Effects of di(2‐ethylhexyl) phthalate on gap and tight junction protein expression in the testis of prepubertal rats

Abstract

The aim of this study was to analyze whether di(2-ethylhexyl) phthalate (DEHP), a Sertoli and Leydig cell toxicant, is able to induce alterations in the expression of testicular gap and tight junction proteins. DEHP was administered by gavage (1 g/5 mL corn oil/kg body weight/day) to 25-day-old male Sprague-Dawley rats for 2 days (DEHP-27d) and control rats were treated with corn-oil vehicle for 2 days (C-27d); animals were killed 24 h after the last treatment. Testes of DEHP-27d rats showed different degrees of germ cell sloughing of seminiferous tubules (ST). No alterations of the blood testis barrier (BTB) by lanthanum tracer study were observed. ST of DEHP-27d rats showed a milder immunofluorescence and more restricted expression of connexin-43 (Cx43) in the adluminal and basal compartment compared to C-27d. In DEHP-27d rats, we found a discontinuous immunofluorescent (IF) pattern for zonula occludens (ZO-1), contrasting with the continuous IF profile observed in C-27d, and a delocalization of claudin-11. A decrease in Cx43 and ZO-1 and no changes in occludin expression were detected by Western blot in the testes of DEHP-27d rats. Results from 57-day-old rats treated with DEHP for 2 days and held for 30 days without treatment showed that the alterations in protein expression induced by DEHP are reversible. However, a delay of spermatogenesis compared to C-57d rats, occurred. Data demonstrated that DEHP does not impair BTB permeability but induces germ cell sloughing that might respond to a down regulation of Cx43 and ZO-1 that alters cell junction proteins.

Low-dose exposure to di-(2-ethylhexyl) phthalate (DEHP) increases susceptibility to testicular autoimmunity in mice

“…DEHP and MEHP induce germ cell sloughing that might be associated with downregulation of claudin-11, occludin, Cx43, and ZO-1 and changes in cell junction proteins of BTB [33]. In addition, exposure to MEHP decreases the inhibition of metalloproteinase-2 expression in testes tissue, which allows for matrix metalloproteinase 2 activation, leading to the remodeling of tight junctions between adjacent Sertoli cells [34]. On the other hand, many reports have also shown that while DEHP itself is not an immunogenic antigen, it can act as an adjuvant [4][5][6][7][8].…”

Blood–testis barrier and Sertoli cell function: lessons from SCCx43KO mice

“…In the latter study, a surge in the protein level of CLAUDIN11 was observed but its levels at the cell surface remained unchanged. In another study, the effects of the reproductive toxicant di(2-ethylhexyl) phthalate (DEHP) on testicular gap and tight junction protein expression were investigated in prepubertal rats (Sobarzo et al 2009). There it was shown that DEHP did not impair BTB permeability but induced GC sloughing that was accompanied by a downregulation of CX43 and ZO1 and alterations in other junctional proteins (Sobarzo et al 2009).…”

Testicular connexin 43, a precocious molecular target for the effect of environmental toxicants on male fertility

“…Similarly, postnatal toxicant exposure, through lactation, and prepubertal treatment of animals resulted in a reduction of testicular Cx43 expression, associated with germ cell sloughing and infertility. 117,140,142 Other authors reported that exposure of immature rats via lactation to a mixture of xenoestrogens (17-α-ethinyl estradiol, bisphenol A and alkyl phenols) exerted long-lasting deleterious effects on epididymal sperm concentration and motility and at the same time reduced Cx43 expression in the seminiferous epithelium, suggesting that the intercellular coordination of testicular function may be affected. 124 In addition to disrupt Cx43 gap junction functionality, recent studies demonstrated that a blockade of the channel coupling by BPA gives rise to signs of germ cell loss, resulting from Sertoli cell bloodtestis barrier impairment (BTB).…”