Retention, Bacterial Adhesion, and Biofilm Formation between Anionic and Zwitterionic Bandage Contact Lenses in Healthy Dogs: A Pilot Study.

This study aimed to compare the in vitro and in vivo retention, bacterial adhesion, and biofilm formation between anionic and zwitterionic bandage contact lenses (BCLs) in healthy canines. BCL retention and tolerance were evaluated in 10 healthy canines via a single-masked, crossover study for 7 days. To compare in vitro bacterial adhesion and biofilm formation, four Staphylococcus strains were incubated with the BCLs at 37 °C for 2 or 24 h, and the bacterial colony forming units (CFUs) adhering to the BCLs were counted. Next, to compare in vivo bacterial adhesion, the CFUs of bacteria adhering to the BCLs worn by canines for 24 h were counted. Anionic lenses significantly retained and reduced in vitro bacterial adhesion than in the zwitterionic lenses. However, the amount of in vitro biofilm formation was more likely to be higher on anionic lenses than on zwitterionic lenses. In vivo bacterial adhesion was not significantly different between the two types of BCLs. Nevertheless, both BCLs were well-tolerated by the canines; thus, their short-term use in dogs can be recommended as safe.

Magnesium Hydroxide Nanoparticles Improve the Ocular Hypotensive Effect of Twice Daily Topical Timolol Maleate in Healthy Dogs.

Timolol maleate (TM), a beta-adrenergic receptor antagonist, is widely used for canine antiglaucoma eye drops; however, its bioavailability is <5%. Our previous study revealed that magnesium hydroxide nanoparticles (nMH) have potency in improving the bioavailability of fixed-combined TM in rodent models. This study aimed to investigate whether the fixed combination with nMH improves the ocular hypotensive effect of TM and affects pupil size (PS), heart rate (HR), and mean arterial pressure (MAP) in clinically healthy dogs. Five clinically healthy dogs were administered topical saline, commercial 0.5% TM, and a 0.01% or 0.1% nMH-0.5% TM fixed combination (0.01% or 0.1% nMH-TM) twice daily in one eye for 7 days with at least a 28-day interval. The changes from baseline were calculated and were statistically analyzed for each drug. IOP was significantly reduced in both 0.01% and 0.1% nMH-TM-treated-dogs compared with saline- and TM-treated dogs. Meanwhile, 0.01% and 0.1% nMH did not exacerbate the side effects of TM. From these results, nMH improved the ocular hypotensive effect of TM without enhancing side effects. Topical nMH-TM is potentially more effective for canine ocular hypotensive eye drops than TM.

Primary cell culture of canine corneal endothelial cells.

OBJECTIVE: To establish a primary cell culture and clarify the characteristics of canine corneal endothelial cells in vitro. PROCEDURES: The eyes were enucleated from dogs that were euthanized for reasons unrelated to this study. Enucleated canine eyes were dissected, and the intact corneas were isolated from the globes. Using enzymes, the corneal endothelial cells were dispersed from the cornea. The obtained canine corneal endothelial cells were cultured in a cell culture dish. Cultured corneal endothelial cells were morphologically evaluated using phase-contrast microscopy. Immunohistochemical analysis of the cultured cells, particularly of the corneal endothelial cell marker, zonula occludens-1 (ZO-1), Na+ /K+ -ATPase, and vimentin, was performed to clarify whether the cultured cells were actually corneal endothelial cells. Furthermore, the post-passage morphology of cultured cells was evaluated. RESULTS: Canine primary cultured corneal endothelial cells showed morphologically small, cobblestone-like structures. The isolated cells had proliferative ability in vitro and demonstrated positive expression of the corneal endothelial cell markers, ZO-1, Na+ /K+ -ATPase, and vimentin. However, repeated passages resulted in larger cell sizes as assessed by phase-contrast microscopy. Repeated passages also resulted in lower cell density. CONCLUSIONS: This study demonstrated the successful culture of canine corneal endothelial cells. This might enhance the understanding of corneal endothelial cell characteristics in dogs.

Decellularization of canine kidney for three-dimensional organ regeneration.

BACKGROUND AND AIM: Kidney regeneration is required for dogs with end-stage renal failure. Decellularization is one of the bioengineering techniques, which involves the removal of all tissue cells and cellular components and conservation of the extracellular matrix (ECM). Studies in rats have shown that decellularized kidney has regenerative potential; however, there are no reports on renal decellularization in dogs. Here, we showed the decellularization of the canine kidney. MATERIALS AND METHODS: The renal artery of the cadaveric canine kidney was cannulated and the whole kidney was frozen at -80°C. After completely thawing, it was perfused with physiological saline and sodium dodecyl sulfate (0.5%, 6 h) through the cannulated renal artery to achieve decellularization. To assess the efficiency of the decellularization protocol, histological and immunohistochemical analysis of decellularized kidney was performed. RESULTS: The results of hematoxylin and eosin (H and E) staining revealed that the decellularized canine kidney had no apparent cellular components. In addition, 4',6-diamidino-2-phenylindole (DAPI) staining showed no visible nuclear components within the whole decellularized kidney. Therefore, both H and E and DAPI staining showed decellularization of the canine kidney. Our decellularization protocol also preserved the basement membrane of glomerulus, shown by periodic acid methenamine silver, periodic acid-Schiff, fibronectin, and collagen type IV stain. CONCLUSION: Our decellularization protocol could eliminate cellular components and remaining native ECM structures of canine kidney. These results could promote further research into canine kidney regeneration, which may be the first small step to regenerate the canine kidney waiting for renal transplantation.

Preventive effects of tyrosol, a natural phenolic compound, on anterior uveitis induced by anterior chamber paracentesis in healthy beagle dogs.

We investigated the effects of tyrosol (Tyr) on anterior chamber paracentesis (ACP)-induced anterior uveitis in beagle dogs, as determined by protein and prostaglandin E2 (PGE2) concentrations in the aqueous humor (AH). Tyr at a dose of 100 or 200 mg/kg or 2.2 mg/kg of carprofen as a positive control was administered orally twice daily from 2.5 days before paracentesis. The initial ACP was performed in one eye of individual dogs and 0.5 ml AH was aspirated. The secondary AH was collected 60 min later. Pretreatment with 200 mg/kg of Tyr and carprofen significantly decreased aqueous protein and PGE2 concentrations compared to the control group. Overall, these findings suggested that Tyr was useful for the management of canine anterior uveitis.