QUANTIFICATION OF SPERMATOGENESIS BY DUAL-PARAMETER FLOW-CYTOMETRY

Objective: To investigate the usefulness of dual-parameter flow cytometry of testicular fine-needle aspirates for the quantification of spermatogenesis. Immunofluorescence staining for vimentin was introduced to discriminate vimentin-negative germ cells from vimentin-positive stromal cells. The results of flow cytometry were compared with testicular morphology and immunohistochemistry in cases of regular and disturbed germ cell maturation. Design: Testicular fine-needle aspiration and surgical biopsy were performed in 50 autopsy cases. The fine-needle aspirates were double stained for the intermediate filament vimentin by indirect immunofluorescence and DNA propidium iodide and analyzed by flow cytometry. Surgical biopsies were examined by light microscopy. The distribution of vimentin-positive cells was evaluated by immunohistochemistry. Results: A comparison of morphology and flow cytometric analysis yielded characteristic quantitative distribution patterns of the different germ cell and somatic cell populations in regular and disturbed spermatogenesis. All three ploidy compartments of the germ epithelium correlated with high statistical significance with the respective histologic diagnoses. Moreover, a marked quantitative increase of stromal cells could be demonstrated in spermatogenetic disorders. Conclusions: The simultaneous analysis of the cellular DNA content and the intermediate filament vimentin by flow cytometry enables a detailed investigation of spermatogenetic disorders. Quantitative changes of the relationships between germ cells and somatic cells can be selectively investigated.