Department of Ophthalmology, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, P.R.China.
Curr Eye Res. 2022 Jan;47(1):32-40. doi: 10.1080/02713683.2021.1952603. Epub 2021 Jul 18.
To compare the expression levels of miR-15a between pterygium and normal conjunctiva, and further investigate the potential role of miR-15a in the progression of pterygium.
21 cases of primary pterygium were enrolled in our study. The length of the pterygium invaded into the cornea and the total thickness of the pterygium were measured with anterior segment optical coherence tomography (AS-OCT). The pterygial and adjacent normal conjunctival samples of the 21 patients were collected. Expressions of miR-15a, BCL-2, Bax in both pterygium and normal conjunctiva were measured, and correlations between miR-15a and BCL-2, miR-15a and Bax, miR-15a and clinical parameters were made. Pterygium epithelial cells (PECs) were isolated, cultured and transfected with miR-15a mimic or miR-15a inhibitor to interfere the miR-15a expression levels. The regulation of BCL-2 expression by miR-15a was examined with Real-Time PCR (RT-PCR), Western blot and immunofluorescence. The regulation of Bax expression by miR-15a was also examined with Real-Time PCR (RT-PCR) and Western blot. The cell viability of the transfected PECs was measured with the CCK-8 assay and the apoptosis in these cells was detected using the TUNEL assay.
The expression of miR-15a, Bax were significantly decreased while the BCL-2 was significantly increased in pterygium ( < .05). There was a negative correlation in expression between miR-15a and BCL-2 in pterygium tissues (r = -0.516, < .05). We also found that relative miR-15a level was positively correlated with the length of pterygium invaded into the cornea (r = -0.570, < .05). In cultured PECs, miR-15a could downregulate the expression of BCL-2 and upregulate the expression of Bax. Promotion of miR-15a could suppress cell proliferation and promote cell apoptosis in cultured PECs.
Our study demonstrated that decreased expression of miR-15a in pterygium might be associated with the apoptosis and proliferation of abnormal cell via regulating BCL-2, which could subsequently contribute to the development of pterygium. Downregulation of miR-15a might also contribute to the pathogenesis of pterygium by other mechanisms including abnormal proliferation and neovascularization, which remain to be investigated.
比较翼状胬肉和正常结膜中 miR-15a 的表达水平，并进一步探讨 miR-15a 在翼状胬肉进展中的潜在作用。
本研究纳入 21 例原发性翼状胬肉患者。应用眼前节光学相干断层扫描（AS-OCT）测量翼状胬肉侵入角膜的长度和翼状胬肉的总厚度。采集 21 例患者的翼状胬体和邻近正常结膜标本。测量 miR-15a、BCL-2、Bax 在翼状胬体和正常结膜中的表达，并分析 miR-15a 与 BCL-2、miR-15a 与 Bax、miR-15a 与临床参数之间的相关性。分离、培养翼状胬体上皮细胞（PECs），并用 miR-15a 模拟物或 miR-15a 抑制剂转染以干扰 miR-15a 的表达水平。采用实时荧光定量聚合酶链反应（RT-PCR）、Western blot 和免疫荧光法检测 BCL-2 表达的调节。采用实时荧光定量聚合酶链反应（RT-PCR）和 Western blot 检测 Bax 表达的调节。通过 CCK-8 测定法测定转染的 PECs 的细胞活力，并通过 TUNEL 测定法检测这些细胞的凋亡。
miR-15a、Bax 的表达在翼状胬体中明显降低，而 BCL-2 的表达明显升高（ < 0.05）。在翼状胬体组织中，miR-15a 的表达与 BCL-2 呈负相关（r=-0.516， < 0.05）。我们还发现，相对 miR-15a 水平与翼状胬体侵入角膜的长度呈正相关（r=-0.570， < 0.05）。在培养的 PECs 中，miR-15a 可以下调 BCL-2 的表达，上调 Bax 的表达。促进 miR-15a 可抑制培养的 PECs 的增殖并促进细胞凋亡。
本研究表明，翼状胬体中 miR-15a 的表达降低可能通过调节 BCL-2 与异常细胞的凋亡和增殖有关，从而有助于翼状胬体的发展。miR-15a 的下调可能通过其他机制（包括异常增殖和新生血管形成）也有助于翼状胬体的发病机制，这仍有待进一步研究。
