간조직과 NIH 3T3 섬유모세포에 미치는 독성과 그 독성에 대한 3-MC의 보상효과를 조사하기 위하여 NIH 373 섬유모세포에 적응한 후 경시적으로 MTT분석을 이용하여 세포독성을 측정하고 Sprague Dawley계 웅성 횐쥐에 paraquat와 bentazone단독 및 paraquat 및 bentazone과 3-MC를 병용투여한 후 경시적으로 관찰한 결과 paraquat와 bentazone은 NIH 3T3 섬유모세포에 대하여 $IC_{50}$값이 각각 1668.97 ${\mu}M$, 1506.97 ${\mu}M$으로 Borenfreund의 독성평가기준에 의하면 저독성이었다. Paraquat와 bentazone 단독투여군의 H&E 염색에서 3시간째에는 문맥 주위 세포들이 변성을 일으키고 별모양 세포들이 증가하였으나 12시간째에는 간소엽 전체의 세포들이 변성을 일으켰으며 48시간째에는 더욱 심한 변성이 일어났다. 특히 bentazone 투여 후 48시간째에는 핵농축현상이 뚜렷하였다. Best carmine 염색에서 glycogen 과립을 함유하는 간세포들도 3시간째에는 문맥주위의 세포들이, 12시간째에는 간소엽 전체의 간세포들이, 48시간째에는 전체의 간세포들이 함유하는 glycogen 과립량이 현저히 증가하였다. 3-MC를 paraquat와 bentazone과 동시에 투여한 군에서 3시간째와 12시간째에는 단독투여군과 유사하였으나 48시간째에는 bentazone과 3-MC 동시투여군의 문맥주위의 간세포들이 재생되는 경향이었으며 paraquat와 3-MC를 동시에 투여한 군에서는 중심정맥 주위의 세포들만이 glycogen과립을 함유하고 있어 단독 투여군과 뚜렷한 차이를 관찰할 수 있었다. 이 결론에서 3-MC는 paraquat와 bentazone에 의한 간세포의 독성을 경감시킬 수 있는 물질임을 알 수 있었다.
(Division of Environment and Agricultural Science, College of Agriculture and Life Sciences, Sunchon National University)
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