RESUMO
Objective To investigate whether the protective effects of leonurine (SCM-198) against endotoxin induced uveitis (EIU) of SD rats caused by lipopolysaccharide (LPS) was existing,and discuss the underlying mechanisms.Methods Thirty-six normal healthy male SD rats were divided into 3 groups randomly with the same baseline bodyweight and feeding conditions.All rats received intragastric administration every day.The experimental group was devided into 4 subgroups,rats in these subgroups received SCM-198 intragastric administration by as the dose of 10,20,40 and 80 mg/kg bodyweight per day,rats in the negative control group received intragastric administration of normal saline 10 mL/kg per day,rats in the positive control group received intragastric administration ofdexamethasone (DEX) 0.5 mg/kg bodyweight per day.All rats received a 21-day-intragastric administration.The body weight of all rats was monitored every 7 days.The electroretinogram (ERG) examination was taken in the 18th day.All rats received a 100 mg S.typhi LPS intraperitoneal injection after the 21st intragastric administration.Twenty-four hours later,following anaesthesia,all rats received another ERG examination,and inflammation was scoring under microscope by 2 experienced ophthalmologists,after that the aqueous humor of all rats was collected from the left eye.The aqueous humor was kept in-80 ℃ immediately.Then the rats were sacrificed and the right eyes were immediately enucleated to finish the HE staining and immunohistochemistry (IHC) staining examination of tumor necrosis factor-α (TNF-α) and intercellular cell adhesion molecule-1 (ICAM-1).The total amount of protein in aqueous humor was detected by BCA test.Western blot was used to examine the expression of TNF-α,interleukin-1β (IL-1β),IL-6 and ICAM-1.All data was analyzed by SPSS 19.0,and differences were considered significant at P＜0.05.Results The body weight of the rats in positive control group was significantly lower (P＜0.05) than the experimental group and the negative control group after the 21-day-intragastric administration.The inflammatory score of experimental group was lower than that of the negative control group,but higher than the score of positive control group.The HE staining sections showed the similar results.The a wave of ERG in 0.01 cd of rats received 20 mg/kg SCM-198 daily intragastric administration after LPS injection was significantly lower than that before the LPS injection (P＜0.05),also lower than other groups after LPS injection.The expression of TNF-α,IL-6 and IL-1β in the aqueous humor of the rats in the subgroup of SCM-198 10 mg/kg daily intragastric administration was lower than other groups.Conclusions Intragastric administration of SCM-198 has protective effect against endotoxin induced uveitis in SD rats without obvious adverse reaction,which could alleviate the imflammatory reaction and the damage to the uvea construction.NF-κB plays an important role in the reaction.Thus,SCM-198 is a candidate potent compound with potential therapeutic applications in inflammation associated eye diseases.While the best mode and dose of administration should be further investigated.
