The effect of diabetes on vitreous levels of adiponectin and inflammatory cytokines in experimental rat model.

BACKGROUND: Diabetic retinopathy is one of the most common eye diseases faced by diabetic patients. It is a slow-progressing complication that results from damage to the blood vessels of the retina. OBJECTIVES: To investigate the role of adiponectin and inflammatory cytokines in the vitreous of diabetic rats. MATERIAL AND METHODS: The study was conducted in 3-4-month-old male albino Wistar rats (180-240 g). The animals were divided into 2 groups (n = 40 in each group): the diabetes group and the control group. A single dose of streptozotocin (STZ) (45 mg/kg) in citrate buffer (0.1 M; pH 4.5) was intraperitoneally (ip.) injected into the diabetes group rats. A single dose of citrate buffer was injected ip. into the control group rats. All subjects were sacrificed under intramuscular (im.) Na-thiopental (50 mg/kg) anesthesia. The rats' eyelids were opened with an eye speculum and vitreous samples were collected with 20G needles 4 mm posterior to the limbus. The levels of vitreous adiponectin, tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (INF-gamma), and matrix metalloproteinase (MMP)-2 and -9 were determined using a solid-phase sandwich enzyme-linked immunosorbent assay (ELISA). RESULTS: The levels of adiponectin, TNF-alpha, INF-gamma, MMP-2, and MMP-9 in the rat vitreous were significantly higher in the diabetes group than in the control group (p < 0.05). CONCLUSIONS: Elevated adiponectin, TNF-alpha, and INF-gamma levels in the vitreous may be diagnostically useful in diabetic retinopathy, and inflammatory cytokines in the vitreous may be pathogenically important in this concentration.