Comparison of two stereological methods for quantitative renal morphology: A modified fractionator and modified Weibel-Gomez method

To determine the best method for quantitative analysis of renal structure, we compared two stereological techniques: the unbiased fractionator method and the model-based method described by Weibel-Gomez. Kidneys of 20 week old pregnant female Sprague Dawley rats were investigated. Using these two stereological techniques, the mean glomelular volume and the total glomerular number per kidney were determined in 16 kidneys of 8 rats. Both methods were used in a modified way to correct for variations in section thickness (fractionator) and to reduce the length of the measuring process (Weibel-Gomez), respectively. The mean glomerular volume was comparable in bath methods (Fractionator: 5.49 +/- 0.56 x 10(4) mm(3) Weibel-Gomez: 5.35 +/- 0.34 x 10(4) mm(3)). In contrast, using the Weibel-Gomez method (43774 +/- 2338), the total number of glomeruli per kidney was significantly higher than that obtained by the fractionator technique (39359 +/- 4250). The results as well as the time necessary for each method and the practicability of the techniques were compared. In our hands, apart from the respective advantages and disadvantages, the Weibel-Gomez technique is easier to perform and much more efficient than the probably more elegant fractionator method. The bias problem of the Weibel-Gomez method does not play an important role with respect to the most common biological problems.