Evaluation of developing rat testis by phosporus P-31 magnetic resonance spectroscopy and DNA flowcytometry

For the assessment of germ-cell maturation of the seminiferous tubules, DNA flowcytometry is a rapid and sensitive method. Phosporus P-31 magnetic res onance spectroscopy (MRS) is a non-invasive alternative that demonstrates t he metabolic status of the testis, reflecting the type and relative proport ion of germ cells in the testis. This study was designed to evaluate the ut ility of P-31 MRS in reflecting the haploid-cell population of the testis a s measured by DNA flowcytometry. A single testicle was evaluated in male Wi star pre-pubertal rats at 30, 40, 50, and 60 days of age. In order to minim ize the contamination of signals from the contralateral testis, scrotum, an d tail, the technique was modified and the testis was evaluated ex-vivo wit h an intact blood supply. At 30 days of age the percentage of haploid cells was 43.6 +/- 1.8, and this increased to 72.7 +/- 1.4 at 60 days of age. Du ring this period, the testicular phosphomonoester/adenosine triphosphate (P M/ATP) ratio changed from 1.70 +/- 0.21 to 0.32 +/- 0.08. There was a signi ficant (P < 0.001) linear correlation between the proportion of haploid cel ls evaluated by DNA flowcytometry and the PM/ATP ratio evaluated by P-31 MR S. P-31 MRS is thus a reliable, noninvasive technique for accurately assess ing the status of the seminiferous epithelium.