| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 94 === Abstract
Catechins are polyphenol compounds extracted from green tea. They are reported to have a variety of medicinal effects such as anti-tumor, anti-oxidation, anti-inflammation and anti-virus. Japanese encephalitis virus (JEV), a neurotropic flavivirus, is one of the major causes of acute encephalitis in human. Upon infected, it is commonly associated whit inflammatory reactions and neurological diseases. To date, there are no any effective medicines for Japanese encephalitis therapy. This study aims to investigate the physiological effects of catechins administration when infected by Japanese encephalitis virus (JEV). In vitro experiments indicated that catechins have cytotoxicity to Vero cells at high concentration (125μg/ml). However, catechins can significantly inhibit the replication of JEV in both Vero and nixed glia cells. Catechins not only inhibit NO production in nixed glia cells when induced by LPS, but also reduce iNOS mRNA transcription when infected by JEV in nixed glia cells. JEV infects C3H/HeN mice that demonstrates neurobehavioral abnormalities at the 5th day of post-infection and dies at the 7th day of post-infection. At the 5th day of post-infection, the expression of JEV envelope protein in brain regions can be detected by dot blotting and real-time PCR. JEV mainly replicates in the cerebrum in mice. We found out that catechins can only slightly inhibit viral replication, and the virus can also induce inflammation in the brain of mice. The high expression levels of iNOS and the productions of inflammation-associate cytokines in the brain of JEV infected mice can be detected by the real-time PCR and dot blot assay. The expression levels of iNOS、IL-6、TNF-α and RANTES in different brain regions of mice when fed with catechins is slightly inhibited, but IL-1β and IFN-γ are not.
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