Mencucci Rita, Ambrosini Stefano, Ponchietti Claudia, Marini Mirca, Vannelli Gabriella Barbara, Menchini Ugo
Eye Clinic, Department of Oto-Neuro-Ophthalmological Surgical Sciences, University of Florence, Florence, Italy.
J Cataract Refract Surg. 2005 Nov;31(11):2180-6. doi: 10.1016/j.jcrs.2005.04.043.
To determine rabbit cornea thermal tolerance and evaluate the effects of ultrasound (US) on this tissue after applying defined US heat doses.
Eye Clinic; Anatomy Histology and Forensic Medicine, University of Florence, Florence, Italy.
Hyperthermia was induced in rabbit corneas using US, simulating a phacoemulsification procedure. The US power was set at 100% in continuous mode, and temperature values were reached within 10 seconds of the onset of US treatment. Corneal surface temperatures were continuously monitored and recorded by thermographic registration. The eyes of 16 rabbits were examined: 4 controls, 8 treated at 40 degrees C for 10 seconds, 8 treated at 50 degrees C for 10 seconds, and 12 treated at 60 degrees C for 10 seconds. All 32 corneal buttons were removed and prepared for light microscopic evaluation with hematoxylin and eosin staining, trichromic staining, and zinc iodide-osmium tetroxide solution. The 12 corneas treated at 60 degrees C for 10 seconds were also processed for immunohistochemical analysis.
Corneas at 40 degrees C for 10 seconds were grossly and histologically normal and were not different from control corneas. Corneas at 50 degrees C for 10 seconds showed initial stromal damage with collagen disorganization, mild stromal edema, and initial signs of keratocyte damage. Half of the corneas at 60 degrees C for 10 seconds were examined at time 0 and the other half after 1 week. At time 0, massive corneal damage with epithelial cell edema, collagen disorganization, severe stromal edema, intrastromal vacuole formation, plump keratocyte nuclei, and endothelial cell detachment were found, as was a severely impaired nerve plexus. At 1-week follow-up, corneas showed persistent stromal and endothelial cell edema with an increase activated keratocytes and mitotic features in the stroma and the epithelial layer.
Rabbit corneas showed a considerable tolerance to US damage up to 50 degrees C. Higher thermal doses produced severe histological damage, even though corneas showed a considerable plasticity due to their regenerative capacity.
确定兔角膜的热耐受性，并评估在施加特定超声热剂量后超声（US）对该组织的影响。
意大利佛罗伦萨大学眼科诊所；解剖学、组织学与法医学系。
使用超声诱导兔角膜热疗，模拟超声乳化手术。超声功率设置为连续模式下的100%，在超声治疗开始后10秒内达到温度值。通过热成像记录连续监测和记录角膜表面温度。检查了16只兔的眼睛：4只为对照，8只在40℃下治疗10秒，8只在50℃下治疗10秒，12只在60℃下治疗10秒。取出所有32个角膜纽扣，用苏木精和伊红染色、三色染色以及碘化锌-四氧化锇溶液进行光镜评估。对在60℃下治疗10秒的12个角膜也进行免疫组织化学分析。
在40℃下治疗10秒的角膜在大体和组织学上均正常，与对照角膜无差异。在50℃下治疗10秒的角膜显示出初始的基质损伤，伴有胶原纤维紊乱、轻度基质水肿和角膜细胞损伤的初始迹象。在60℃下治疗10秒的角膜中有一半在0时检查，另一半在1周后检查。在0时，发现角膜有大量损伤，伴有上皮细胞水肿、胶原纤维紊乱、严重基质水肿、基质内空泡形成、丰满的角膜细胞核和内皮细胞脱离，以及严重受损的神经丛。在1周随访时，角膜显示持续的基质和内皮细胞水肿，基质和上皮层中活化角膜细胞增加且有有丝分裂特征。
兔角膜对高达50℃的超声损伤具有相当的耐受性。更高的热剂量会产生严重的组织学损伤，尽管角膜由于其再生能力而具有相当的可塑性。
