Abstract
Purpose :
To evaluate the protective effect of 0.4% sodium hyaluronate on benzalkonium chloride-induced toxicity using an in vivo model.
Methods :
88 Balb/c mice were divided into 4 groups: 1) Control: saline solution; 2) SH: 0.4% sodium hyaluronate 3 times a day; 3) BAK: benzalkonium chloride 0.01% twice a day; 4) SH+BAK: SH 0.4% 3 times a day + BAK 0.01% twice a day. All groups received 3 daily instillations (8AM, 2PM, and 8PM). For the SH+BAK group, SH was administered first and BAK was administered 10 minutes later. The dosing scheme began 48 hours before time 0 when a controlled, 1.5 mm-diameter corneal ulcer was made under a surgical microscope in the right eye of all mice. The dosing schedule continued for 10 days. After this period, all mice were sacrificed and the corneal nerve plexus was analyzed by confocal microscopy, with βIII tubulin immunostaining. Wound healing over time and corneal nerve regeneration using Sholl analysis were assessed. Data were analyzed by two-way ANOVA.
Results :
Wound closure: There were statistically significant differences in ulcer closure between treatment groups over time (p<0.0001). Mice treated with BAK show slower healing than those treated with SH+BAK (p=0.0124).The AUC of corneal cicatrization for Control group was 19.7±2.5; for SH 20.1±2.7; for BAK 28.0±4.6, and for SH+BAK 24.4±5.0 (p<0.001). All ulcers closed within 72 hours of injury. The media of hour of wound closure was: 41.5±9.6 for control group; 39.3±7.6 for SH group; 51.3±9.9 for BAK group, and 45.8±8.8 for SH+BAK group. (p<0.001).
Corneal nerve regeneration: The neural network presented an increasing complexity in the groups: BAK < BAK+SH < CONTROL < SH. Considering the largest radius analyzed (100 µm), the number of intersections was: 11.5 ± 2.6 in Control group; 15.8 ±2.1 in SH; 5.1 ± 2.2 in BAK, and 8.05 ± 2.2 in SH+BAK (p <0.05). The AUC of corneal cicatrization for Control group was 19.7±2.5; for SH 20.1±2.7; for BAK 28.0±4.6, and for SH+BAK 24.4±5.0 (p<0.001). All ulcers closed within 72 hours of injury. The media of hour of wound closure was: 41.5±9.6 for control group; 39.3±7.6 for SH group; 51.3±9.9 for BAK group, and 45.8±8.8 for SH+BAK group (p<0.001).
Conclusions :
BAK has a toxic action both on epithelial regeneration and corneal nerve plexus.
The concomitant addition of SH protects against the toxic action of BAK, promoting epithelial healing and corneal nerve regeneration.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.