Diagnostic Approach to Nephrotoxicosis with Vitamin K3 in Draft Horses Based on iNOS and Selective Urinary Variables

A total of 17 draft horses were used in this study as two groups; vitamin K3 exposed group includes 7 draft horses administered vitamin K3 orally (4 field cases and 3 experimental cases).10 apparently healthy draft horses used as a control group. The four field cases showed signs of nephrotoxicosis 12-24 h following oral supplementation with double doses of vitamin K3(10mg/kg b.wt) with a one-day interval. The three experimental cases were administered vitamin K3 simulator to the field cases. The diagnosis was based on owner complaint, case history, duration of clinical signs, physical and clinical examination as well as ultra sonographical imaging, clinicopathological and histopathological findings. Results revealed that most of the vitamin K3 exposed group showed signs of renal colic, poor performance, depression, stranguria and oliguria. Laboratory findings showed hematuria, proteinuria, azotemia and hyperal -buminemia. Additionally, elevated urinary malondial dehyde, nitric oxide, gamma-glutamyl transferase, renal iNOS activities over baseline and declining in CrCl were observed. Histopathologically, proliferative glomerulonephritis and globular eosinophilic proteinisuos casts in the majority of the intact renal tubules were detected. In conclusion, oral vitamin K3 administration in equine resulted in oxidative and nitrosative renal damage and inducing acute renal injury, via increasing nitric oxide level and lowering the activity of nitric oxide synthase enzyme in renal tissue.