Early decrease of ionized calcium and static symmetric dimethylarginine concentration in a model of renal tubular necrosis in corn snakes (Pantherophis guttatus).

Abstract

To determine if plasma concentrations of symmetric dimethylarginine (SDMA), N-acetyl-beta-d-glucosaminidase (NAG), GGT, ALT, AST, lactate, total calcium, and ionized calcium (iCa) and the calcium:phosphorus ratio are clinically relevant biomarkers to detect early stages of tubular lesions in snakes. 6 adult corn snakes (Pantherophis guttatus). Corn snakes were administered 11 injections of gentamicin at 50 mg/kg, SC, q 24 h in an experimental model of induced tubular necrosis. Plasma biochemistry and blood gas analyses were performed at baseline and after the 3rd and 11th injections. Parameters were compared between time points using a paired Wilcoxon test. In 3 individuals, renal biopsies were collected at baseline before starting injections and at the 3rd and 11th injections, while renal tissue samples were procured after euthanasia in all individuals. Renal proximal and distal tubular necrosis and hepatic steatosis were present in all individuals at necropsy. Compared to baseline, decreased blood concentrations of lactate, ionized calcium, and total calcium and a decreased calcium:phosphorus ratio were noted. A significant decrease of lactate and ionized calcium was observed after 3 days. Conversely, no changes in SDMA, NAG, ALT, AST, GGT, and sodium were detected. Ionized calcium and lactate concentrations were the earliest parameters to decrease compared to baseline values in this experimental model. While SDMA is a sensitive indicator of renal disease in mammals, this biomarker did not increase in a model of induced acute tubular necrosis in corn snakes.