抗神經壞死病毒藥物活體篩選平台之建立

Abstract

石斑魚在台灣是一個高經濟價值的養殖魚種，近年來在石斑魚苗時期容易受神經壞死病毒感染，造成大量死亡，死亡率高達95%。有鑑於此，針對病毒防治之藥物開發顯得非常重要。因此，為了建立一個活體的篩藥平台，我們將斑馬魚與青鱂魚這兩種魚種，在不同的階段利用腹腔注射或是浸泡的方式感染病毒。結果顯示，只有青鱂魚成魚在感染後出現病徵且死亡，斑馬魚成魚則沒有。在幼魚浸泡感染的實驗中，青鱂魚幼魚，在孵化後第1、7、14、21、28天，感染病毒後2週的相對存活率為49%、33%、55%、60%、89%。而斑馬魚幼魚在孵化後第1天感染病毒後2週的相對存活率則為92%。由於青鱂魚是種廣鹽性的魚類，所以我們進一步在海水的條件下，將青鱂魚孵化後第一天的幼魚感染病毒，所得到的相對存活率為40%。本實驗結果指出，剛孵化的青鱂魚魚苗，較適合用來建立抗神經壞死病毒藥物的活體篩選平台。

Nervous necrosis virus (NNV), which belongs to the betanodavirus of the Nodaviridae family, is the causative agent of viral nervous necrosis (VNN). It is one of the major viral diseases of hatchery-reared grouper in Taiwan. The infection often causes more than 95% of mortality during larval stage of grouper. Therefore, it is important to develop an anti-NNV drug to prevent virus infection. In order to develop an in vivo screening platform, zebrafish and medaka in different stages are investigated by intra-peritoneal (i.p.) injection or immersion with virus. Results show that the adult medaka but not zebrafish appears erratic swimming and death. In larvae bath infection, the mean relative percent survival (RPS) of medaka infecting NNV at 1, 7, 14, 21, and 28 day-post-hatch (d.p.h.) was 49%, 33%, 55%, 60% and 89%, respectively, after 2 weeks of infection. The mean RPS of zebrafish infecting at 1 d.p.h. was 92% after 2 weeks of infection. Because the medaka is a euryhaline teleost, medaka larvae of 1 d.p.h. infected by NNV in seawater condition show the mean RPS of 40% after 2 weeks of infection. We suggest that 1 d.p.h. medaka larvae are more suitable to establish an in vivo screening platform for an anti-NNV drug.