CEFYBO   02669
CENTRO DE ESTUDIOS FARMACOLOGICOS Y BOTANICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Early retinal changes in an experimental model of Type 2 Diabetes characterized by postprandrial hyperglycemia
Autor/es:
SALIDO, EZEQUIEL; ARIAS, PABLO; DE ZAVALÍA, NURIA; ROSENSTEIN RE
Lugar:
Huerta Grande, Córdoba
Reunión:
Congreso; XXVI Congreso Anual de la Sociedad Argentina de Investigación en Neurociencias; 2011
Institución organizadora:
Sociedad Argentina de Investigación en Neurociencias
Resumen:
Insulin resistance and altered insulin release are the pathogenetic
mechanisms underlying the development of hyperglycemia in subjects with type 2
diabetes mellitus (T2DM). Microvascular complications, such as retinopathy,
arise as a consequence of chronic hyperglycemia, eventually leading to
blindness. Initially, the natural history of T2DM includes a period of normal
or near-normal fasting plasma glucose levels and marked postprandial glycemic
excursions. The impact of these glycemic spikes on retinal function is still
matter of controversy. The aim of the present study was to develop a model of
mild type 2 diabetes in rats (combining diet-induced insulin resistance and a
slight β-cell secretory impairment) in order to study early retinopathic
changes in rodents with slight fasting hyperglycemia and markedly elevated
postprandial glucose levels.
Adult male Wistar
rats received tap water and citrate buffer i.p. (Group 1), tap water with 30% w/v sucrose and citrate buffer i.p.
(Group 2), tap water and streptozotocin (STZ, 30 mg/kg i.p., Group 3), and 30%
sucrose and STZ (Group 4). At 6 and 12 weeks of treatment fasting and postprandial
glycemia, fructosamine and serum insulin levels were assessed. In addition,
i.p. glucose and insulin tolerance tests were performed. Retinal function (scotopic
ERGs), retinal morphology (optical microscopy), retinal lipid peroxidation (thiobarbituric acid reactive substances, TBARS) and NOS
activity (using 3H-arginine)
were also evaluated.
At 6 and 12 weeks of treatment, animals of Group 4
showed significant differences in most metabolic tests as compared with the
other groups. At 12 weeks of treatment, a significant decrease in the ERG a-
and b- wave and oscillatory potential amplitudes, a significant increase in
retinal TBARS levels, NOS activity, and
glial fibrillary acidic protein in Müller cells were observed in Group
4.
Only hyperglycemia resulting from the combination of a
sucrose-enriched diet and STZ injection induced significant biochemical and
functional retinal alterations.