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

Abstract

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.