目的 观察大肠杆菌内毒素脂多糖（LPS）所致兔眼内炎的临床表现，以及不同给药途径应用地塞米松治疗后的视网膜形态、功能差异。
方法 24只新西兰白兔玻璃体腔内注入LPS10μg建眼内炎模型。实验组分为球旁注射组和玻璃体腔内注射组，于建模后24h分别注射地塞米松2500μg（隔日重复，共3次） 和400μg（1次），阳性对照组及空白对照组不做干预。在建模前及LPS注入后24h到7d的不同时间点，分别对眼部炎性反应进行评估，抽取前房水检测蛋白质、LPS及地塞米松浓度，实验前及建模后7d行视网膜电流图（ERG）检查，实验结束后取视网膜标本进行荧光TUNEL和透射电镜检查。
结果 建模后24h，眼前后段均可见严重炎症反应，前房渗出率与B超下可检出的玻璃体渗出率均为100%（24/24）。实验组于建模后48h即可见炎症明显减轻，而阳性对照组炎症反应继续加重至建模后48h达高峰，此后逐渐减轻，建模后4d实验组前房渗出率12.5%（2/16），阳性对照组87.5%（7/8）。至7d各组炎症反应基本消退。第一次注射后24h，玻璃体腔内注射组前房地塞米松浓度为球旁注射组的2.79倍。7d时各组ERG较建模前有不同程度下降，阳性对照组有统计学意义（p﹤0.01）。
结论 球旁或玻璃体腔内注射地塞米松能够加快LPS诱导的兔眼内炎症的消退并减轻视网膜损伤，其中以玻璃体腔内注射次数少效果好。Purpose To investigate the clinical of endotoxin lipopolysaccharide (LPS) induced endophthalmitis in rabbits, and to compare morphology and function change of retinal in different groups which received intravitreal or sub-Tenon’s capsule injection of dexamethasone .
Methods Twenty-four New Zealand white rabbits received an intravitreal injection of LPS from Escherichia coli 10μg. Experimental group was divided into intravitreal injection group (II) and sub-Tenon’s capsule injection group (SI). After 24 hours, II group received an intravitreal injection of dexamethasone 400μg, while SI group received sub-Tenon’s capsule injections of dexamethasone 2.5 mg qod for 3 times. Positive control group (PC) received no treatment.The clinical scores, protein concentration in aqueous humor as well as LPS and dexamethasone concentration in it , were measured and compared at different time points from before LPS injection to 7 days after it. All the eyes were given Electroretinogram (ERG) examines before and after the experiment. Apoptosis of retinal cells was detected by TdT-mediated fluorescein-16-dUTP nick-end labeling (TUNEL) assay. Ultrastructure change detected by transmission electron microscope (TEM).
Results Obvious inflammatory responses were observed at time point of 24 hours after LPS injection, anterior chamber exudation and vitreous opacity were found in 24/24 eyes.In experimental group the responses visibly reduced at 48 hours, while in positive control group the most obvious at the same point. By day 4, anterior chamber exudation was found in 2/16 eyes of experimental group, while in PC group that is 7/8. By day 7, inflammation was almost cleared up, experimental and PC group showed lower ERG than before, and there was significant differences in PC group (p﹤0.01). Dexamethasone concentration in aqueous humor of II group was 1.79 times higher than SI group at 24 hours after the first injection of it .
Conclusion Both peribulbar and intravitreal injection of dexamethasone can help resolve LPS induced endophthalmitis in rabbits, and decrease function losing of retinal, intravitreal injection gives better effect by fewer treatment.