Chang Yi-Sheng, Chen Wen-Chung, Tseng Sung-Huei, Sze Chun-I, Wu Chao-Liang
Department of Ophthalmology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Cornea. 2008 May;27(4):471-5. doi: 10.1097/ICO.0b013e318164221c.
Subconjunctival injection of mitomycin C (MMC) before pterygium excision is a new adjunctive therapy to decrease pterygium recurrence. This study aimed to investigate the ultrastructural changes in pterygium after subconjunctival injection of MMC.
Four patients underwent subconjunctival injection of 0.1 mL of 0.15 mg/mL MMC 1 month before pterygium excision, and 2 patients served as controls without preoperative MMC injection. The excised specimens of pterygium were examined under transmission electron microscopy.
Epithelial cells of the treated pterygium remained unchanged. However, stromal fibroblasts were decreased in number, were oval rather than spindle-shaped, and had shrunken cytoplasmic processes; some were degenerating or apoptotic. Collagen and elastic fibers were decreased in density, disorganized, and degenerated. Capillary endothelial cells were thickened and swollen, with narrow or obliterated lumens. Axonal swelling and demyelination were observed.
Subconjunctival injection of MMC inhibits fibrovascular activity in the pterygial stroma, leading to degeneration of the extracellular matrix and nerve axons. These ultrastructural changes are consistent with the clinical observation of reduced vascularity in the pterygium after MMC injection and verify the effectiveness of subconjunctival MMC injection 1 month before pterygium excision in decreasing the risk of pterygium recurrence.
在翼状胬肉切除术前结膜下注射丝裂霉素C（MMC）是一种降低翼状胬肉复发率的新型辅助治疗方法。本研究旨在探讨结膜下注射MMC后翼状胬肉的超微结构变化。
4例患者在翼状胬肉切除术前1个月结膜下注射0.1 mL 0.15 mg/mL的MMC，2例患者作为对照，术前未注射MMC。对切除的翼状胬肉标本进行透射电子显微镜检查。
接受治疗的翼状胬肉上皮细胞无变化。然而，基质成纤维细胞数量减少，呈椭圆形而非梭形，胞质突起缩短；部分细胞正在退变或凋亡。胶原纤维和弹性纤维密度降低、排列紊乱且发生退变。毛细血管内皮细胞增厚、肿胀，管腔变窄或闭塞。观察到轴突肿胀和脱髓鞘现象。
结膜下注射MMC可抑制翼状胬肉基质中的纤维血管活性，导致细胞外基质和神经轴突退变。这些超微结构变化与MMC注射后翼状胬肉血管减少的临床观察结果一致，并证实了翼状胬肉切除术前1个月结膜下注射MMC在降低翼状胬肉复发风险方面的有效性。
