Ataallahi Mohammad, Park Geun-Woo, Park Kyu-Hyun
Department of Animal Industry Convergence, Kangwon National University, Chuncheon 24341, Korea.
J Anim Sci Technol. 2024 Nov;66(6):1237-1245. doi: 10.5187/jast.2023.e117. Epub 2024 Nov 30.
Earwax, a semi-solid substance, of both humans and non-human animals contains the stress hormone cortisol. Extraction of cortisol from earwax requires the use of organic solvents to eliminate interference factors. This study aimed to investigate the effects of organic solvents on the extraction efficiency of earwax cortisol from Hanwoo cattle. A factorial arrangement was used to determine the effects of solvent source (methyl alcohol [MA], diethyl ether [DE]) and assay diluent buffer (ADB) (0 and 1 mL) on earwax cortisol concentration (ECC) in Hanwoo cattle (parity 3, body weight = 462 kg). A 25 mg portion of the earwax sample was suspended in ADB, while another 25 mg portion was not suspended prior to extraction with MA and DE. The ECC was measured using a commercial enzyme-linked immunosorbent assay cortisol kit. The results indicated that cortisol can be extracted from earwax with or without ADB. The extraction yield of cortisol from earwax was higher with MA than with DE ( < 0.05). In conclusion, MA is the preferred solvent for cortisol extraction owing to its high extraction yield, simple extraction process, and relatively low solvent consumption. Moreover, earwax cortisol can be used as a biomarker to evaluate the degree of chronic stress in Hanwoo cattle.
耳垢是一种半固体物质，人类和非人类动物的耳垢中都含有应激激素皮质醇。从耳垢中提取皮质醇需要使用有机溶剂来消除干扰因素。本研究旨在探讨有机溶剂对韩牛耳垢皮质醇提取效率的影响。采用析因设计来确定溶剂来源（甲醇[MA]、乙醚[DE]）和分析稀释缓冲液（ADB）（0和1 mL）对韩牛（第3胎，体重 = 462 kg）耳垢皮质醇浓度（ECC）的影响。将25 mg耳垢样品部分悬浮于ADB中，而另一25 mg部分在用MA和DE提取前不悬浮。使用商用酶联免疫吸附测定皮质醇试剂盒测量ECC。结果表明，无论有无ADB，均可从耳垢中提取皮质醇。耳垢中皮质醇的提取率MA高于DE（<0.05）。总之，MA因其提取率高、提取过程简单且溶剂消耗相对较低，是皮质醇提取的首选溶剂。此外，耳垢皮质醇可作为评估韩牛慢性应激程度的生物标志物。
