VALIDATION OF FLOW-CYTOMETRY ANALYSIS IN THE OBJECTIVE ASSESSMENT OF SPERMATOGENESIS - COMPARISON TO THE QUANTITATIVE TESTICULAR BIOPSY

Objective determination of spermatogenesis has been accomplished by qu antitative testicular biopsy, which, although laborious, has served as the standard for spermatogenic assessment. Aspiration deoxyribonuclei c acid (DNA) flow cytometry of the testis, however, has simplified thi s determination, and has correlated with indirect hormonal parameters of spermatogenesis and qualitative observations of the seminiferous ep ithelium. Nevertheless, this important modality has yet to be validate d against quantitative micrometry of the testis. To determine this cor relation we submitted 29 incisional testicular biopsies for simultaneo us quantitative analysis and DNA flow cytometry. Micrometric parameter s included the mean tubular wall thickness, and the mean tubular conce ntration of late spermatids and Sertoli cells. The percentage of haplo id, diploid and tetraploid cells was determined for each patient. For the entire patient population a statistically significant correlation was observed between the percentage of haploid cells and the tubular c oncentration of late spermatids (r = 0.784, p < 0.0005) as well as the mean tubular spermatid-to-Sertoli cell ratio (r = 0.824, p < 0.0005). A similar correlation was noted for various etiological subsets of pa tients: spinal cord injury (r = 0.809, p < 0.002), genital tract obstr uction (r = 0.705, p < 0.02) and miscellaneous diagnoses (r = 0.828, p < 0.02). For the group with testicular failure quantitative micrometr y and flow cytometry demonstrated severe impairment in all patients al though a statistically significant correlation could not be shown beca use of the small range of values. DNA flow cytometry analysis correlat es strongly with the current standard of quantitative spermatogenic as sessment and, therefore, it may be validated as a simplified and highl y objective method of determining spermatogenesis.