Experimental Study On Low-power Semiconductor Laser Irradiation Combined With Local Drug Therapy For The Postoperative Infection After Coralline Porous Hydroxyapatite Orbital Implant Implantation

Objective: To establish the animal models with postoperative infection after CHA(coralline porous hydroxyapatite) orbital implant implantation, to observe the infected inflammatory cytokines IL-8 expression after CHA orbital implant implantation, to discuss the curative effect of combining low-power semi-conductor laser irradiation with drug therapy for the postoperative infection as well as the change of local inflammatory cytokines IL-8, and to provide a theoretical basis for curing the infection with low-power semi-conductor laser irradiation and guidance for clinical work.Methods: 12 healthy white rabbits from New Zealand were divided into two groups, labeled as A and B. In each group there were 6 rabbits. Each rabbit was kept in a single cage. The right eye of each rabbit was the experiment eye. Group A:enucleation of the right eye balls + sterile CHA orbital implant implantation; Group B:enucleation of the right eye balls + contaminated CHA orbital implant implantation;After the animal experiment model was established successfully, 24 healthy white rabbits from New Zealand were divided into four groups, labeled as C, D, E, and F. In each group there were 6 rabbits. Each rabbit was kept in a single cage, The right eye of each rabbit was the experiment eye; Group C: enucleation of the right eye balls +contaminated CHA orbital implant implantation; Group D: enucleation of the right eye balls + contaminated CHA orbital implant implantation + drug therapy; Group E:enucleation of the right eye balls + contaminated CHA orbital implant implantation +low-power semi-conductor laser irradiation(The irradiation began three days after the operation. Each irradiation lasted for 5 minutes. It was done once each day, with consecutive 5 days as a course.); Group F: enucleation of the right eye balls +contaminated CHA orbital implant implantation + drug therapy + low-power semiconductor laser irradiation(The irradiation began three days after the operation. Each irradiation lasted for 5 minutes. It was done once each day, with consecutive 5 days as a course.). After the operations, observe the following aspects with slit-lamp microscopes each day: eyelid and conjunctival hyperemia and swelling, secretion,lower eyelid ectropion, conjunctival dehiscence, orbital exposure and the range of exposure. Enzyme-linked immunosorbent assay(ELISA) was used to detect:conjunctival tissue of Group A, B on the third day after the operations and the content of IL-8 in the conjunctival tissue of Group C, D, E, and F on the eighth day after the operations. Histopathological observation: on the third day after the operations the conjunctiva and CHA orbital implant of Group A, B were taken out and on the eighth day after the operations the conjunctiva and CHA orbital implant of Group C, D, E, F were taken out. They were then fixed with 10% formalin for 24 hours, put in acidic mixed decalcification liquid for 72 hours for decalcification, embedded in paraffin,sliced sagittally, and stained with hematoxylin-eosin. At last, observing the inflammatory cell infiltration and orbital fiber vascular ingrowth under the optical microscope.Results: 1) The observation with slit lamp microscope: On the third day after the operation: Group A: eyelid and conjunctival hyperemia, edema(++), no significant secretion in conjunctival sac, conjunctival cut healing, no orbital implant exposure;Group B, C, D, E, F: eyelid and conjunctival hyperemia, edema(+++), a large number of purulent secretion in conjunctival sac, conjunctival incision dehiscence, no orbital implant exposure. On the eighth day after the operations(after one course of laser irradiation): Group C: no improvement in eyelid and conjunctival hyperemia and edema, a large number of purulent secretion in conjunctival sac, conjunctival incision dehiscence length >3mm, orbital implant exposure length ≧3mm. Group D,E: mild improvement in eyelid and conjunctival hyperemia and edema, a large number of purulent secretion in conjunctival sac, conjunctival incision dehiscence length >3mm, orbital implant exposure length ≧ 3mm.Group F: significant improvement in eyelid and conjunctival hyperemia and edema, small amount of secretion, conjunctival cut healing, no orbital implant exposure. 2) The detection of IL-8 with enzyme-linked immunosorbent assay(ELISA): For the content of the inflammatory cytokines IL-8 in conjunctival tissue, SPSS 19.0 statistical software was used for t test which showed that there was significant difference between Group A and Group B. The t value was 19.067 and p was O.000, which indicated that the difference had statistical significance; there was also significant difference betweengroup F and the groups C, D and E using analysis of variance with SPSS 19.0software. The f value was 68.239 and p was O.000, which indicated that the difference had statistical significance; multiple comparisons were made among Group C, D, E and there existed differences, but p was more than O.05, so these differences had no statistical significance. 3) Histopathological observation: There were a few inflammatory cells in the conjuntival tissue and the CHA orbital implant of Group A or the inflammatory cells were not obvious. A large number of inflammatory cells could be seen in the conjuntival tissue and the CHA orbital implant of Group B; there were a lot of inflammatory cells in the conjuntival tissue and the CHA orbital implant of Group C, D, E and almost no fiber vascular ingrowth in the CHA orbital implant;there were few inflammatory cells in the conjuntival tissue and the CHA orbital implant of Group F or the inflammatory cells were not obvious, and there was significant fiber vascular ingrowth in the CHA orbital implant than group C, D, E.Conclusions: 1)To establish the animal models with postoperative infection after CHA(coralline porous hydroxyapatite) orbital implant implantation, It indicates that the content of postoperative IL-8 of infected CHA orbital implant is significantly higher than that of the uninfected CHA orbital implant. 2) Combining low-power semi-conductor laser irradiation with drug therapy for curing the postoperative infection not only has obvious effect but also is safe. It can decrease the inflammatory cytokines IL-8 level, effectively control the infection, and prevent the conjunctival dehiscence and orbital implant exposure, but only laser irradiation or only drug therapy for curing local infection has no significant effect.