Short-term effects of argon cold atmospheric plasma on canine corneas ex vivo

Juliane Dick ¹ Sandra Lockow ² Wolfgang Baumgärtner ² Holger Andreas Volk ¹ Claudia Busse ^1*

• ¹ Small Animal Clinic, University of Veterinary Medicine Hanover Foundation, Hannover, Germany
• ² Department of Pathology, University of Veterinary Medicine, Foundation, Hannover, Germany

Purpose: To analyse the effects of argon cold atmospheric plasma (CAP) on canine corneas.Methods: Healthy canine eyes (n=20) were subjected to a keratectomy (5x7mm, 400µm) and divided into two control (c0c1 -not cultured; t0 -cultured) and two treatment groups (t2, t5treatment of 2 or 5 minutes, cultured); n = 5 eyes each. The kINPen® VET (neoplas GmbH, Greifswald, Germany) was used for CAP treatment. Corneas (t0, t2, t5) were cultured at an airliquid interface (72 hrs). Histopathological and immunohistochemical (Ki-67, Caspase-3, α-SMA) examinations were performed.Results: Corneal epithelization was complete and epithelial thickness was similar in all eyes.The number of perilimbal epithelial cell nuclei varied between groups with c0c1 = 22 ± 6, t0 = 13 ± 5, t2 = 15 ± 5 and t5 = 10 ± 4 nuclei/randomized fields and was lowest in t5, which was significantly different from t2 but not from t0. Ki-67 positive cells in the stroma varied between groups with c0c1 = 0.2 ± 0.45, t0 = 8 ± 12, t2 = 18 ± 12 and t5 = 10 ±7 positive cells/section. More Ki-67 positive cells were found in t2 compared to t5. This was not significantly different from t0. Caspase-3 and α-SMA expression were similar in all treatment groups.Canine corneas treated with CAP showed similar corneal wound healing compared to untreated corneas ex vivo. A 5-minute CAP application results in a lower perilimbal epithelial cell density and fewer Ki67 positive stromal cells compared to the 2-minute treatment.