Influence of maternal hypothyroidism on the postnatal development of rat testes as detected by morphometric and lectin histochemistry analysis

Abstract

Thyroid disorders are currently among the most widespread endocrine pathologies, influencing multiple organs, testes among others. However, the impact of maternal hypothyroidism on postnatal development of male reproductive system including its glycome currently remains obscure. Aim. By means of morphometric and lectin histochemistry analysis to investigate the influence of maternal hypothyroidism on postnatal morphogenesis of rat progeny testes. Material and Methods. Experimental hypothyroidism was induced in 15 female Wistar rats by supplementation of their daily food allowance with 5 mg/kg of mercazolil during 14 days prior to fertilization and during whole gestational period. Testes of their progeny on prenatal day 20th, postnatal days 1st, 20th, 40th and 120th were excised, fixed in Bouin's fluid, embedded in paraffin and subjected to morphometric and lectin histochemistry investigation. The obtained data was compared with the same parameters of progeny from control group rats. Results and Discussion. Maternal hypothyroidism in prenatal day 20th rats was associated with decreased size and enhanced count of Sertoli cells within the seminiferous cords; decreased amount of interstitial connective tissue combined with significant elevation of Leydig cells count and reduced lectin binding to all testicular components. On postnatal day 1st it was detected the increased Leydig cells content, though less prominent in comparison with prenatal period. On postnatal day 20th size of seminiferous tubules of hypothyroid rats progeny strongly exceeded control parameters due to the increased spermatogenic cells proliferation rate. On postnatal day 40th seminiferous tubules of experimental group rats contained large conglomerates of degenerating and apoptotic spermatogenic cells. In the adult rats, the decreased size of seminiferous tubules coincided with the increased spermatogenic index and content of Leydig cells. The latter were selectively labeled with PSA, GNA and CCRA, mast cells - with WGA, early acrosomes - with SBA, cap stage and wedged acrosomes - with PNA and SNA lectins. Conclusions. Maternal hypothyroidism has significant impact on postnatal morphogenesis of the rat testes. Differences in lectin binding to tissue samples of control and experimental rat testes were most significant in prenatal animals with certain levelling until adulthood, while morphometric indices were clearly distinct in all investigated progeny groups. Documented selective lectin labeling of Leydig cells with lectins PSA, GNA and CCRA, of mast cells with WGA, as well as different stages of acrosomal maturation with SBA, PNA and SNA can be recommended for further morphometric investigations.

Keywords

• experimental hypothyroidism, rat testes postnatal morphogenesis, morphometry, lectin histochemistry