戴奧辛抑制脂多醣體所誘導人類 Astrocytoma U373 MG 細胞株之介
白質素-6 的釋放
Secretion of Lipopolysaccharide Induced Interleukin-6 Expression by 2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin on Human Astrocytoma U373 MG Cells
中文摘要 論文摘要
戴奧辛抑制脂多醣體所誘導人類 Astrocytoma U373 MG 細胞株之介白質素-6 的釋放
張慧文 指導教授:楊沂淵 博士
環境污染對免疫系統的影響已被廣泛的研究且一直是引起爭論的話題，因此許多 科學家對戴奧辛 (dioxin) 的研究深感興趣。戴奧辛的產生主要來自物質製造過程 中使用含氯的石碳酸﹐或將含氯的化學物燃燒所產生。戴奧辛被懷疑對中樞神經 發育會有不好的影響。而神經膠細胞在中樞神經的重要性是參與神經細胞損傷及 修復。許多的研究證實，發炎反應通常參與許多神經性退化性疾病的病理過程。
愛滋病、痴呆、阿滋海默症等神經病變疾病會使得腦脊髓液和腦中 IL-6
(interleukin-6) 量增加。在本篇研究中，我們探討 TCDD (2,3.7.8-Tetrachlorodibenzo -p-dioxin) 對人類神經膠細胞 (U373 MG cells) 產生 IL-6 細胞激素的影響。首先，
以酵素免疫 (ELISA) 方法測量分析 TCDD 對人類 Astrocytoma U373 MG 細胞 IL-6 的釋放並不影響，但會抑制 LPS (Lipopolysaccharide) 所誘導 U373 MG 細胞 IL-6 之釋放。因此，利用分析 MTT、LDH 試驗顯示，TCDD 的作用並不會減少 U373 MG 細胞生存率。再者，藉由細胞化學免疫染色法及西方墨點法發現 TCDD 對 U373 MG 細胞中的 ARNT (aryl hydrocarbon receptor nuclear translocator) 並無顯著的影 響。此外，藉由 RT-PCR 進一步探討 TCDD 作用於老鼠大腦皮質之 AhR、ARNT、
IL-1β 和 IL-6 mRNA 表現的影響。實驗結果顯示 TCDD 會抑制 AhR、IL-1β 和 IL-6 mRNA 的表現。但 TCDD 在老鼠腦脊髓液中會誘導 IL-6 的表現。這些結果 顯示 TCDD 曝露在不同的組織會造成不同的結果。無疑地，TCDD 對體內的影響 是多變且複雜，或許牽涉到許多細胞類型和細胞激素間的相互作用。
英文摘要
Suppression of Lipopolysaccharide Induced Interleukin-6 Secretion by
2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin on Human Astrocytoma U373 MG Cells Hui-Wen Chang
Thesis advised by: Yi-Yuan Yang, Ph.D.
The effect of environmental pollutants on the immune system has been a well-studied
and controversial topic, with dioxins heading the list of molecules under investigation.
Mainly produced as a by-product of the manufacture of materials requiring the use of chlorinated phenol, or as a result of the incineration of chlorinated chemical products.
Dioxin is suspected to cause adverse effects on the development of the central nervous system (CNS). Astrocytes are now believed to play important roles in
repairing injured neurons. It is now recognized that inflammation is centrally involved in the pathogenesis of a number of neurodegenerative diseases. AIDS, dementia, and Alzheimer’s disease lead to an increase in the level of IL-6 (interleukine-6) in the CSF and brain. In this study, we investigated the effects of TCDD
(2,3.7.8-Tetrachlorodibenzo-p-dioxin) on IL-6 expression in U373 MG cells. Data indicated that TCDD doesn’t effect of IL-6 secretion on human Astrocytoma U373 MG cells, but suppress of LPS (lipopolysaccharide) -induced IL-6 secretion as measured by enzyme-linked immunosorbent assay (ELISA). The treat effects of TCDD were not due to decreased U373 MG cells viability as assessed by MTT、LDH test. No effect of ARNT expression was estimated through immunocytochemistry and western blot in U373 MG Cells by TCDD. Furthermore, TCDD inhibit AhR, IL-1β and IL-6 mRNA expression on rat cortical neuron as detected by RT-PCR. But TCDD uptake resulted in a significant increase in IL-6 level in the mouse CSF. These results suggest that in vivo exposure to TCDD may differ between tissues. Clearly, the effects of TCDD in vivo are varied and complex, likely involving interactions between many cell types and cytokine feedback loops.
