Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.
Department of Ophthalmology, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin, Korea.
Invest Ophthalmol Vis Sci. 2021 Apr 1;62(4):14. doi: 10.1167/iovs.62.4.14.
Comparison of the parasympathetic and sympathetic neurons, including the dopaminergic neural system, in dry eye (DE)-induced pathophysiology has not been elucidated well. This study investigated the presence of dopamine receptors (DRs) and their functional roles in the lacrimal glands (LGs) of DE-induced mice.
After DE was induced in B6 mice for 2 weeks, the expression of tyrosine hydroxylase (TH), dopamine, and DRs (DR1, DR2, etc.) in the LGs and corneas were measured by quantitative RT-PCR, immunoblot, and ELISA. Using flow cytometry and ELISA, immune cell infiltration and inflammatory cytokine expression were determined in DE-induced LGs with or without DR blockers, SCH-23390 (DR1i), or melperone (DR2i). Corneal erosion scores were also investigated.
The mRNA and protein levels of TH significantly increased in DE-induced LGs. The dopamine concentration of LGs was 9.51 pmol in DE (versus naive: 1.39 pmol; P < 0.001). Both DR1 and DR2 mRNA expression were significantly enhanced in desiccating stress compared with those in naive (3.7- and 2.1-fold, P < 0.001). Interestingly, DR1 and DR2 immunostaining patterns stained independently in DE-induced LGs. CD3+ and CD19+ cell infiltration was significantly increased by DR2i (P < 0.001) but not by DR1i. Furthermore, IFN-γ, IL-17, and TNF-α were significantly upregulated by DR2i compared with the blow-only condition. The severity of corneal erosion and inflammation was also aggravated by DR2i.
Upregulation of DR1 and DR2 was observed in DE-induced mouse LGs. As the inflammatory conditions are aggravated by the inhibition of DRs, especially DR2, their activity may be an important factor preserving ocular surface homeostasis.
干眼症（DE）诱导的病理生理学中，副交感和交感神经元，包括多巴胺能神经系统的比较尚未得到很好的阐明。本研究旨在研究多巴胺受体（DR）在 DE 诱导的小鼠泪腺（LG）中的存在及其功能作用。
在 B6 小鼠中诱导 DE 2 周后，通过定量 RT-PCR、免疫印迹和 ELISA 测量 LG 和角膜中酪氨酸羟化酶（TH）、多巴胺和 DR（DR1、DR2 等）的表达。使用流式细胞术和 ELISA，在存在或不存在 DR 阻滞剂 SCH-23390（DR1i）或美普龙（DR2i）的情况下，确定 DE 诱导的 LG 中的免疫细胞浸润和炎症细胞因子表达。还研究了角膜侵蚀评分。
TH 的 mRNA 和蛋白水平在 DE 诱导的 LG 中显着增加。LG 中的多巴胺浓度在 DE 中为 9.51 pmol（与对照相比：1.39 pmol；P <0.001）。与对照相比，干燥应激下 DR1 和 DR2 的 mRNA 表达均显着增强（3.7-和 2.1 倍，P <0.001）。有趣的是，DR1 和 DR2 免疫染色模式在 DE 诱导的 LG 中独立染色。DR2i 显着增加 CD3+和 CD19+细胞浸润（P <0.001），但 DR1i 没有。此外，与仅吹风条件相比，DR2i 显著上调 IFN-γ、IL-17 和 TNF-α。DR2i 还加重了角膜侵蚀和炎症的严重程度。
在 DE 诱导的小鼠 LG 中观察到 DR1 和 DR2 的上调。由于抑制 DR，特别是 DR2，会加剧炎症状态，因此它们的活性可能是维持眼表稳态的重要因素。
