QUANTITATIVE-ANALYSIS OF SMOOTH-MUSCLE FIBERS IN CORPUS CAVERNOSUM OFHUMAN FETUSES

Purpose: Quantify objectively the normative distribution and the perce ntage of smooth muscle fibers in the corpus cavernosum of human fetuse s with 24 weeks post-conception (WPC) of gestational age. Material and Methods: We studied 7 penises taken from 7 fresh human fetuses. We an alyzed 5 randomized sections from each penis and in every section we a nalyzed 3 fields, totaling 15 fields per penis and 105 fields for the final results. Immunohistological staining for the smooth muscle fiber s was used to accentuate the differences between the intracavernous st ructures (smooth muscle fibers and collagen fibers). The fields studie d were digitized with a final magnification of 450X and a computerized analysis of the smooth muscle fibers was performed with image analyze r software. The percentage of smooth muscle fibers per standard square area was estimated and the mean value was used for each penis. Result s: The distribution of smooth muscle fibers in the corpus cavernosum o f human fetuses with 24 WPC of gestational age ranged from 17.52% to 2 7.76% of the total area. The mean value was 22.72% and the standard de viation was 3.56. Conclusions: Our results show that the percentage of smooth muscle cells in corpus cavernosum of human fetuses with 24 WPC of gestational age is significantly smaller when compared with the da ta available for adult cadavers.