Abstract
Purpose :
Corneal collagen crosslinking (CXL) is an established technique to halt the progression of keratectasia and was recently shown to also regress mature pathologic corneal blood and lymphatic vessels in inflamed corneas. However, the effect of UVA-based CXL on corneal immune cells remains unknown. This study investigates the early and strain dependent influence of CXL on corneal immune cell populations.
Methods :
After corneal abrasion, BALB/c mice and C57BL6/N mice received a 9 minutes topical application of 0.1% riboflavin in 20% dextran phosphate sodium followed by a 9 minutes UVA irradiation (370 nm, 3 mW/ cm2) using the CCL- vario CXL system. The corneal limbus was protected by a light-preventing plastic shield. Fresh eyeballs were collected at day 1, 4, 7 (each n=5) after CXL for cryosection. Stainings for F4/80, MHC-II, CD11c were analyzed with a fluorescence microscope.
Results :
A significantly reduced amount of F4/80 + cells was observed in BALB/c mice on day 1 (p=0.012) and day 4 (p<0.001) after treatment compared to C57BL6/N mice. F4/80+ MHC-II+ cells in BALB/c (p<0.001, compared to BALB/c naïve mice) significantly went down at day 1 after CXL, whereas C57BL6/N mice showed a significant decrease (p=0.014, compared to C57BL6/N naïve mice) only at 4 days after CXL. F4/80+ MHC-II+ cells in BALB/c mice reversed to baseline on day 7. Interestingly, F4/80+ MHC-II+ cells in C57BL6/N mice remained at very low levels on day 7 after CXL.
On day 1 also the percentage of CD11c + MHC -II+ mature dendritic decreased significantly in BALB/c group (23.76%, p=0.006) compared to naïve mice (57.23%) but not in the C57BL6/N group (43.55%). On day 7 the proportion of mature dendritic cells increased in both the BALB/c group (91.02%) and C57BL6/N group (86%) equally.
Conclusions :
Our results show a strain dependent influence of CXL on corneal immune cell populations in BALB/c and C57BL/6N mice. This suggests individually different immune responses of patients after UVA-based CXL treatment and sheds light on the heterogenous outcomes of this treatment strategy.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.