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Evaluation of Food and Food Contaminants
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 5, 2017
William J. Rea, Kalpana D. Patel
In general, phagocytosis of spermatozoa by the epithelial cells of the cauda epididymis is very low. It has previously been suggested that damaged spermatozoal cells can be phagocytosed,471 but the interpretation of these data has been challenged.472 Furthermore, if TCDD treatment did stimulate phagocytosis to the extent that sperm counts decreased by almost 40%, one would expect this to be obvious when examining the morphology of the epididymis. This does not appear to be the case, given the lack of reference of such an effect. A second possibility is that the blood–epididymal barrier is compromised, resulting in activation of the immune system, thus allowing macrophages to readily enter the lumen of the epididymis and attack maturing spermatozoa.473 Although this may explain the loss of epididymal spermatozoa, we found no reports of large numbers of macrophages within the epididymal lumen. A more likely possibility is that spermatozoa transit time is altered, resulting in fewer spermatozoa stored in the cauda epididymis. The epididymis is a long, open-ended, and highly convoluted tubule.474 Spermatozoa are stored in the cauda epididymis, but the retention of spermatozoa in this region is not well understood. Perhaps the best explanation is related to the length and high degree of convolution in this region of the epididymis. Changes in the convoluted nature of the cauda or the length of the cauda could directly affect the quantity of spermatozoa retained in the epididymis. Antiandrogenic compounds such as phthalates reportedly alter epididymal development and coiling of the epididymal tubule,475 and flutamide significantly reduces the size of the cauda epididymis476; however, whether the length of the epididymal tubule is also reduced is unknown. Wilker et al.459 reported that neonatal administration of TCDD resulted in a loss of epididymal segmentation, although they did not report whether this is associated with alterations in the cauda. Epididymal sperm transit time may also be affected by changes in the composition of epididymal fluid. Water is reabsorbed from the seminal fluid in the efferent ducts between the testis and epididymis,477 a process regulated by estradiol and mediated by estrogen receptor-α (ERα).478 TCDD is known to block estrogen action by activating the AhR, which has been shown to partly bind to the estrogen response element of estrogen-dependent genes.479 In the epididymis, after treatment with antiestrogens, or in ERα-knockout mice, there is retention of water in the seminal fluid,478 which is associated with a decrease in cauda epididymal sperm counts.480 Less concentrated sperm would exhibit faster transit time, particularly in the cauda epididymis, because fluid pressure in the epididymal lumen would likely be increased. Thus, the effect of dioxin and dioxin-like chemicals on epididymal structure and function requires further study.
Maternal bisphenol A exposure disrupts spermatogenesis in adult rat offspring
Published in Journal of Toxicology and Environmental Health, Part A, 2019
Patricia De Campos, Isabela M. Oliveira, Janaina Sena de Souza, Rodrigo Rodrigues Da Conceição, Gisele Giannocco, Maria I Chiamolera, Magnus R.Dias-Da Silva, Marco A. Romano, Renata Marino Romano
Immature sperm that arrive at the initial segment of the epididymis from efferent ducts of the testes are immobile and not able to fertilize (Robaire and Hinton 2015). These characteristics are acquired after the sperm are influenced by the complex epididymal milieu responsible for the maturational events (Robaire and Hinton 2015). Sperm transit across the epididymis segments is essential for maturation and there is a minimum time for spermatozoa to transit in the epididymis segments. The maturation process is compromised if sperm transit too quickly through epididymis (Robaire and Hinton 2015). In contrast, higher sperm transit time after blocking the adrenergic activity with guanethidine did not affect sperm motility (Kempinas et al. 1998) and the ability to fertilize (Fernandez et al. 2008). Martin-Deleon, Shaver, and Gammal (1973) reported that spermatozoa that were aged in the male reproductive tract of rabbits induced a 10-fold higher incidence of chromosomal abnormalities in the resulting blastocysts than did their fresh counterparts. Since sperm is stored in the epididymis cauda, the sperm waits to be released by ejaculation and the time is dependent upon ejaculation frequency (Robaire and Hinton 2015). However, Aitken (2018) questioned whether small changes in testicular and epididymal environments may be responsible for disorders in the offspring that were transmitted by spermatozoa. Perinatal BPA exposure increased sperm reserves by approximately 40%, and sperm transit time in cauda epididymis by approximately 50% in both BPA treatment groups. The effect on sperm of increased time of permanence of spermatozoa in all epididymis segments, not only in cauda, still needs to be more comprehensively investigated with additional parameters, such as sperm functionality and chromosomal integrity. In this study, sperm abnormalities may be influenced by longer time spent in all epididymis segments.