The Healing Process In Repair Of Lacrimal Canalicular By Autogenous Vein Graft In Rabbits

ObjectiveDisjunction of lacrimal canaliculus, especially the lower canaliculus, are often associated with severe eyelid trauma. If the injury of the lacrimal duct couldn't be repaired by surgery, it may leads to scarring and stenosis, which, in turn, causes permanent epiphora, and brings great unset to patient. Anastomosis of ruptured lacrimal canaliculus is the standard surgical procedures at present. But, when the patients were with serious injury, excessive granulation tissue or scar formation and canaliculus defect, direct anastomosis can't be achieved. From 1960s, the method of using autogenous vein graft to reconstruct lacrimal canaliculus is reported continuously. There are many theses on clinical applications, but little on experimental study.In this experiment, an animal model with lacrimal canaliculus disjunction was made in rabbit by intersecting the lacrimal canaliculus. The canaliculus injury was repaired by end-to-end anastomosis and autogenous vein graft. The healing process in anastomosis region after surgery was observed.Materials and Methods1 Animal and grouping64 healthy adult albino rabbits without eye diseases were divided into 3 groups randomly: normal control group, simple anastomosis group and autogenous vein graft group. Among of them, 8 eyes of 4 rabbits were randomly assigned as the normal control group, another 60 rabbits(120 eyes) were divided into 2 surgery group(one eye is in simple anastomosis group and another is in autogenous vein graft group of each rabbit), 60 eyes in each group.2 Methods of surgeryAn animal model with lacrimal canaliculus disjunction was made by intersected the lacrimal canaliculus. With the silicon tube as bracket, the canaliculus injury was repaired by end-to-end anastomosis in simple anastomosis group, and by autogenous vein graft in graft group. Normal control group was not operated with.3 Observation items and timePostoperative patent information of lacrimal drainage system(fluorescein disappearance test and irrigation test) were examined at 1d, 3d, 5d, 7d, 14d and 28d after surgery. The pathological changes of anastomosis region were observed by general observing and routine HE stain. The degree of cell multiplication in anastomosis region was measured by calculating positive cell rate of proliferating cell nuclear antigen(PCNA). Normal control group was observed with same items.4 Statistical analysisStatistical analysis was performed with SPSS 11.0 software. Simple anastomosis group and autogenous vein graft group were compared using t-test, simple anastomosis group, autogenous vein graft group and normal control group were compared using one-way analysis of variance.Results1 Postoperative patent information of lacrimal drainage systemAutograft vein group at 7 day post-operative, simple anastomosis group at 5 day post-operative, lacrimal passage have recovered the function of lacrimal passage, the interval time of a positive result of fluorescein disappearance test (FDT) has no significant differences among normal control group, simple anastomosis group and autogenous vein graft group (P>0.05).2 Healing process of anastomosis region after surgery2. 1 General observingAt 1, 3 day post-operative, there were obvious edema and effusion in the anastomosis region. At 5 day post-operative, the anastomosis region in autograft vein group was clear, but in simple anastomosis group was fuzzy. The anastomosis region couldn't be seen clearly at 7 day post-operative. At 28 day post-operative, the anastomosis region could be discriminated only by suture line.2. 2 Pathological changes of anastomosis regionIn autograft vein group: at 3 day post-operative, endothelial cells of autograft vein in anastomosis region began to fall off, and endothelial cells of lacrimal canaliculus migrated; at 5 day post-operative, smooth muscle cells degenerated and collagenoblast cells proliferated in anastomosis region autograft vein; at 7 day post-operative, anastomosis region has completely been covered with canalicular epithelia; at 28 day post-operative, the epithelial proliferation stabilized, but there were still many fibroblast cells in propria lamina.In simple anastomosis group: epithelia completely covered the anastomosis region at 5 day post-operative, the epithelial proliferation stabilized at 14 day post-operative, considerable collagenous fibers were detected in propria lamina at 28 day post-operative.2. 3 Result of immunohistochemistryAt 3 day post-operative, PCNA positive rate in both of the epithelial cell and fibroblast cell began to obviously increase, and reached a peak at 7 day post-operative in vein autograft group, at 5 day post-operative in simple anastomosis group. After that, the rate decreased gradually.At 5 day post-operative, in vein autograft group, PCNA positive rate in both of the epithelial cell and fibroblast cell are less than in simple anastomosis group(P<0.01). PCNA positive rate of fibroblast cell in autogenous vein graft group is more than both in simple anastomosis group and normal control groupat 28 day post-operative(P<0.05).Conculsions1. Repairing lacrimal canaliculus by autogenous vein graft at 7 days post-operative, and simple anastomosis at 5 day post-operative, lacrimal passage have recovered the function of lacrimal passage.2. Compared with simple anstomosis, the healing process in repair of the lacrimal canalicular by autogenous vein graft is more complex and longer.3. Endothelial cells of autograft vein in anastomosis region fall off, endothelial cells of lacrimal canaliculus migrate and cover defective region; smooth muscle cells degenerate and collagenoblast cells proliferate.