Primary Study On The Establish Of Animal Model Of Chronic Dacryocystitis In Rabbits

Objective: Explore the successful methods to establish animal model of chronicdacryocystitis in rabbits, and analyze related influence factors of successful model.Methods:55rabbits were randomly divided into A, B, C, D, E five groups,11rabbits ineach group, and the right eyes were the experimental eyes. Group A was a temporaryobstruction of lacrimal passage group by using TDI olive oil to induce allergic rhinitis.Group B was a simple bacterial inoculation group with infusion of Staphylococcus aureusbacterial suspension (107cells/ml). Group C was a permanent lacrimal duct obstructiongroup by injection of MMA and PMMA mixture through lacrimal punctum. Group D wasalso a permanent lacrimal duct obstruction group with the injection of MMA and PMMAmixture combined with infusion of Staphylococcus aureus bacterial suspension (107cells/ml). Group E was the normal control group with injection of sterile saline solution throughlacrimal punctum. Clinical manifestations of the five groups were observed. Following testswere executed on those rabbits with chronic dacryocystitis clinic manifestations and failurein syringing of the lacrimal passges, including bacterial culture and identification oflacrimal secretions, conventional histopathological and ultrastructural pathologyexamination of the nasolacrimal duct and lacrimal sac organization and lacrimal CTangiography. We analyze the influence factors related to the successful model of chronic dacryocystitis by statistics on the incidence of chronic dacryocystitisResults: In these five groups, rabbits of A, B and E groups showed no clinicalmanifestations of chronic dacryocystitis, and syringing of the lacrimal passges were patent.The amounts of the rabbits appeared chronic dacryocystitis clinical manifestations in groupC and D were respectively8(successful rate of8/11,72.7%) and9(9/11,81.8%). Thoseanimals whicc failed in syringing of the lacrimal passges began to appear similar clinicalsymptoms of chronic dacryocystitis including tearing, and secretions increasing more than aweek after modeling and the time when appeared chronic dacryocystitis clinicmanifestation of animals of group C was also similar to that of group D. The results wereobtained by bacterial culture and identification of lacrimal secretions that Pasteur colidetection rate was100%, but the Staphylococcus aureus was predominate in group D. Theroutine pathology manifested lacrimal sac and nasolacrimal duct lumen with differentdegrees of exudate, epithelial cell proliferation, and visible nests of lymphoid follicles inthe lacrimal sac epithelium, degeneration of elastic fibers and collagen fibers, proliferationand disoder of fibrous connective tissue, infiltration of plasma cells, highly dilatedcongestive capillary lumen. The ultrastructural pathology manifested edema of columnarepithelial cells in nasolacrimal duct mucosa, a proliferation of mitochondria andendoplasmic reticulum dilation, visible bacteria particles, neutrophil infiltration, edema oflacrimal epithelial cells in lacrimal sac, less microvilli in cell surface, visible inflammatorycell infiltration in intracellular. nasolacrimal duct mucosa with abundant fibrous connectivetissue derangement, fibrous hyperplasia, inflammatory cell infiltration in lacrimal sac,mainly lymphocytes, plasma cells and neutrophils. CT angiography clearly displayed theobstruction site of nasolacrimal duct and the degree of obstruction.Conclusion: The pure bacterial inoculation and temporary lacrimal duct obstruction can notresult in rabbits with chronic dacryocystitis, permanent obstruction of the lacrimal ductcombined with or without bacterial inoculation may result in70%-80%rabbits that showedchronic dacryocystitis clinic manifestation, positive bacterial cultures, cell structure and morphology changes of the chronic inflammatory in conventional histopathological andultrastructural pathology, and obstruction of the nasolacrimal duct displayed on lacrimal CTangiography. These aspects mentioned above tip for successful establishment of animalmodel of chronic dacryocystitis in rabbits. The complete lacrimal duct obstruction was thebasic condition for the formation of chronic dacryocystitis.