间接视神经损伤动物模型的研制

Preparation of Animal Model with Indirect Optic Nerve Injury

目的研制接近临床状态的间接视神经损伤动物模型。方法选日本大耳白兔，全麻后手术显露两侧眶上缘切迹和眶壁，咬除眶壁（深７～８ｍｍ，宽６ｍｍ），头放在致伤管下，将自制致伤卡头置于视神经孔上方眶板上，致伤球（４５ｇ）从致伤管上端自由落下（管长２ｍ），击于致伤卡头，经骨板将力传递至视神经孔致伤神经，一侧不打击作对照。致伤后瞳孔散大固定，直接光反射消失为致伤成功。结果视神经损伤发生率７６．７％，合并视神经孔骨折８０％，神经鞘膜出血５３％，鞘膜下血肿２６．７％，视神经断裂１０％。结论本模型制作方法简单易行，成功率高，骨折及鞘膜下血肿发生率与临床视神经损伤时合并情况接近，有明确的神经损伤的临床特征，是目前最接近临床损伤特征的间接视神经损伤动物模型。

Objective Vision is often seriously damaged in optic nerve injury. Most cases seen in clinics are indirect injuries. But animal model approaching the clinical features of indirect optic nerve injury has not been reported at home and abroad. Accordingly it is an urgent need to prepare an animal model for elucidation of the pathological course and for direction of clinical treatment of indirect optic nerve injury. Methods Under general anesthesia, the bilateral supra-orbital noches and orbital walls were surgically exposed. A rectangular gap on either side of orbital walls was made by excision of a portion of orbital lamina (7-8mm deep and 6 mm wide) from supra-orbital notch downwards to the optic foramen, so the underlying optic nerve was left intact. Then a self-made traumatic clamp was clamped on the upper margin of the remained orbital lamina above the optic foramen. A traumatic tube (length, 2m; inner diameter, 25mm) was perpendicalarly placed 25 mm above the traumatic clamp. Lastly, a rustless steel ball, (weight, 45 g; diameter, 22.25 mm) was dropped freely from the upper orifice of the traumatic tube and hit upon the upper surface of traumatic clamp. Occurrence of fixed pupil dilatation in company with loss of direct light reflex immediately after the struck were takenas criteria for a successful trauma. The optic nerve on the control side was not struck. Results Incidence of optic nerve injury was 76.7%. Gross anatomy, bone fractures of optic foramen 80%, hemorrhage of neurilemma 53%, subneurilemma hematoma 26% and separation of optic nerve 10%. Conclusions The method to prepare this model is simple, easy to use and of high success rate. The model, having incidence of bone fractures and subpial hematoma, similar to complications of clinical nerve injuries and definite clinical criteria for diagnosis of nerve injury, is therefore one of the most approaching clinical features of indirect optic nerve injury.