tokens: In the ' conscious catheterized rat ' model , the glomerular filtration rate ( GFR ) was measured as the clearance of Cr ( EDTA ). The morphological analysis of the kidneys included a semi - quantitative scoring system analysing the degree of striped fibrosis , subcapsular fibrosis and the number of basophilic tubules , plus an additional stereological analysis of the total grade of fibrosis in the cortex stained with Sirius Red .