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.

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.

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.