腸道病毒A71型(EV-A71)是與神經發病機制相關的嚴重手足口病 (HFMD) 的主要病原體之一。根據報導在過去20年中，亞太國家爆發了EV-A71病毒並導致數千名兒童死亡。然而，目前還沒有有效的藥物或疫苗來預防EV-A71感染。因此，建立EV-A71感染的動物模型以及開發治療EV-A71感染的新藥物迫在眉睫。hSCARB2基因轉殖鼠已經被發表，並充當EV-A71研究的動物實驗。我們之前的研究顯示，人類核仁蛋白（hNCL）在體內外都能促進EV-A71的結合和感染。在這裡，我們試圖建立hNCL/hSCARB2基因轉殖鼠來研究EV-A71的發病機制。7天年齡的小鼠經由腹腔注射來感染病毒，觀察小鼠臨床評分/存活率且同時對小鼠進行基因型鑑定。此外，我們還評估了體重變化和小鼠犧牲後去測量不同組織的病毒載量。我們發現hSCARB2和hNCL/hSCARB2基因轉殖鼠比野生型小鼠（WT）和hNCL基因轉殖鼠表現出更高的死亡率和體重減輕更多。在外觀上則是觀察到皮膚脫落及相似手足口病的指尖出血性病變。進一步，在全部種類基因轉殖鼠肌肉的病毒載量均高於腦幹和脊髓，我們還發現hNCL/hSCARB2基因轉殖鼠的肌肉組織比野生型小鼠破壞的更嚴重，且在腦幹、脊髓和肌肉中有較高的EV-A71-VP1訊號。此外，我們還評估了hNCL/hSCARB2 基因轉殖鼠是否有肺水腫。雖然我們發現野生型小鼠和基因轉殖鼠的肺/體重比沒有差異，但在hNCL/hSCARB2基因轉殖鼠的肺組織中觀察到的出血和腫脹比野生型小鼠更多。在顯微鏡下觀察到hNCL/hSCARB2基因轉殖鼠的肺切片中紅血球的浸潤。這個結果可能揭示一些關於肺水腫的信息。根據我們的研究結果，表達hNCL/hSCARB2基因轉殖鼠是研究EV-A71發病機制的最佳動物模型之一。EV-A71的發病機制，尤其是在它們導致嚴重的神經發病機制的情況下，仍然知之甚少。當前研究中開發的動物模型可能有助於促進 EV-A71 的藥物發展和疫苗研究。

Enterovirus A71 (EV-A71) is one of the major causative agents of the severe forms of hand, foot and mouth disease (HFMD) associated with neuropathogenesis. EV-A71 outbreaks have been reported in Asia-Pacific countries, resulting in thousands of children deaths during the past 20 years. However, there are no effective drugs or vaccine to prevent EV-A71 infection. Therefore, to establish an animal model for the development of new treatment or drug for EV-A71 infection is in urgent. Human scavenger receptor class B member 2 (hSCARB2) transgenic (Tg) mice have been established and used as EV-A71 animal studies. Our previous studies also indicated that human nucleolin (hNCL) could facilitate EV-A71 binding and infection in vitro and in vivo. Here we are trying to develop hNCL/hSCARB2 double Tg mice to investigate EV-A71 pathogenesis. 7-day-old mice was infected with viruses intraperitoneally and the clinical score/survival rate of the mice were obtained. Genotyping of the mice was performed at the same time. In addition, we also evaluated the weight change, and the viral load of different tissues after sacrifice. We found that hSCARB2 and hNCL/hSCARB2-Tg mice showed higher mortality and more weight loss than wild-type mice and hNCL-Tg mice. Hemorrhagic lesions in the fingertip similar to that of HFMD and desquamation on skin were observed. Further, muscles exhibited the highest viral load than brain stem and spinal cord in all kinds of transgenic mice. We also found that hNCL/hSCARB2-Tg mice showed more severely destroyed in muscle and had higher EV-A71-VP1 signals in brain stem, spinal cord, and muscle by IHC staining than in the C57BL/6 wild-type (WT) mice. Furthermore, we also evaluated whether hNCL/hSCARB2-Tg had pulmonary edema (PE). Although we found no difference in the lung/body weight ratio between WT and Tg mice, more hemorrhages and swollen were observed in lung tissue of hNCL/hSCARB2-Tg mice than in the WT mice. We also observed infiltration of erythrocytes in the lung section of hNCL/hSCARB2-Tg mice under the microscope. This result may reveal some information about PE. Based on our findings, it is suggested that hNCL/hSCARB2-Tg mice is one of the best animal models for studying the pathogenesis of EV-A71. The pathogenesis of EV-A71, especially in cases where they cause severe neuropathogenesis, remains poorly understood. The animal model developed in current study may show light on drug discovery and vaccine investigation for EV-A71.

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