Microcirculatory, micro-rheological, metabolic and histomorphological investigation of experimental mesoblastic nephroma in rats treated with Vincristine.

The development of malignant tumors and their abnormal vasculature can lead to severe changes in tissue perfusion. In this pilot study, we aimed to investigate changes in renal microcirculation and parenchymal abnormalities without treatment and after Vincristine treatment in a rat model of mesenchymal mesoblastic nephroma (Ne/De) tumor cell implantation of rat origin, which closely resembles Wilms' tumor. On the 1st, 4th, and 9th post-operative days, blood samples were collected to test for hematological parameters, erythrocyte deformability, and aggregation. In the Vincristine-treated group the animals received 0.25 mg/kg Vincristine on four occasions. We monitored renal microcirculation, obtained positron emission tomography imaging, and measured the blood flow of the abdominal aorta and the bilateral renal artery and vein. The kidneys were removed for histological analysis at the end of experiment. Leukocyte and platelet count gradually decreased in the Vincristine-treated group during the follow-up period. A significant increase in erythrocyte aggregation was observed after tumor implantation, while this increase was much smaller with Vincristine administration. Erythrocyte deformability deteriorated significantly by day 9th after tumor implantation. In the Tumor-implanted group, we observed structural characteristics of the tumor tissue and a heterogeneous blood flow pattern compared to the contralateral healthy kidney. The tumor growth inhibitory effect of Vincristine was observed. Malignant renal tumors caused significant deterioration and heterogeneity in microcirculation, which may be partly a consequence of abnormal vasculature and partly of deteriorating micro-rheology. The model is similar to Wilms tumor and is suitable for investigating rapid tumorigenesis, tumor vasculature, and therapeutical agents.