Effect of efferent duct ligation on the function of the blood-testis barrier in rats

The function of the blood-testis barrier has been assessed from the ratio o f the Cr-EDTA space in the parenchyma to the measured interstitial volume i n the testes of rats at various times after unilateral ligation of the effe rent ducts. The barrier remained effective during the phase of fluid accumu lation and testicular mass gain, which was linear for at least 24 h, but th e testis mass began to decrease between 32 and 40 h after efferent duct lig ation, and the Cr-EDTA space at 40 and 48 h after efferent duct ligation ex ceeded the volume of the interstitial tissue. This finding indicated that, at these times, the barrier to Cr-EDTA, which is normally excluded from the tubules, had broken down and the marker was entering the tubules. Thereaft er, the Cr-EDTA space decreased again to be less than the interstitial tiss ue volume, indicating a restoration of the barrier function, although degen eration of the seminiferous epithelium continued to become more obvious. Th e present study is the first report of a reversible breakdown of the barrie r, but the relevance of the breakdown to the effects on spermatogenesis req uires further study.