Departments of Ophthalmology, and.
Clinical Chemistry, MD University of Health Sciences, Dr. Abdurrahman Yurtarslan Oncology Training and Research Hospital, Ankara, Turkey; and.
Cornea. 2020 Nov;39(11):1377-1380. doi: 10.1097/ICO.0000000000002383.
Opiorphin is an endogenous inhibitor of enkephalin-degrading enzymes. It has a strong analgesic effect in chemical and mechanical pain models. We aimed to evaluate the tear opiorphin levels in ocular pain caused by corneal foreign bodies and demonstrate whether there is any correlation with pain levels obtained from the Visual Analog Scale (VAS) score and tear opiorphin level.
Thirty-two healthy individuals and 34 individuals diagnosed with corneal foreign bodies were included in this study. Tear opiorphin levels were measured by the ELISA method using a commercially available kit. The difference in tear opiorphin levels between the patient and control groups were evaluated using the Mann-Whitney U test. The correlation between VAS scores and tear opiorphin levels was evaluated using the Spearman rank correlation coefficient.
The median values of tear opiorphin levels of the patient and control groups were 134 pg/mL (86.86-296.25) and 109.80 pg/mL (66.15-191.49), respectively. The Mann-Whitney U test showed a statistically significant difference in tear opiorphin levels between patient and control groups (P < 0.05). No ocular pain was reported in the control group. The median VAS score of the patient group was 6 points (1-9). No correlation was found between VAS scores and tear opiorphin levels in the patient group.
The cornea is the most densely innervated tissue, and the highest opiorphin concentrations have been observed in tear. It is, therefore, expected that the stimulation or damage to the nerve endings in cornea would cause an increase in opiorphin secretion as a pain relief mechanism.
阿片肽是一种内源性脑啡肽降解酶抑制剂。它在化学和机械性疼痛模型中具有很强的镇痛作用。我们旨在评估眼表疼痛（由角膜异物引起）患者的泪液阿片肽水平，并证明其与视觉模拟评分（VAS）得分和泪液阿片肽水平之间是否存在相关性。
本研究纳入了 32 名健康个体和 34 名被诊断为角膜异物的患者。使用商业上可获得的 ELISA 试剂盒通过 ELISA 法测量泪液阿片肽水平。使用 Mann-Whitney U 检验评估患者组和对照组之间泪液阿片肽水平的差异。使用 Spearman 秩相关系数评估 VAS 评分与泪液阿片肽水平之间的相关性。
患者组和对照组的泪液阿片肽水平中位数分别为 134pg/ml（86.86-296.25）和 109.80pg/ml（66.15-191.49）。Mann-Whitney U 检验显示患者组和对照组之间的泪液阿片肽水平存在统计学显著差异（P<0.05）。对照组无眼部疼痛报告。患者组的 VAS 评分中位数为 6 分（1-9）。在患者组中，未发现 VAS 评分与泪液阿片肽水平之间存在相关性。
角膜是神经分布最密集的组织，泪液中观察到的阿片肽浓度最高。因此，预计角膜神经末梢的刺激或损伤会导致阿片肽分泌增加，作为一种缓解疼痛的机制。
