title: The effect of methimazole-induced postnatal hypothyroidism on the retinal maturation and on the Sirtuin 2 level.
abstract: OBJECTIVE
  To investigate the effect of methimazole-induced postnatal hypothyroidism on the retinal maturation and to study Sirtuin 2 (SIRT2) level in the hypothyroidic rat retina.
  
  
  METHODS
  Twenty newborn Wistar albino rat pups were used in this prospective, randomized study. Wistar albino rats, weight 250-300 g, were impregnated (without addition of any drug) and were fed normally. Rat pups were randomly divided into two groups and were fed with breast milk. After weaning till they were 90 days of age, rat pups received the same water as their lactating mothers drank. Group 1 (methimazole (MMI)-induced hypothyroidy group), rats were given MMI-water, whereas, in Group 2, normal tap water. When the pups were 90 days of age, 20 rat pups were decapitated and the eyes were isolated. Eyes were investigated using histological, histomorphometric and immunohistochemistrical techniques.
  
  
  RESULTS
  No histological difference was seen between the groups stained with hematoxylin and eosin. In both groups the retinal layer structures and cells were observed as normal. The examples in the groups had a normal distribution for retinal thickness (pixel) measure. The mean value (mean ± std. deviation) was 554.7 ± 228.4 in the control group and 494.7 ± 129.4 in the hypothyroidy group. There was no significance between the groups in terms of retinal thickness (p = 0.231). However, immunohistochemistry revealed that SIRT2 was weaker stained in the ganglion cell layer and visual cell layer in the hypothyroidy group compared to the control group.
  
  
  CONCLUSIONS
  Postnatal hypothyroidism altered the retinal cytoarchitecture and layering which are regulated by thyroid hormones (THs) during retinal maturation in the postnatal period. THs may act by the induction of the SIRT family proteins or through their receptors. Postnatal screenings for THs levels are very important to provide normal retinal development.
authors.affiliation: a Department of Ophthalmology .
authors.forename: Tolga
authors.initials: T
authors.lastname: Kocaturk
authors.affiliation: b Department of Histology , and.
authors.forename: Kemal
authors.initials: K
authors.lastname: Ergin
authors.affiliation: c Department of Physiology , Adnan Menderes University Faculty of Medicine , Aydin , Turkey.
authors.forename: Gokhan
authors.initials: G
authors.lastname: Cesur
authors.affiliation: a Department of Ophthalmology .
authors.forename: Gokhan Evren
authors.initials: GE
authors.lastname: Evlicoglu
authors.affiliation: a Department of Ophthalmology .
authors.forename: Harun
authors.initials: H
authors.lastname: Cakmak
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D013956:Antithyroid Agents; D005260:Female; D007037:Hypothyroidism / Q000139:chemically induced / Q000378:metabolism*; D008713:Methimazole; D017208:Rats, Wistar; D012160:Retina / Q000033:anatomy & histology / Q000187:drug effects* / Q000378:metabolism; D056565:Sirtuin 2 / Q000378:metabolism*
chemical_list: D013956:Antithyroid Agents; C097475:Sirt2 protein, rat; D008713:Methimazole; D056565:Sirtuin 2
keywords: Methimazole; Sirtuin 2; postnatal hypothyroidism; retinal maturation