Effects of obstruction of the flow of seminiferous tubule fluid on the germinal epithelium in the rat.

Blocking the lumen of a single seminiferous tubule by introducing a plug of non-toxic latex produced a lesion in that tubule, but not in immediately adjacent tubules. The lesion extended for up to 50 mm from the end of the latex. Nearest to the block the tubule was completely aspermatogenic; further along the tubule, the lesion was less severe, involving disorganization and reduction in germ cell numbers, with the cells showing vacuolation, pycnosis and karyolysis. Binucleate and giant cells were common, and cells were often exfoliated into the lumen. The lesion tended to increase in length with longer times after introduction of the plug, but there appeared to be no preferential involvement of the shorter segment of the tubule between the block and the rete. The transition from damaged to healthy tubule was abrupt.