Johnson Philip J, Slight Simon H, Ganjam Venkataseshu K, Kreeger John M
Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Clydesdale Hall, Columbia, MO 65211, USA.
Vet Clin North Am Equine Pract. 2002 Aug;18(2):219-36. doi: 10.1016/s0749-0739(02)00015-9.
The administration of exogenously administered GCs and syndromes associated with GC excess are both attended by increased risk for the development of laminitis in adult horses. However, there exists substantial controversy as to whether excess GCs cause laminitis de novo. If true, the pathogenesis of laminitis arising from the effects of GC excess is probably different from that associated with diseases of the gastrointestinal tract and endotoxemia. Although a satisfactory explanation for the development of laminitis as a consequence of GC action is currently lacking, numerous possible and plausible theoretical mechanisms do exist. Veterinarians must exert caution with respect to the use of GCs in adult horses. The extent to which individual horses are predisposed to laminitis as a result of GC effect cannot be predicted based on current information. However, the administration of systemic GCs to horses that have been previously affected by laminitis should be used only with extreme caution, and should be accompanied by careful monitoring for further signs of laminitis. The risk of laminitis appears to be greater during treatment using some GCs (especially dexamethasone and triamcinalone) compared with others (prednisone and prednisolone). Whenever possible, to reduce the risk of laminitis, GCs should be administered locally. For example, the risk of GC-associated laminitis is evidently considerably reduced in horses affected with chronic obstructive pulmonary disease (COPD) if GC treatment is administered via inhalation. We have hypothesized that structural changes in the equine hoof that resemble laminitis may arise as a consequence of excess GC effect. Although these changes are not painful per se, and are not associated with inflammation, they could likely predispose affected horses to the development of bona fide laminitis for other reasons. Moreover, the gross morphological appearance of the chronically GC-affected hoof resembles that of a chronically foundered hoof in some respects. Further investigation into the effect of GC on the hoof lamellar interface is clearly needed.
外源性给予糖皮质激素（GCs）以及与GCs过量相关的综合征，都会使成年马发生蹄叶炎的风险增加。然而，关于GCs过量是否会直接引发蹄叶炎，存在大量争议。如果确实如此，由GCs过量效应引起的蹄叶炎发病机制可能与胃肠道疾病和内毒素血症相关的发病机制不同。尽管目前尚缺乏对GCs作用导致蹄叶炎发生的令人满意的解释，但确实存在许多可能且合理的理论机制。兽医在成年马中使用GCs时必须谨慎。根据目前的信息，无法预测个体马因GCs效应而患蹄叶炎的易感性程度。然而，对于先前已患蹄叶炎的马，全身性给予GCs时应极其谨慎，并应密切监测是否有蹄叶炎的进一步迹象。与其他GCs（泼尼松和泼尼松龙）相比，使用某些GCs（尤其是地塞米松和曲安西龙）治疗期间，蹄叶炎的风险似乎更高。只要有可能，为降低蹄叶炎风险，应局部给予GCs。例如，如果通过吸入方式给予GCs治疗，患有慢性阻塞性肺疾病（COPD）的马发生GCs相关蹄叶炎的风险显然会大幅降低。我们推测，马的蹄部出现类似蹄叶炎的结构变化可能是GCs过量效应的结果。尽管这些变化本身并不疼痛，也与炎症无关，但它们可能会使受影响的马因其他原因而更易发生真正的蹄叶炎。此外，长期受GCs影响的蹄部大体形态外观在某些方面类似于长期患蹄叶炎的蹄部。显然需要进一步研究GCs对蹄叶层界面的影响。
