ABSTRACT
BACKGROUND: With the development of the economy and improvements in living standards, the incidences of diabetes mellitus (DM) and diabetic retinopathy (DR), which is a complication of DM, are on the rise. AIM: To analyze early DR in patients with macular zone changes in biological images using optical coherence tomography angiography. METHODS: A prospective case study was performed on 59 participants: 35 healthy eyes (control group), 35 eyes with diabetes but no DR group (no DR group), and 35 eyes with mild DR (NPDR group). All quantitative comparisons of parameters, including the fovea vascularity area, circularity index, and vascular complexity parameters, were performed using a biological image analysis software. RESULTS: The foveal avascular zone (FAZ) area, FAZ circularity index, number of branches in the area, and the total of the single branches' length in the area was 0.366 ± 0.031, 0.834 ± 0.037, 3241.8 ± 268.3, and 3.860 × 107 ± 0.194 × 107, and 0.421 ± 0.030, 0.739 ± 0.023, 2956.6 ± 476.4, and 3.177 × 107 ± 0.161 × 107 in the no DR group and the NPDR group, respectively, which were significantly different from the corresponding parameters of the control group (P < 0.05). Moreover, there were significant differences between these two groups (P < 0.05). CONCLUSION: This study shows that early microcirculation changes in the macular area of the retina is associated with disease progression. Early changes in DR can be analyzed using optical coherence tomography angiography.
ABSTRACT
BACKGROUND: Diabetic retinopathy is severe damage to the retina caused by complications of diabetes, and is the prevailing cause of blindness. Accumulating evidence from both animal models and humans suggests that the inflammatory process plays a key role in the development of diabetic retinopathy and is facilitated by innate immune response. The aim of this study was to examine whether the TLR4 signaling pathway was involved in the streptozotocin-induced diabetic rat retina. METHODS: Diabetes was induced by a single intraperitoneal injection of streptozotocin, and rat diabetic retinopathy was examined at 4 weeks of diabetes duration. Then the accumulated leukocytes were counted in vivo by acridine orange leukocyte fluorography, and the retinal vascular permeability was measured by the Evans blue assay. The expressions of TLR4 and its downstream signaling molecules were measured by RT-PCR or Western blot respectively. To evaluate the effect of blocking TLR4 on diabetic retinopathy, TAK-242, a selective TLR4 antagonist, was administered by intraperitoneal injection. RESULTS: Our results showed that the retina of diabetic rats demonstrated accumulated leukocytes and retinal vascular permeability. The mRNA and protein expressions of TLR4 were upregulated in streptozotocin-treated diabetic rat retina. Furthermore, the protein levels of TLR4 downstream signaling molecules were significantly increased in streptozotocin-treated animals. In addition, the protein levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and interferon (IFN)-ß, three downstream proinflammatory cytokines of TLR4 signal transduction pathway, were also markedly increased in diabetic rats. Administration of TAK-242 attenuated leukocytes accumulated and retinal vascular permeability, and decreased TLR4 downstream signaling molecules and proinflammatory cytokines in streptozotocin-induced animals. CONCLUSIONS: Together, these data have demonstrated that TLR4 has a critical role in streptozotocin-induced diabetic retinopathy at the level of inflammatory cytokine induction, in both the MyD88-dependent and MyD88-independent pathways. TLR4 may become a new potential pharmacological target for treating diabetic retinopathy.
