Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
SMART Pharmacology, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
Vet Ophthalmol. 2021 Jul;24(4):425-428. doi: 10.1111/vop.12876. Epub 2021 Mar 15.
Determine the protein content and volume of tears sampled by Schirmer strips wetness ranging from 20 to 35 mm.
Ten healthy beagle dogs.
Each dog underwent 20 tear collections per day (10 sessions in each eye, spaced by ≥1 h) for 4 separate days, providing 200 tear samples for each length of wetness evaluated: 20, 25, 30, and 35 mm. A Schirmer strip was placed in each eye until the selected mm-mark was reached, calculating the volume absorbed (VA) as the difference between the post- and pre-collection weight (assuming 1 mg~1 µL for tear fluid), and the volume recovered (VR) as the amount pipetted from the tube following centrifugation. Total protein content (TPC) was measured with infrared spectroscopy. Outcome measures were compared with the Kruskal-Wallis test.
Median values for VA (µL), VR (µL) and TPC (mg/mL) were as follows: 20 mm (18, 10, 5.94), 25 mm (22, 12.5, 5.97), 30 mm (25.5, 16, 5.89), and 35 mm (31, 22.5, 7.13). Both VA and VR were significantly greater (p < .001) for Schirmer strips wetness of 35»30»25»20 mm. TPC was significantly greater (p < .001) for 35 > 20-30 mm, but not among other groups (p = 1.000).
The study established normative data to consider when canine studies use Schirmer strips to collect tears for bioanalytical purposes (eg, proteomics, pharmacokinetics). Although 35 mm yielded higher VA and VR, the higher TPC could be explained by greater disruption of ocular surface homeostasis. Absorption to 20-30 mm is the suggested length of strip wetness for bioanalytical tear collection in dogs.
确定 Schirmer 条湿润长度为 20 至 35mm 时所采集的泪液的蛋白含量和体积。
10 只健康比格犬。
每只狗每天进行 20 次泪液采集（每只眼 10 次，间隔≥1h），共 4 天，为每种湿润长度评估提供 200 个泪液样本：20mm、25mm、30mm 和 35mm。将 Schirmer 条放置在每只眼睛中，直到达到所选的 mm 标记，通过收集前后重量的差异（假设泪液的 1mg~1µL）来计算吸收的体积（VA），并通过离心后从管中吸取的量来计算恢复的体积（VR）。采用红外光谱法测量总蛋白含量（TPC）。使用 Kruskal-Wallis 检验比较结果。
VA（µL）、VR（µL）和 TPC（mg/mL）的中位数分别为：20mm（18，10，5.94）、25mm（22，12.5，5.97）、30mm（25.5，16，5.89）和 35mm（31，22.5，7.13）。Schirmer 条湿润长度为 35mm、30mm、25mm、20mm 时，VA 和 VR 均显著更高（p<0.001）。TPC 在 35mm>20-30mm 时显著更高（p<0.001），但在其他组之间无差异（p=1.000）。
本研究为犬类研究使用 Schirmer 条采集用于生物分析目的（例如蛋白质组学、药代动力学）的泪液时提供了参考标准数据。尽管 35mm 条可产生更高的 VA 和 VR，但 TPC 更高可能是由于眼表面内稳态受到更大的破坏。对于犬类生物分析泪液采集，建议的 Schirmer 条湿润长度为 20-30mm。
