The Effects Of Potassium Oxalate Injected Intravenously On Canine Kidney Function, Tissue Structure And Calcium Transport Proteins

Oxalic acid in the form of oxalate exists in almost all kinds of plants. It is a highly toxic compound, and the accumulation of oxalate in the body could induce various urological, including kidney stone, hyperoxaluria, acute kidneyinjury, etc. Statistics show that approximately85%of canine and feline submissions were classified as calcium oxalate or struvite in composition. From1981to2008, there was a significant decrease in the prevalence of struvite, but a significant increase in the prevalence of calcium oxalate during the period.In order to study changes of the renal function and histopathology in dogs suffered calcium oxalate nephrocalcinosis. Ten beagle dogs were randomly divided into control and treatment groups(n=5). According to the body weight,0.5mol/L potassium oxalate(treatment group)and0.9%NaCl solution(control group)were injected into canine cephalic vein, TID, successively for7days. The clinical manifestations of canine were recorded, and the serum was collected daily for biochemical tests during the period of experiment. Initial ultrasound examinations were performed in all dogs. After the last injection, a small amount of kidney tissues were surgically collected from each dog. The renal tissues pathologic and ultrastructural alteration was checked by tissue sections. The protein and gene expression level of TRPV5、NCX1、Calbindin-D28k were checked by fluorescent quantitation PCR and immunohistochemistry.Results:(1) The results showed that the canine kidney with petechial hemorrhage and swelling can be observed in treatment group. After the tissue sections stained by Pizzolato’s method, there are many black plaque blocked in lumen. X ray electron probe showed the components of crystals were C, O, Ca elements. Diffuse cortical increased in echogenicity were detected. Canine serum biochemical indexes in treatment group were significantly higher than that in control group(P<0.05).(2) Glomerulus was in different degrees of damage, renal interstitial inflammatory cells accumulated. Protein casts can be observed in the cavities of renal and collecting tubules. SEM showed that there was no disruption in control group, but there were obvious foot processes derangement and effacement in treatment group, and mitochondria became swelling and crista fragmentation could be found in treatment group. The renal stroma was infiltrated with inflammatory cells after potassium oxalate injected intravenously. (3) The protein expression level of TRPV5、NCX1、Calbindin-D28k were in different degrees of decreased in treatment group. The gene expression level of TRPV5, NCX1, Calbindin-D28k were in different degrees of decreased in treatment group. NCX1, Calbindin-D28k mRNA expression level were decreased significantly (P<0.05)Conclusion:(1) Inducing CaOx nephrocalcinosis in dog by potassium oxalate injected intravenously brought less molestation.(2) Oxalic acid or calcium oxalate could damage the renal tissue structure, and cause acute kidney injury.(3) The protein and gene expression level of TRPV5、NCX1、Calbindin-D28k in treatment group were lower than that in control group.