Effects Of Peroxisome Proliferators-activated Receptor-γ Agonist On Expression Of NF-κB And TNF-α In Alkali-burned Corneal Of Rat

Objective To investigate the ocular application of peroxisome proliferators-activated receptor gamma (PPAR-γ) agonist pioglitazone on expression of NF-κB and TNF-αin alkali-burned corneal of rat.Methods After corneal alkali-burn models 48 Sprayue-Dawley rats were established, The rats were randomly divided into 3 groups, Group I for burned treatment group (I A:low-dose group,0.2g/L; I B:high-dose group,0.8g/L), PPAR-y agonist Pioglitazone of different concentrations were injected at the same way in IⅠA,ⅠB groups respectively for once per day. GroupⅡfor the treatment of the control group, Subconjunctival injection of dexamethasone for once per day.Ⅰ-Ⅱgroups of medication lasts 2 weeks. Normal saline was subconjunctivally injected after burning of cornea in control groupⅢ. All of right eyes for the experimental eye, and left eyes as a negative control. The growth of CNV in 48 SD rats was observed by slit lamp microscope and the area of CNV was recorded. The expression of PPAR-γ,NF-κB and TNF-αwere detected by immunohistochemistry.Results PPAR-γwas not expressed in normal rat cornea. Corneal angiogenesis was observed after alkali-burned corneas of rats, and reached the peak after 4 to 7 days. The expression of PPAR-γwas positively correlated to CNV and the expressions of NF-κB and TNF-α. The corneal neovascularization area in group I B was significantly smaller than that in the control groupsⅡ,Ⅲ(P<0.05). Compared with groupsⅡ,Ⅲ, the occurence and the growth of CNV in groupⅠB were inhibited obviousily. But no difference betweenⅠA group andⅡgroup(P>0.05). On the 4 th, 7 th,14th day, the neovasctdarization area in theⅠB group were (5.42±0.25)mm2,(8.14±0.25)mm2,(9.67±0.42)mm2, respectively. The difference was highly significant(P<0.05). more expression of PPAR-γin theⅠB group,and the expressions of NF-κB and TNF-αwere statistically declined in varying degrees and at different times (P＜0.05).Conclusion PPAR-γagonist Pioglitazone can reduce the inflammatory response of rats after alkali burn, and inhibit the growth of CNV. The mechanism may be related to activation of PPAR-γ, which reduced pro-inflammatory factor TNF-α, and inhibited of activation of NF-κB.