冬蟲夏草菌絲體對A群鏈球菌感染的保護效果之研究

莊偉哲
國立成功大學
A群鏈球菌的感染會造成多種病症，包括輕微的咽喉炎、膿皰病、猩紅熱，到致命的壞死性筋膜炎及毒性休克症候群，也可能造成非化膿性後遺症，如急性腎絲球腎炎和風濕性心臟病。儘管現今有一些有效的抗生素，但近年來，由A群鏈球菌感染造成嚴重疾病在全世界都有增加的趨勢。在台灣各個年齡層的病人都可能引起壞死性筋膜炎、毒性休克症候群、及非化膿性後遺症，而且目前仍無疫苗可用。先前在小鼠的研究顯示，冬蟲夏草菌絲體對A群鏈球菌的感染提供保護效果。我們並且發現冬蟲夏草菌絲體會誘發細胞激素的產生，而使得A群鏈球菌產生的毒素streptococcal pyrogenic exotoxin B (SPE B)所造成的吞噬作用的抑制有回升的現象。為了進一步分析冬蟲夏草菌絲體在細菌感染的功效，利用先前建立的A群鏈球菌從氣囊感染小鼠的模式，並且以餵食方式給予冬蟲夏草菌絲體萃取物。本計畫第一項特定目標採用large-scale screening，以cDNA microarray大量篩選比較未給予和給予冬蟲夏草菌絲體萃取物在A群鏈球菌感染小鼠的脾臟細胞，與發炎反應、免疫反應及訊息傳遞相關基因表現的變化，並以RT-PCR、Western blot或ELISA來證實。對於chemokines 和cytokines的產生則以protein array做進一步的大量檢測。計畫第二項特定目標擬將冬蟲夏草菌絲體萃取物分成不同fractions，以A群鏈球菌感染小鼠模式探討不同fractions可能提供的保護效果，比較小鼠存活率，並偵測局部組織和器官傷害程度、細菌生長與散佈、免疫細胞浸潤、以及chemokines和cytokines的產生。依據第二項特定目標所得的結果，計畫第三項特定目標將以具有活性的fractions給予小鼠，取脾臟細胞再一次進行screening，與第一項特定目標所得的結果做比較。基於前三項目標所得之結果，計畫第四項特定目標將針對冬蟲夏草菌絲體萃取物誘發產生的特定因子以blocking antibodies或siRNA或外加的方式，去確認這些因子在A群鏈球菌感染可能提供的保護作用機制。綜而言之，本計畫以小鼠感染A群鏈球菌模式，針對冬蟲夏草菌絲體之保護功效進行研究，期能建立一中醫藥及健康食品篩選平台，並進一步在不同病菌感染之運用。
關鍵字：冬蟲夏草菌絲體；A群鏈球菌；感染小鼠模式

Protective effect of Cordyceps sinensis mycelium in group A streptococcal infection

Woei-Jer Chuang
National Cheng Kung University
Group A streptococcus (GAS) causes a wide spectrum of diseases, ranging from mild pharyngitis, impetigo, and scarlet fever to life-threatening diseases including necrotizing fasciitis and streptococcal toxic shock syndrome. Nonsuppurative sequelae, such as acute glomerulonephritis and rheumatic heart disease, may also occur. Despite the availability of effective antimicrobial agents, there has been a worldwide increase in the incidence of serious invasive GAS infection in recent years. In Taiwan, patients of all ages with necrotizing fasciitis, toxic shock syndrome, and post-infection sequelae have been reported. No vaccine is available. Our previous studies have shown that Cordyceps sinensis mycelium protected mice from GAS infection. We also demonstrated that C. sinensis mycelium abrogated the streptococcal pyrogenic exotoxin B (SPE B)-mediated suppression of phagocytosis in monocytic cells by inducing the production of cytokines. To further characterize the effects of C. sinensis mycelium in microbial infections, mice are inoculated with GAS via an air pouch with or without force-feeding with C. sinensis mycelium. Specific Aim 1 of this project is using a large-scale screening by cDNA microarray to examine the inflammation-, immune response-, and signal transduction-related gene expression in mouse spleen cells after GAS infection with or without C. sinensis mycelium treatment. Gene expression will be further confirmed using RT-PCR, Western blot, or ELISA.
關鍵字：Cordyceps sinensis mycelium；group A streptococcus；infection mouse model