RESUMO
Prenatal glucocorticoids, commonly used in women at risk of preterm delivery, can predispose the newborn to disease in later life. Since male reproductive function is likely to reflect testis development during fetal life, we studied the effects of prenatal glucocorticoids on two key intra-testicular factors that play roles in cellular proliferation and differentiation, 3ß-hydroxysteroid dehydrogenase (3ß-HSD) and inhibin-α. Pregnant sheep (n=42) were treated with betamethasone (0.5 mg/kg) or saline (control) at 104, 111 and 118 days of gestation (DG). Testicular tissue was sampled from fetuses at 121 and 132DG, and from lambs at 45 and 90 postnatal days (PD). Within the betamethasone treated group, 3ß-HSD immunostaining area was greater at 121DG than at 90PD (P=0.04), but the intensity of immunostaining was higher at 90PD than at 121DG (P=0.04), 132DG (P=0.04) and 45PD (P=0.03). Control animals showed no changes in 3ß-HSD area or intensity of immunostaining. No significant differences were observed between treated and control animals in immunostaining area, but immunostaining was more intense in the treated group than in the control group at 90PD (P=0.03). For inhibin-α, the proportion of immunostaining area declined in treated offspring from 121DG to 45PD, in contrast to control values, but recovered fully by 90PD, concomitantly with the onset of spermatogenesis. In conclusion, prenatal betamethasone increased the postnatal testicular expression of inhibin-α but reduced the expression of 3ß-HSD. These effects could compromise androgen-mediated testicular development and therefore adult capacity for spermatogenesis.
Assuntos
17-Hidroxiesteroide Desidrogenases/metabolismo , Betametasona/farmacologia , Feto/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Inibinas/metabolismo , Testículo/metabolismo , Animais , Feminino , Feto/citologia , Feto/efeitos dos fármacos , Idade Gestacional , Técnicas Imunoenzimáticas , Masculino , Gravidez , Ovinos , Testículo/efeitos dos fármacos , Testículo/crescimento & desenvolvimentoRESUMO
Pre-natal glucocorticoids are used in women at risk of preterm delivery to induce foetal lung maturation. However, glucocorticoids can produce negative outcomes for other tissues such as the reproductive system. We therefore tested the effects of pre-natal betamethasone on testicular morphology and apoptotic protein immune expression during pre- and post-natal development. Pregnant ewes (n = 42) bearing singleton male foetuses were randomly allocated to receive intramuscular injections of saline or betamethasone (0. 5 mg/kg) at 104, 111 and 118 days of gestation (DG). Testes were collected at 121 and 132 DG, and at 45 and 90 post-natal days (PD) and subjected to morphometric analysis (volume densities of sex cords and interstitial tissues; sex cord diameter). Immunohistochemistry (% stained area) was used to assess active caspase-3, Bax, Bcl-2 and cell-cycle proteins (PCNA). Compared with control values, betamethasone treatment decreased sex cord diameter at 121 DG, 45 and 90 PD, and sex cord volume at 90 PD. Active caspase-3 was decreased by betamethasone at 121 DG and 90 PD, but Bax was increased in all betamethasone groups. Bcl-2 and PCNA decreased in the betamethasone groups at 121 DG and 45 PD, but increased at 132 DG and 90 PD. We conclude that high levels of pre-natally administered glucocorticoid reduce foetal testicular development, perhaps via changes in the balance between pro- and anti-apoptotic proteins and cell-cycle proteins. These outcomes could compromise the future spermatogenic potential of male offspring.
Assuntos
Apoptose/fisiologia , Betametasona/farmacologia , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Efeitos Tardios da Exposição Pré-Natal , Ovinos/crescimento & desenvolvimento , Testículo/efeitos dos fármacos , Animais , Betametasona/administração & dosagem , Feminino , Glucocorticoides/administração & dosagem , Glucocorticoides/farmacologia , Masculino , Gravidez , Testículo/crescimento & desenvolvimento , Testículo/metabolismoRESUMO
We tested the hypothesis that acute pre-natal exposure to high levels of synthetic glucocorticoid (betamethasone) would alter fetal testicular development through actions on gonadal glucocorticoid receptors (GRs). Pregnant Merino ewes bearing singleton male fetuses (n = 24) were allocated randomly among four equal groups to be injected intramuscularly with saline or betamethasone (0.5 mg/kg) either on day 109 of gestation or on both day 109 and day 116 of gestation. Fetal testes were collected at post-mortem, 5 days after each treatment. The volume of interstitial tissue and the volume, length and diameter of the sex cords were measured, and Sertoli cells and gonocytes were counted. For cord volume and interstitial tissue volume, control testes demonstrated maturational changes as fetal age advanced from 109 to 116 days of gestation. For that period, the single injection of betamethasone significantly reduced Leydig cell proliferation (P < 0.05), but had no effect on Sertoli cell numbers. Immunohistochemistry was used to localize GR and proliferating cell nuclear antigen in testicular cells. GR immunoexpression in Leydig cells was higher in fetuses exposed to betamethasone at 109 days of gestation than in control fetuses. Sertoli cells showed low levels of GR. It was concluded that, during mid-gestation, a brief period of glucocorticoid treatment could affect testicular development in male sheep fetuses. The mechanism probably involves direct effects on Leydig cells, as these cells express extra-GR in response to the treatment. Sertoli cells seem to produce less GR than Leydig cells, perhaps explaining their lack of response to betamethasone. These outcomes may have important implications for future fertility in male offspring.