兔慢性泪囊炎动物模型建立的方法学研究

背景 慢性泪囊炎是一种常见的泪器感染性疾病,易复发,导致患者预后较差.目前关于在病变复发过程中究竟是感染因素还是泪道阻塞因素发挥主要作用仍存在争议,建立合理的动物模型有助于其发病机制的研究,但目前鲜见慢性泪囊炎的建立方法研究. 目的 探索建立兔慢性泪囊炎动物模型的方法,为慢性泪囊炎的临床诊疗研究提供实验依据.方法 采用随机数字表法将66只日本大耳白兔随机分为6个组,每组11只,均以右眼作为实验眼.暂时泪道阻塞组采用质量分数10％甲苯-2.4-二异氰酸酯(TDI)联合榄橄油溶液右鼻腔滴鼻诱导过敏性鼻炎造成暂时性泪道阻塞;永久泪道阻塞组由泪点注入0.15 ml甲基丙烯酸甲酯(MMA)和聚甲基丙烯酸甲酯(PMMA)聚合物;单纯细菌接种组由泪点注入1×107/ml金黄色葡萄球菌悬液0.3 ml;暂时泪道阻塞+细菌组和永久泪道阻塞+细菌组分别在造成暂时性泪道阻塞和永久性泪道阻塞后次日由泪点注入1×107/ml金黄色葡萄球菌悬液0.3 ml;正常对照组由兔泪点注入0.3 ml生理盐水.分别于术前、术后即刻及术后1d、7d观察动物出现慢性泪囊炎的眼部表现情况以判断造模成功率,行泪道冲洗观察泪道是否通畅,并行泪道CT造影检查是否发生泪道阻塞、阻塞部位以及阻塞程度;术后7d行泪道和泪囊黏膜的常规组织病理学检查. 结果 造模后3个月,暂时泪道阻塞组、单纯细菌接种组、暂时泪道阻塞+细菌组和正常对照组无一例出现慢性泪囊炎表现,永久泪道阻塞组和永久泪道阻塞+细菌组分别有8只眼和9只眼出现慢性泪囊炎的症状和体征.泪道冲洗结果提示,永久泪道阻塞组和永久泪道阻塞+细菌组的慢性泪囊炎眼泪道冲洗不通畅,液体完全返流;泪道CT造影检查显示,兔鼻泪管阻塞部位为鼻泪管的远端,即鼻泪管骨内段与鼻内段的转折部位,并可见鼻泪管完全阻塞,阻塞处近端可见明显的鼻泪管扩张,阻塞处远端无明显的造影剂充盈;永久泪道阻塞组模型眼标本可检出革兰阴性杆菌,永久泪道阻塞+细菌组模型眼金黄色葡萄球菌为优势菌.暂时泪道阻塞组、单纯细菌组、暂时泪道阻塞+细菌组和正常对照组兔眼泪囊和泪道黏膜病理组织学检查未发现异常,而永久泪道阻塞组和永久泪道阻塞+细菌组模型眼标本可见炎性细胞浸润和增生性改变.结论 泪道永久性阻塞是兔慢性泪囊炎动物模型建立的必要条件,在兔慢性泪囊炎的发生中起关键作用.

Methodology of a rabbit model of chronic dacryocystitis

Background Chronic dacryocystitis is a common infectious lacrimal apparatus disease.Whether infection factors or lacrimal duct obstruction play a major role in the process of recurrent lesions is still controversial.Establishing a reasonable animal model contributes to its pathogenesis study.However,an effective methodology on establishing chronic dacryocystitis animal model is lack.Objective This study was to develop a method of establishing chronic dacryocystitis animal model.Methods Sixty-six Japanese white rabbits were randomized into 6 groups and 11 for each,and the right eye of each rabbit served as the experimental eye.The solution of 2,4-toluene disocyanate (TDI) with olive oil was droped in the right nasal cavity to induce allergic rhinitis in the temporary lacrimal duct obstruction group;0.15 ml mixture of methyl methacrylate (MMA) with polymethyl methacrylate (PMMA) was injected into lacrimal duct via lacrimal punctum in the permanent lacrimal duct obstruction group;0.3 ml Staphylococcus aureus suspension at the concentration of 1 × 107/ml was injected into lacrimal duct via punctum in the only bacterial inoculation group,and the Staphylococcus aureus suspension was injected folowing the operation of allergic rhinitis or mixture of MMA injection respectively in the temporary lacrimal duct obstruction+bacterial group and permanent lacrimal duct obstruction+bacterial group.An equal volume of sterile saline solution was injected into the lacrimal duct in the normal control group.The clinical manifestations were observed before operation,immediately at operation,1 day and 7 days after operation as a criteria of model of chronic dacryocystitis.Sringing of lacrimal duct was performed to evaluate the lacrimal patency,and parallel lacrimal CT angiography of lacrimal duct was carried out to identify the location of obstruction.The specimens of lacrimal sac and duct walls were collected for the bactriology and histopathology examination.The use and care of the experimental amnimals comlied with ARVO Statement.Results The animals were observed for consecutive 3 months.No chronic dacryocystitis occurred in the temporary lacrimal duct obstruction group,only bacterial inoculation group,temporary lacrimal duct obstruction+bacterial group and normal control group.The chronic dacryocystitis models were successfully established in 8 eyes in the permanent lacrimal duct obstruction group and 9 eyes in the permanent lacrimal duct obstruction+bacterial group.The lacrimal duct was closed,with the liquid completely reflux in the model eyes by sringing of lacrimal duct.Lacrimal CT angiography displayed the visible completely blockage of nasolacrimal duct in nasolacrimal duct distal namely nasolacrimal duct bone and nasal segment of the turning point and a visible expansion of proximal of obstructive site.Gram-negative bacilli were found in the models of the permanent lacrimal duct obstruction group and Staphylococcus aureus was dominant bacteria in the permanent lacrimal duct obstruction+bacterial group.No abnormality was found in the specimens from temporary lacrimal duct obstruction group,only bacterial inoculation group,temporary lacrimal duct obstruction+bacterial group and normal control group,and infiltration of inflammatory cells and proliferatin of mucosa were seen in the model eyes of permanent lacrimal duct obstruction group and permanent lacrimal duct obstruction+bacterial group.Conclusions Permanent obstruction of lacrimal duct is a necessary condition to the establishment of animal model of chronic dacryocystitis,which plays a key role in the occurrence of rabbit chronic dacryocystitis.