纖維蛋白溶解系統的胞漿素(plasmin)具有造成細胞間質裂解而使組織受破壞的特性，而纖維蛋白溶解系統由胞漿素原(plasminogen)與plasmin所組成；由於先前研究曾指出根尖囊腫具有纖維蛋白溶解活性，因此進一步的探討根尖囊腫中的胞漿素原活化劑(plasminogen activator)與胞漿素原活化抑制劑(plasminogen activator inhibitor)的表現，將有助於對根尖囊腫病理過程的了解。本實驗的目的在於探索組織型胞漿素活化劑(tissue type plasminogen activator；簡稱tPA)與第一型胞漿素原活化抑制劑(type plasminogen activator inhibitor；簡稱PAI-1)，在根尖囊腫中表達的位置。本實驗取30個根尖囊腫病例，施以蘇木精與伊紅染色(hematoxylin and eosin)和免疫組織化學染色；每一個根尖囊腫標本皆製作一片蘇木精與伊紅染色切片，作為判定根尖囊腫的發炎程度依據；分析根尖囊腫中tPA或PAI-1的表現程度與發炎程度的關聯性，並以Fisher’s exact test來檢定其是否具有統計學上的意義。實驗結果顯示在囊腫內襯上皮、結締組織、發炎細胞浸潤處和血管可發現具有tPA或PAI-1表達的細胞，tPA主要表現在上皮細胞及發炎細胞，而PAI-1則主要表達在纖維母細胞、血管內皮細胞，進一步以統計方法檢定後發現，tPA的表現程度會隨根尖囊腫發炎程度的變化而變化 (P<0.05)；此外PAI-1表現程度也會隨根尖囊腫發炎程度的變化而變化 (P<0.05)。本研究證實根尖囊腫中同時具有胞漿素活化劑與胞漿素活化劑抑制劑的存在，且進一步指出tPA與PAI-1表現在根尖囊腫的上皮、發炎細胞、纖維母細胞、血管內皮細胞，另外根尖囊腫發炎程度也與tPA及PAI-1表達程度有相關。
The plasminogen/plasmin proteolytic system participates in a wide variety of extracellular matrix degradation. Detailed knowledge of plasminogen activator and its inhibitor may be important for understand the pathogenesis of radicular cysts. The purpose of this study was to investigate the in situ localization of tissue type plasminogen activator (tPA) and type plasminogen activator inhibitor (PAI-1) in radicular cysts. Thirty formalin-fixed, paraffin-embedded specimens of radicular cysts were examined using immunohistochemistry. A perioxidase-labeled streptavidin-biotin technique was used for identification of the tPA and PAI-1. One section from each radicular cyst specimen was stained with hematoxylin and eosin to access the presence of the inflammatory infiltrates. Differences in tPA or PAI-1 expression between tissue with low and high levels of inflammation were subsequently analyzed using Fisher’s exact test. Both tPA and PAI-1 positively stained cells were detected in the lining epithelium, connective tissue, inflammatory infiltrates, and endothelium. In addition, the tPA signal was mainly expressed in epithelial cells, infiltrating cells . However, the PAI-1 signal was mainly expressed in fibroblasts. Moreover, significantly greater tPA as well as PAI-1 expression was noted in radicular cysts with high levels of inflammation as compared to tissues with low levels of inflammatory cell infiltrates (P<0.05). The present study confirms earlier indications of local production of plasminogen activator and its inhibitor in radicular cysts. In addition, this study further shows that the tissue localization of the antigen for tPA or PAI-1 and demonstrates that the experession of both tPA and PAI-1 increases with the grade of inflammation in radicular cysts.
