갑상선기능저하증 흰쥐 뇌의 StarD6 출생 후 발달

Abstract

Steroidogenic acute regulatory protein (StAR)-related lipid transfer (START) domain consists of ~ 210 residues and is implicated in intracellular lipid transport, lipid metabolism, and modulation of signaling events. StarD6, one of 15 START proteins, has recently been reported in the brain, which responses after excitotoxic injury and might have different roles during development. Therefore, I hypothesized that StarD6 might act on the critical period of maturation in developing rat brain. To investigate this hypothesis the postnatal development of StarD6 immunoreactivities in the rat brain was examined and compared with that of hypothyroid rats since thyroid hormone is essential for brain development. Pregnant Sprague-Dawley rats were administered 6-propyl-2-thiouracil (0.05% wt/volume, p.o.) or water from gestation day 11 to postnatal day (P) 28. Total body weights were checked every week. Brains were removed on scheduled time and examined by immunohistochemistry. Postnatal development of StarD6 immunoreactivities in the rat brain can be summarized as follows; 1) an inside-out gradient of radial emergence in the cerebral cortex, 2) an interspecies uniformity of cerebellar cortex, 3) the area-specific maturation from CA3 to CA1, and 4) an adult-like distribution at P21. Hypothyroid offsprings displayed evidence of growth retardation and alteration of behavior compared with those of normal rats. StarD6 immunoreactivities of hypothyroid rats were delayed and decreased maturation in brain region, and did not reach an adult-like distribution even at P28. These data demonstrated that StarD6 might affect in the maturation of region-specific principal cells, which is affected from P14 by perinatal hypothyroidism on the basis of StarD6 immunolocalization. The altered expression of StarD6 might be related with compromised functions in hypothyroid rats.