IFIBIO HOUSSAY   25014
INSTITUTO DE FISIOLOGIA Y BIOFISICA BERNARDO HOUSSAY
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Degenerative and angiogenic effects of hyperthyroidism on the adult zebrafish retina
Autor/es:
BEJARANO CA; FAILLACE MP
Lugar:
Buenos Aires
Reunión:
Congreso; Reunión Conjunta de Sociedades de BioCiencias 2017; 2017
Institución organizadora:
SAIC, SAFIS, SAFE, SAIB, SAA, SAI, SAB, SAB, SAH, SAP
Resumen:
Alterationsof the neuro-glio-vascular unit underlie different pathologies of the CNS,including retina pathologies. Adult zebrafish (ZF) are able to regeneratetissues and organs being a suitable model to study the regulation of cell genesisand differentiation.We examinedthe effect of hyperthyroidism induced by exposure to elevated levels of T4 on repairingthe neuro-glio-vascular circuit during retina regeneration in the ZF.Retinas ofa group of ZF were injured with an intravitreal injection of ouabain whereas controlgroups were injected with saline. Then, the animals were separated into fourgroups: 2 groups  (injured and saline)were treated with T4 (300 μg /L)  andother two groups (injured and saline) were treated  with vehicle (0.1 M NaOH) in the tank water upto 25 days after injury (dpi). Euthanasia was done and retina sections wereobtained at 25 dpi. Double immunofluorescence was performed to detect differentcell populations and vascularization in the retinal tissue. mRNA levels of Thyroidhormone receptors (TRs), VEGF receptors (VEGFRs) and cell-type markers in theretina were detected by quantitative RT-PCR.Retinaneovascularization was observed in the groups exposed to elevated levels of T4either injured or not injured. Analysis of virtually all cell populations and theirsynaptic connections showed a significant decrease in cell number as well as inthe dimension of synaptic layers in lesioned ZF. mRNA relative expression ofTRs and VEGFRs showed significant changes depending on the receptor type.  mRNAs of cell markers correlated with the observedmorphological changes. Inconclusion, an exacerbation of the TH signaling system induces severeinhibition of retina cell regeneration and tissue growth alterations. Moreover,high T4 levels induced retina neovascularization. The changes observed in both injuredand T4-treated retinas in the long term are compatible with processes describedin neurodegenerative and neovascularizing retinopathies.