Neuroprotective effect of melatonin on a neuroinflammation model of the visual pathway

ARANDA ML; GONZÁLEZ FLEITAS MF; DIEGUEZ HH; KELLER SARMIENTO MI; CHIANELLI MS; SANDE PH; DORFMAN D; ROSENSTEIN RE

Buenos Aires

Congreso; 2nd Congress of the Federation of Latin-American and Caribbean Societies for Neuroscience (FALAN); 2016

FALAN IBRO-LARC

S1P200. Neuroprotecti ve effect ofmelatonin on a neuroinflammation modelof the visual pathwa yMarcos L. Aranda1*, María F. González Fleitas1, HernànH. Dieguez1, Maria I. Keller Sarmiento1, Mónica S.Chianelli1, Pablo H. Sande1, Damián Dorfman1, RuthE. Rosenstein11 Centro de Estudios Farmacológicos y Botánicos, UBA /CONICET*marcos8877@gmail.comWe have developed a new experimental model of opticneuritis (ON) through the microinjection of bacteriallipopolysaccharide (LPS) into the optic nerve, whichreproduces central features of human ON. The aim of thiswork was to analyze the effect of melatonin (MEL) on theoptic nerve axoglial alterations induced by experimental ON.LPS was injected in one optic nerve from Wistar rats, whilethe contralateral optic nerve was injected with vehicle. Onegroup of animals received a pellet of MEL one day beforeLPS or vehicle injection, and another group was submittedto a sham procedure. In another set of experiments, thepellet of melatonin was implanted at 4 days post-injectionof LPS or vehicle. The effect of melatonin was analyzed at21 days post-injection in terms of: i) visual pathway function(visual evoked potentials (VEPs)), ii) anterograde transport,iii) pupil light reflex (PLR), iv) microglia/macrophages v)astrocytes vi) axon number vii) demyelination, viii) retinalganglion cells (RGCs) number and iv) optic nerve lipidperoxidation (TBARS). LPS induced a significant decrease inVEP amplitude and PLR, a reduction in retinal anterogradetransport, an increase in Iba-1 and ED1 immunoreactivity,astrocytosis, demyelization, an increase in lipid peroxidation,and RGC loss. The pre-treatment with MEL prevented allthese alterations. The post-treatment with MEL preservedVEP amplitude and PLR. The treatment with melatoninprevented functional and histological alterations probablythrough an antioxidant mechanism. These results indicatethat melatonin could be a promissory resource in themanagement of ON.