Abstract
Purpose:
Fibrosis is a common outcome of inappropriate tissue repair and responsible for corneal blindness often as the aftermath of infections or trauma. The goal of this study was to understand the relationship between fibrosis and inflammation following infection or trauma. To this end mouse models of fibrosis associated with infection and trauma were developed.
Methods:
A mouse model with corneal fibrosis triggered by infection (IF) (Pseudomonas aeruginosa) or anterior keratectomy (AK) was used. Real Time PCR was used to examine the expression of αSMA, HMGB1, RAGE and S100A8/9 in the isolated cornea stroma at postoperative times (PO) 6h, 16h, 2, 7 and 14 days (D). A multiplex cytokine assay was used to examine the expression of IFNγ, IL6, MIP2, MIP1a, MIP1b, GCSF, VEGF and RANTES in the isolated cornea stroma and tears at PO 2, 7, 14D and 4 weeks (W). Ten mice were used for each time point.
Results:
RT-PCR of stroma after IF or AK, compared with normal stroma (N), showed that RAGE and S100A8/9 increased and peaked at PO16h (RAGE: 2.5 fold increased after AK and 5.6 fold after IF; S100A8:134 fold after AK and 95 fold after IF; S100A9:145 fold after AK and 97 fold after IF; p<0.05); αSMA increased and peaked at PO 7D (6 fold after AK and 10 fold after IF, p<0.05); HMGB1 was downregulated from PO 6h to 14D (0.13 fold after AK and 0.12 fold after IF at PO 7D, p<0.05). The multiplex cytokine assay of stroma, compared with N, showed VEGF (46 fold increased after AK and 52 fold after IF, p<0.05), IL6 (17 fold after AK and 22 fold after IF, p<0.05), MIP2 (4711 pg/ml after AK and 9123 pg/ml after IF, NDN (not detected in N), MIP1a (1777 pg/ml after AK and 3878 pg/ml after IF, NDN), MIP1b (459 pg/ml after AK and 724 pg/ml after IF, NDN) and GCSF (841 pg/ml after AK and 1109 pg/ml after IF, NDN) increased at PO 2D; IFNγ increased at PO 4W (3.8 fold after AK and 1.2 fold after IF, p<0.05). The multiplex cytokine assay of tears, compared to normal tears (NT), showed IL6 (46 pg/ml, ND in NT), MIP1a (8.5 pg/ml, ND in NT), MIP1b (93 pg/ml, ND in NT), and MIP2 (51 pg/ml, ND in NT) increased after AK at PO 4W; GCSF (4 fold, p<0.05, ND in NT) increased after AK at PO 2W; VEGF was downregulated after AK or IF.
Conclusions:
Similarities have been shown between the inflammatory changes associated with a corneal infection and trauma in mouse models for both proinflammatory peptides such as the S100 peptides as well as critical cytokines.