探討聯苯胺對斑馬魚產生凋亡與血管新生作用

聯苯胺(Benzidine)是一種人工製造的化學製品，它主要被用來使用於染料的加工與製造上，尤其是在一些皮革工廠、紡織廠以及造紙廠中。在先前的研究證明了，在長期暴露在聯苯胺的環境之下確實會增加人類罹患膀胱癌的風險，然而，聯苯胺暴露在外的環境毒性是如何影響胚胎發育仍然未被說明清楚。本研究利用了斑馬魚做為動物實驗模式，並研究是否在聯苯胺環境暴露之下對於斑馬魚會造成毒性危害。在本實驗結果中發現，暴露在聯苯胺環境中斑馬魚的死亡率會隨著聯苯胺暴露的濃度與時間增加而增加，此外暴露聯苯胺之下會造成斑馬魚胚胎頭部以及背部產生明顯的凋亡現象，並且造成斑馬魚胚胎會產生頭部發育畸形與不正常現象。在半定量PCR結果中發現聯苯胺會活化p53表現並其活化下游bax與noxa表現。而在透過原位雜合實驗發現聯苯胺會造成斑馬魚的Otx2訊號變弱。接著利用轉殖基因斑馬魚(fli1:EGFP)發現在高濃度聯苯胺(100 μM與200 μM)暴露之下會造成斑馬魚血管生成的不正常現象。總括實驗結果發現聯苯胺會對斑馬魚造成神經系統傷害、血管生成不正常以及明顯的凋亡現象，而這些不正常的發育現象最後將會導致斑馬魚走向死亡。

Benzidine, a manufactured chemical that does not occur naturally, is used as manufacture dyes, especially azo dyes in the leather, textile, and paper industries. Previous studies have demonstrated that persistent exposure to benzidine increased the accidence of bladder cancer, however, the environmental toxicity of benzidine still remained to be elucidated. Here, we used zebrafish as a model to investigate the toxicity and teratogenicity of benzidine. Exposed to benzidine induced mortality in a dose- and time-dependent manner. Furthermore, treated with benzidine resulted in massive apoptosis, particularly in the brain and dorsal axis region. Malformation of the brain region and disruption of forebrain/midbrain and midbrain/hindbrain boundary was also found in benzidine-treated embryos. RT-PCR analysis revealed that Benzidine activates p53-dependent pathway and increase bax and noxa activites. In addition, benzidine attenuated Otx2 gene expression as evidenced by whole mount in situ hybridization. More strikingly, exposed to high dose of benzidine (100 μM and 200 μM) exhibited abnormal blood vasculogensis in transgenic fli1:EGFP zebrafish. Taken together, our data suggest benzidine-induced neurotoxicity and abnormal vasculogensis which resulted in markedly abnormal development and eventually caused death of zebrafish。