星狀膠質細胞是中樞神經系統中，數量最多的膠質細胞，和微血管形成血腦屏障，避免微生物和有毒物質入侵到中樞神經系統，傷害神經細胞。星狀膠質細胞另一個重要的功能為提供神經細胞能量，並調節離子的濃度，穩定中樞神經系統的環境。中樞神經系統受傷後，星狀膠質細胞參與膠質疤的形成，其細胞骨架蛋白GFAP和vimentin大量增加，排列成緊密的結構，形成一種物理性的屏障，阻礙神經細胞的再生。中樞神經系統受傷後，小膠質細胞（中樞神經系統的巨噬細胞）負責釋放前發炎因子、過氧化物和一氧化氮等，引起發炎反應，一般認為前發炎因子會刺激GFAP和vimentin的增加，而IL-18是一種前發炎因子，又稱為干擾素誘導因子，在中樞神經系統中主要由小膠質細胞所釋放，其對於星狀膠質細胞的作用仍不清楚。本實驗發現IL-18能增加初級星狀膠質細胞GFAP和vimentin的表現。將IL-18處理小膠質細胞株BV2 cells的條件培養基，培養初級星狀膠質細胞，也能造成GFAP和vimentin的增加。IL-18注射到雄性大白鼠成鼠的corpus callosum，三天後在注射區域表現GFAP和vimentin的細胞有增加的情形，且細胞有肥大、聚集的現象，此為膠質疤的特徵，顯示IL-18可能藉由增加GFAP和vimentin的表現，而參與膠質疤的形成。

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