目的：通过采用局部不同封包时间的 ALA-PDT治疗豚鼠耳背部寻常型银屑病模型, 研究其生物效应并优化治疗参数。方法：豚鼠耳背部涂抹心得安建立寻常型银屑病模型；荧光分光光度计分别检测皮损经 ALA封包 1、3、15h后组织中 PpIX的含量；肉眼观察各组皮损治疗后不同时间段的愈合情况, HE染色观察组织病理学改变, 免疫组化法染色观察表皮细胞增殖(PCNA)及 CD4+和 CD8+T淋巴细胞浸润情况。结果：皮损中 PpIX含量随 ALA封包时间的延长而升高, 15h组＞3h组＞1h组；封包后 PpIX的生成速率 3h组＞1h组＞15h组；皮损痊愈所需时间：15h组＜3h组＜1h组。皮损中的 PCNA、CD4+及 CD8+阳性表达率：15h组＜3h组＜1h组。结论：局部 ALA-PDT治疗豚鼠耳背部寻常型银屑病模型有显著疗效。ALA封包时间的长短与局部皮损中 PpIX生成量成正相关；与皮损痊愈所需的时间成负相关；3h组 PpIX生成速率最快且无副作用, 为最佳封包时间。ALA-PDT可抑制表皮细胞的过度增殖, 减少 CD4+CD8+T淋巴细胞的浸润, 其作用效果与 ALA封包时间成正相关。

Objective: In the paper, we are treating psoriasis vulgaris model of guinea pigs' ear with ALA-PDT of different incubationperiods, thus to investigate its biological effect and to optimize the parameter. Methods: We established psoriasis vulgaris model ofguinea pigs' ear by applying propranolol; fluorospectrophotometer was used to detect the content of PpIX in topical lesions after 1h/3h/15h incubation periods of ALA; we observed lesional recovery time with naked eyes and HE staining at day0,7,14,21,28 after ALA-PDT; immunohistochemical staining was used to observe the changes of PCNA and CD4+, CD8+ T cells in topical lesions. Results: Themean content of PpIX in topical lesions increased with the incubation time and the fastest period is1耀3 h. The lesional recovery time: 15h group＜3h group＜1h group. The mean content of PCNA, CD4+ and CD8+ T cell in topical lesions: 15 h group＜3 h group＜ 1h group. Conclusion: ALA-PDT is effective on psoriasis vulgaris model of guinea pigs' ear. ALA incubation time correlated positively with the content of PpIX in topical lesions, and negatively with the lesional brecovery time. 3h is the best ALA incubationtime in this period. PpIX synthesis is the fastest and has no side effect. ALA -PDT can inhibit the abnormal proliferation of the lesional epidermal cell. It can also reduce the CD4+ and CD8+ T cell level. These effects correlated positively with ALA incubation time.