局部α2-肾上腺素受体激动剂在睑板腺功能障碍中的作用及其机制研究

Meibum produced by the meibomian glands is essential for the maintenance of ocular surface health and stability. Meibomian gland dysfunction (MGD), characterized by terminal duct obstruction and/or qualitative/quantitative changes in the meibum, may result in dry eye and ocular surface disease. Conventional therapeutic measures of MGD are often unsatisfactory or not well tolerated. In our previous studies, we have successfully cultured immortalized human meibomian gland epithelial cells (iHMGECs), and used the proliferation and differentiation conditions to imitate the environment in vivo; we also found that α2-adrenergic receptor agonists (α2-ARA, a class of anti-glaucoma medications) can promote a dose-dependent differentiation of iHMGECs and have no effect on the morphology and proliferation of iHMGECs under tissue concentration. Moreover, we have demonstrated that both α2-ARA and azithromycin positively influence the differentiation of iHMGECs, whereas the latter has been used to treat MGD in clinic. We thus hypothesize that α2-ARA may be beneficial for MGD. In this study, we intend to further elucidate the mechanisms of α2-ARA induced differentiation by primary culture of HMGECs. We plan to use an in vivo MGD model to investigate the impact of α2-ARA at the molecular, cellular and overall levels. We design to evaluate the changes in meibomian glands and dry eye in patients with primary open angle glaucoma/ocular hypertension accompanied by MGD who only receive topical α2-ARA. The ultimate goal of this study is to provide new ideas for MGD treatment.

睑板腺合成和分泌的睑酯是维持眼表健康和稳定的关键，其异常(即睑板腺功能障碍，MGD)将导致干眼和眼表疾病。MGD常规治疗效果欠佳或耐受性不好。在前期实验中，我们成功培养了永生的人睑板腺上皮细胞（iHMGECs），且利用不同培养条件模拟体内睑板腺上皮细胞增殖和分化的生理状态，并发现抗青光眼药物α2-肾上腺素受体激动剂(α2-ARA)剂量依赖的促进iHMGECs合成脂质并分化、且在组织浓度下不影响iHMGECs形态和增殖。我们已证实α2-ARA和阿奇霉素均能促进iHMGECs合成脂质并分化，而后者已用于MGD治疗。据此我们推测α2-ARA可能有助于改善MGD。本项目拟培养原代HMGECs，阐明α2-ARA促进HMGECs分化的作用机制；建立MGD动物模型，从分子、细胞及整体水平研究α2-ARA对MGD的影响；临床评估伴有MGD、使用单一α2-ARA患者睑板腺及干眼变化；为MGD治疗提供新思路。

睑板腺合成和分泌的睑酯是维持眼表健康和稳定的关键，其异常(即睑板腺功能障碍，MGD )将导致干眼和眼表疾病。MGD常规治疗效果欠佳或耐受性不好。我们的前期研究结果表明，抗青光眼药α2-肾上腺素受体激动剂（溴莫尼定）剂量依赖性促进永生化的人睑板腺上皮细胞系（iHMGECs）的分化增加，并且伴随着磷脂的累积和p38 MAPK信号通路的抑制。本项目在前期工作的基础上，探究了溴莫尼定促进睑板腺上皮细胞分化的机制。通过透射电镜、荧光染色等方法，我们证明了溴莫尼定能通过引发药物诱导的磷脂病（Drug-induced phospholipidosis, DIPL）促进睑板腺上皮分化，并且该作用可能与溶酶体自噬有关。同时，我们发现炎症因子IL-1β抑制大鼠睑板腺上皮细胞的增殖和分化，并诱导上皮细胞过度角化。抑制p38 MAPK信号通路虽然也抑制细胞增殖，但可阻断炎症因子IL-1β导的大鼠睑板腺上皮细胞分化减少及过度角化，这为临床治疗MGD提供了新思路。

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