Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Brisbane, Queensland 4072, Australia.
Equine Vet J. 2010 Mar;42(2):129-35. doi: 10.2746/042516409X475779.
Hyperinsulinaemia is known to induce laminitis experimentally in healthy ponies with no history of the condition. Horses are more insulin sensitive than ponies and whether prolonged hyperinsulinaemia and euglycaemia would have a similar laminitogenic effect requires study.
To determine if laminitis results when the prolonged euglycaemic hyperinsulinaemic clamp technique (p-EHC) is applied to clinically normal Standardbred horses, and to monitor hoof wall temperature seeking an association between vascular activity and laminitis development.
Eight young, clinically normal Standardbred horses were assigned into 4 pairs and within each pair, one was assigned randomly to either treatment (n = 4) or control (n = 4) groups. Treated horses received continuous infusions of insulin and glucose until clinical signs of laminitis developed, at which point the horses were subjected to euthanasia. Control horses received an equivalent volume of a balanced electrolyte infusion for the same period. Hoof wall surface temperature (HWST) was monitored continuously throughout the experimental period.
All horses in the treatment group were calculated to have normal insulin sensitivity. All treated horses, and none in the control group, developed laminitis (P = 0.01). Pronounced digital pulses were a feature of the treatment group, while insignificant digital pulses occurred in control horses. HWST was higher and less variable in treated horses once hyperinsulinaemia was established.
Healthy Standardbred horses subjected to prolonged hyperinsulinaemia develop laminitis within 48 h, demonstrating that laminitis in horses can be triggered by insulin.
Insulin resistance and the associated hyperinsulinaemia place horses and ponies at risk of developing laminitis. This study demonstrates a need for prompt management of the persistent hyperinsulinaemia seen in some endocrinopathies.
已知高胰岛素血症可在无该疾病史的健康小马中诱发实验性蹄叶炎。马比矮种马更敏感胰岛素，延长高胰岛素血症和正常血糖是否会产生类似的蹄叶炎发生作用需要研究。
确定长时间血糖正常高胰岛素钳夹技术（p-EHC）应用于临床正常的标准种马是否会导致蹄叶炎，并监测蹄壁温度，寻求血管活动与蹄叶炎发展之间的关联。
将 8 匹年轻、临床正常的标准种马分为 4 对，每对中随机分配 1 匹接受治疗（n = 4）或对照组（n = 4）。治疗组连续输注胰岛素和葡萄糖，直到出现蹄叶炎临床症状，此时对马匹进行安乐死。对照组在相同时间内接受等量的平衡电解质输注。在整个实验期间连续监测蹄壁表面温度（HWST）。
治疗组的所有马匹均被计算为具有正常胰岛素敏感性。所有治疗组的马匹均发生蹄叶炎（P = 0.01），而对照组的马匹均未发生蹄叶炎。治疗组的数字脉搏明显，而对照组的数字脉搏不明显。一旦建立高胰岛素血症，治疗组的 HWST 更高且变化更小。
接受长时间高胰岛素血症的健康标准种马在 48 小时内发生蹄叶炎，表明胰岛素可引发马的蹄叶炎。
胰岛素抵抗和相关的高胰岛素血症使马和矮种马处于发生蹄叶炎的风险之中。本研究表明，需要及时管理某些内分泌疾病中持续存在的高胰岛素血症。
