The expression of opticin in vitreous body and retina of diabetes mellitus rats

Background: Diabetic retinopathy is a common complication of diabetes mellitus. Opcitin is a glycoprotein present in the vitreous body. Its role in diabetic retinopathy needs to be further defined.

Objective: Investigate and compare the mRNA and protein levels of opticin in vitreous body and retina in normal and diabetic rats.

Methods: Twenty-four male Sprague-Dawley (SD) rats were randomly divided into two groups (12/group), a streptozocin-induced diabetes (STZ) group and a control group. In the STZ group, 1% sterile STZ solution was injected into the rats intraperitonally (60mg/kg). An equal volume of sodium citrate buffer solution was administrated in the rats from the control group. The rats were sacrificed one month after various treatments. The eye bodies of three rats from each group were removed and fixed with 4% paraformaldehydeion for the following pathological analysis. Meanwhile, the vitreous bodies and retina of the other nine rats from each group were removed for the real-time PCR, immunohistochemistry, and western blot assays.

Results: The mRNA level of opticin in the vitreous body of diabetes mellitus (DM) rats was 5.66% of that of the control ones (p <0.01). The expression of opticin mRNA in retina of DM rats was 9.28% of that of the control ones (p <0.01). In addition, opticin protein was expressed in the vitreous body and retina of the normal rats, whereas it was negative in the DM ones.

Conclusions: The opticin expression in vitreous body and retina of diabetes rats was significantly decreased or even disappeared, which may suggest a key role of opticin in the development of diabetic retinopathy.