Amelioration Of Endotoxin-induced Uveitis Treated With An Ikb Kinase Inhibitor, Imd-0354 In Rats

Abstract

 

Purpose:

 

Endotoxin-induced uveitis (EIU) is an animal model for acute ocular inflammation. Nuclear factor-kappa B (NF-ΚB) plays a key role to induce inflammation. Inactive NF-ΚB complexed with inhibitor of kappa B (IΚB) and activated by degradation of IΚB by IΚB kinases (IKKs). IMD-0354 is one of the IKK inhibitors which down-regulates NF-ΚB activation. In the present study, we examined whether administration of new IKKβ inhibitor IMD-0354 has therapeutic effects on EIU in rats.

 

Methods:

 

Six-week-old male Lewis rats were used. EIU was induced by subcutaneous injection of 200 μg of LPS from Escherichia Coli. Immediately, rats were administered 30, 10, 3 or 0 mg/kg of body weight of IMD-0354 intraperitoneally. At 24 hours after LPS injection, the aqueous humor was collected. Total aqueous protein concentrations were quantified and cell numbers were counted. Also eyes were fixed with PFA 4% via intracardial injection and immunohistochemically stained with anti-NFΚB antibodies.

 

Results:

 

Aqueous protein concentrations were 92.5±5.3, 101.5±11.7, 112.6±3.2 and 117.3±3.0 µg/ml in rats treated with 30, 10, 3 or 0 mg/kg of IMD-0354, respectively. It was significantly lower in rats treated with 30 mg/kg and 10 mg/kg of IMD-0354 compared with controls (P<0.01). Mean aqueous protein concentration was 21.5±4.7 in naïve rats. The numbers of inflammatory cells in aqueous humor were 46.4±16.8, 68.25±30.1, 128.41±54.9, and 133.3±44.0 in rats treated with 30, 10, 3 or 0 mg/kg of IMD-0354, respectively. Significantly fewer aqueous inflammatory cells were counted in rats treated with 30 and 10 mg/kg of IMD-0354 than controls (P<0.05). NF-ΚBp65 positive nuclei (yellow) in ciliary body were detected as 249.0±27.8 in untreated eyes (Image 1,B), but only 146.6±3.0 in 30 mg/kg IMD-0354-treated rats (Image 1,A) (P<0.01). No NF-ΚBp65 positive nuclei were detected in Naïve eyes (Image 1,C).

 

Conclusions:

 

It was demonstrated that acute intraocular inflammation was ameliorated by inhibition of IKK/NF-ΚB pathway. IMD-1041, a prodrug for IMD-0354, also showed similar anti-inflammatory effect with oral application in EIU model (Data is not shown).Therefore IKKβ phosphorylation inhibitor might be a promising substance for treatment of uveitis and other intraocular inflammation.  

 

Keywords: inflammation • uveitis-clinical/animal model • enzymes/enzyme inhibitors