INVESTIGADORES
GERMAN Olga Lorena
congresos y reuniones científicas
Título:
Melatonin prevents apoptosis of photoreceptors during development in vitro
Autor/es:
MONACO S.; GERMAN L.; ROTSTEIN N.; ROSESTEIN R.; POLITI L.
Lugar:
Huerta Grande, Córdoba
Reunión:
Congreso; I Reunión conjunta en neurociencias (IRCN); 2009
Resumen:
Apoptosis, a
key process in the nervous system development, is required for establishing the
final number of neurons and removing neural precursors that form inappropriate
synapses. Abnormal apoptosis has been also involved in several
neurodegenerative diseases, including those occurring in the retina, like retinitis
pigmentosa and age related macular degeneration. In these diseases, apoptotic
photoreceptor (PR) death leads to vision loss. Hence, finding exogenous factors
that prevent PR apoptosis is relevant for treating these pathologies.
Considering that oxidative stress is involved in inducing photoreceptor death
and that melatonin (Mel), is a potent antioxidant, we investigated the effect
of Mel on PR apoptosis. For this purpose, pure retinal cultures from newborn
rats were incubated for six days with or without 40nM Mel, and finally fixed.
Cell viability was determinated by propidium iodide assay; apoptotic cell death
was evaluated by TUNEL assay and DAPI staining; and mitochondrial integrity was
analyzed using MitoTracker Red. In control conditions, in the absence of
trophic factors, PRs initiate an apoptotic process after 4 days in vitro. Mel
improved cell viability and reduced the number of apoptotic PRs after 6 days in
vitro, with a parallel increase in the amount of PRs preserving mitochondrial
membrane integrity. Moreover, Mel decreased about 75 the production of lipid
peroxidation products (thiobarbituric acid reactive species, TBARS) and by 50
that of reactive oxygen species (ROS). These results suggest that Mel prevents
PR apoptosis in vitro, probably by acting as an antioxidant, decreasing ROS
accumulation.