Splenic hemangiosarcoma in a young sprague-dawley rat.

The present report describes a rare case of spontaneous hemangiosarcoma in a nine-week-old male Sprague-Dawley rat. At necropsy, multiple white nodules of various sizes were observed on and within the enlarged spleen and liver and were histopathologically determined to be composed of spindle- to oval-shaped cells that showed invasive growth without encapsulation and were arranged solidly but partially in whorls or faint alveolar patterns with vascular-like spaces containing small clefts or erythrocytes in the tumor mass. Immunohistochemical analysis revealed that most of the tumor cells were strongly positive for vimentin, von Willebrand factor (vWF) and CD34 but negative for podoplanin. In addition, electron microscopic examination revealed the presence of Weibel-Palade bodies in the cytoplasm of the tumor cells. Based on these findings, this case was diagnosed as a hemangiosarcoma. The splenic masses were larger than the hepatic ones, with tumor cells mainly observed at periportal regions with tumor embolism in the liver, suggesting that primary hemangiosarcoma initially developed in the spleen before metastasizing.

Comparison of the course of biomarker changes and kidney injury in a rat model of drug-induced acute kidney injury.

OBJECTIVE: To aid in evaluating the performance of biomarkers, we measured kidney injury biomarkers in rat models of drug-induced acute kidney injury. METHODS AND RESULTS: Rats were treated with site-specific nephrotoxins, puromycin, gentamicin, cisplatin, or 2-bromoethylamine. Fifteen biomarkers (ß-2-microglobulin, calbindin, clusterin, cystatin-C, KIM-1, GST-α, GST-µ, NGAL, osteopontin, EGF, TIMP-1, VEGF, albumin, RPA-1, and urinary total protein) were examined in comparison with BUN, serum creatinine, and NAG. Some biomarkers, which were different depending in each nephrotoxin, showed ability to detect the prodromal stage of drug-induced kidney injury. Characteristic changing patterns of biomarkers were also found depending on the specific lesion site in the kidney. CONCLUSION: These data suggested that establishment of a suitable biomarker panel would facilitate detection of site-specific kidney injury with high sensitivity.

Progression of glomerulonephritis to end-stage kidney disease in a cat with nephrotic syndrome.

A percutaneous renal biopsy was performed on a 3-year-old female Japanese domestic cat with pleural effusion, mild azotemia, hypoalbuminemia, hypercholesterolemia, and proteinuria. Glomerular lesions included mild diffuse hypercellularity and numerous capsular adhesions with segmental sclerosis/hyalinosis of glomerular tufts. Electron microscopy revealed many subendothelial dense deposits with characteristic outer protrusion of glomerular basement membrane. Diffuse and global granular deposits of IgG and C3 were detected along the capillary walls. Tubulo-interstitial changes were mild at the time of biopsy, but progression of the disease was predicted because of the many capsular adhesions of the glomerular tufts. The cat was fed a prescription diet without any other specific or symptomatic therapy after renal biopsy, and died 43 weeks after the biopsy. At necropsy, extensive tubulo-interstitial fibrosis and mononuclear cell infiltration had developed throughout the cortex and outer medulla, and most glomeruli had extensive global sclerosis or obsolescence with less prominent depositions of IgG and C3.

A Case of Spontaneous Malignant Hibernoma in a Crl:CD(SD)IGS Rat.

A firm, tan, well-circumscribed mass that measured 25 × 30 × 35 mm was observed in the thoracic cavity of a 53-week-old male Crl:CD(SD) IGS rat. Histologically, the mass was encapsulated by fibrous tissue and contained fibrovascular septae. Tumor cells were compactly arranged, and most were oval to polygonal in shape with multivacuolated cytoplasm and a centrally located nucleus. In some parts of the tumor, marked cellular atypia and frequent mitoses were evident. Vacuoles in cytoplasm were positive for oil red O. The tumor cells were characterized ultrastructurally by abundant, round to oval mitochondria with transverse closely-packed cristae. Tumor cells were immunohistochemically positive for uncoupling protein 1 (UCP-1). Several thrombi and hemorrhagic or necrotic foci were also observed within the tumor mass. Vascular invasion of the tumor capsule was observed; however, invasion of surrounding tissues or metastases were not observed. Based on the pathology findings, this case was diagnosed as a malignant hibernoma.