Testicular weight and DNA content were markedly reduced (63 and 69%) in weanling Long-Evans rat pups rendered hypothyroid from birth by administration of propylthiouracil (PTU), a reversible goitrogen. These growth deficits worsened to > 80% by continuing hypothyroidism beyond weaning, to days 50 and 90. Recovery of thyroid function, brought about by discontinuing PTU at weaning, resulted in a paradoxical stimulation of testis growth, amounting to increased weight (40%), DNA content (60%) and size by 90 days, compared to age-matched controls. In the 25-day or older hypothyroid rats, testicular structure was immature and spermatogenesis markedly delayed, as evident by closed lumen and significantly reduced diameter of seminiferous tubules (38%), thickness of germinal layer (70%), and number of primary spermatocytes (86%), compared to control. Hypothyroidism did not alter the number of tubules per testis cross section. In the 90-day recovery rats, numbers of seminiferous tubules were unchanged but tubular diameter was significantly (20%) larger than in controls and spermatogenesis appeared very active as indicated by significantly increased germinal layer thickness (22%) and total number and density of primary spermatocytes (55% and 40%). The results show that although postnatal hypothyroidism is deleterious for testicular growth and spermatogenesis, recovery from this condition leads to enhanced seminiferous tubular growth and spermatogenesis.
Naegleria genus belongs to the flagellate free-living amoebae, which is ubiquitous in the environment (De Jonckheere, 2011). They have been found in various water resources (rivers, lakes and hot springs) and soil environments all around the world (De Jonckheere, 2011). Naegleria genus is classified in the Vahlkampfiidae family consisting of 47 species. There are three morphological forms to its life cycle: feeding trophozoite stage, transitional flagellate stage and dormant cyst stage (Siddiqui, Ali, Cope, & Khan, 2016). Naegleria fowleri is the only pathogen species of the genus Naegleria that is commonly known as brain-eating amoebae. It can cause a rare and devastating
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