General Morphological Observations
Testis weights were reduced by 22% in T3-implanted rats compared with normal controls, but weights were fully maintained in T24-implanted rats (Fig. 1A). In bilaterally cryptorchid rats, testis weights declined by 67% compared with those in controls, but neither the T3- nor T24-implants had any additional effect. These weight changes were attributable to a loss of some late-stage spermatogenic cells in the T3-implanted testes and complete regression of the seminiferous epithelium in abdominal testes (data not shown).
After perfusion-fixation, testis weights were increased only slightly (approximately 5-7%) over the corresponding nonperfused testis weights, with the exception of the nonimplanted abdominal testes group weights, which were increased by 12% (Fig. 1B). These data were consistent with the experimental observation of significant swelling of the flaccid abdominal testes during perfusion.
Total IF volume was not affected by T-implants in scrotal testes (Fig. 1C). However, cryptorchidism caused a 3fold increase in volume that was at least partially prevented by both the T3- and T24-implants. This result suggested that the greater increase in testis weight following perfusion of the nonimplanted abdominal testes may have been related to an increased capacity of the testis volume to expand under perfusion pressure. Since the expanded interstitial space was lost during subsequent processing and sectioning of the abdominal testis, all following data are based on calculations for the nonperfused testis weights. However, all data analysis was performed using both unperfused and perfused testis weights, and no substantial differences in results were observed.
FIG. 1. Testis weight and IF volume data for adult rats with scrotal or abdominal testes without implants (C, Co), with T3-implants, or with T24 implants. A) Nonperfused testis weights. B) Increase in testis weight (%) following perfusion fixation, as calculated from the difference between the nonperfused and perfused testis collected from each animal. C) IF volumes. Values with same letter subscript are not significantly different (p > 0.05).