Monitoring of strain-dependent responsiveness to TLR activation in the mouse anterior segment using SD-OCT.
PURPOSE
To determine whether spectral-domain optical coherence tomography (SD-OCT) can be used to longitudinally monitor inflammation in the mouse anterior segment and to identify any strain-dependent differences in responsiveness to distinct toll-like receptor (TLR) ligands.


METHODS
Corneal inflammation was induced in BALB/c and C57BL/6 mice following central corneal abrasions and topical application of saline, TLR-4 ligand, lipopolysaccharide (LPS), or TLR-9 ligand, CpG-oligodeoxynucleotide (CpG-ODN; CpG). Anterior-segment images were captured using SD-OCT at baseline, 24 hours, and 1 week post treatment. Corneal thickness, stromal haze, and the number of keratic precipitates (KP) and anterior chamber (AC) cells were longitudinally compared to determine differences between mouse strains, time points, and TLR activation.


RESULTS
In both mouse strains, treatment with CpG, but not saline or LPS, resulted in a similar number of KPs and AC cells. In C57BL/6 mice, central corneal thickness (CCT) increased in CpG- and LPS-treated eyes at 24 hours, which normalized by 1 week. In BALB/c mice, a significant increase in CCT occurred in eyes treated with CpG at 1 week. Stromal haze peaked in C57BL/6 eyes treated with LPS- or CPG-treatment at 24 hours; however, BALB/c eyes showed persistent and marked increases in corneal haze compared with baseline at 1 week post treatment.


CONCLUSIONS
Spectral-domain OCT enables high-resolution, longitudinal, in vivo imaging of anterior segment inflammation in mice and revealed novel strain- and time-dependent differences in response to distinct TLR activation in the cornea.
['Downie|Laura Elizabeth|LE|', 'Stainer|Matthew James|MJ|', 'Chinnery|Holly Rose|HR|']
D000704:Analysis of Variance D000818:Animals D000867:Anterior Chamber D000869:Anterior Eye Segment D015715:Corneal Edema D003319:Corneal Stroma D004195:Disease Models, Animal D005260:Female D008070:Lipopolysaccharides D008137:Longitudinal Studies D051379:Mice D008807:Mice, Inbred BALB C D008810:Mice, Inbred C57BL D009838:Oligodeoxyribonucleotides D051197:Toll-Like Receptor 4 D051217:Toll-Like Receptor 9 D041623:Tomography, Optical Coherence
SD-OCT inflammation toll-like receptors imaging cornea