Dipartimento di Medicina Veterinaria, Università degli Studi di Milano, Lodi, Italy.
Dipartimento di Scienze Cliniche e di Comunità, Università degli Studi di Milano, Milano, Italy.
Vet Rec. 2021 May;188(9):e82. doi: 10.1002/vetr.82. Epub 2021 Feb 2.
Pain in horses is an emergent welfare concern, and its assessment represents a challenge for equine clinicians. This study aimed at improving pain assessment in horses through a convergent validation of existing tools: we investigated whether an effective analgesic treatment influences the horse grimace scale (HGS) and the concentration of specific circulating microRNAs (miRNAs).
Eleven stallions underwent routine surgical castration under general anaesthesia. They were divided into two analgesic treatment groups: castration with the administration of preoperative flunixin and castration with preoperative flunixin plus a local injection of mepivacaine into the spermatic cords. HGS and levels of seven circulating miRNAs were evaluated pre-, 8 and 20 hours post-procedure.
Compared to pre-castration, HGS, miR-126-5p, miR-145 and miR-let7e increased significantly in horses receiving flunixin at 8 hours post-castration (Friedman test, p < 0.05). Both behavioural and molecular changes occurred in horses receiving flunixin only, confirming that the addition of local mepivacaine is an effective analgesic treatment.
Combining the use of HGS and circulating miRNAs, particularly miR-145, could be meaningful to monitor acute pain conditions in horses. Our results further validate the HGS as a method to assess acute pain in horses and point out miR-145 as a promising biomarker to identify pain.
马的疼痛是一个紧急的福利问题，其评估对马科临床医生来说是一个挑战。本研究旨在通过对现有工具的收敛验证来改善马的疼痛评估：我们研究了有效的镇痛治疗是否会影响马面部表情评分（HGS）和特定循环 microRNA（miRNA）的浓度。
11 匹种马在全身麻醉下接受常规去势手术。它们被分为两组镇痛治疗：术前给予氟尼辛和术前给予氟尼辛加精索内局部注射甲哌卡因。在术前、术后 8 小时和 20 小时评估 HGS 和七种循环 miRNA 的水平。
与去势前相比，接受氟尼辛治疗的马在去势后 8 小时 HGS、miR-126-5p、miR-145 和 miR-let7e 显著升高（Friedman 检验，p<0.05）。仅接受氟尼辛治疗的马出现了行为和分子变化，证实局部甲哌卡因的添加是一种有效的镇痛治疗。
将 HGS 与循环 miRNA（特别是 miR-145）结合使用，可能对监测马的急性疼痛状况具有重要意义。我们的研究结果进一步验证了 HGS 作为评估马急性疼痛的一种方法，并指出 miR-145 是一种有前途的疼痛识别生物标志物。
