High-Fat Diet Induces Toll-Like Receptor 4-Dependent Macrophage/Microglial Cell Activation and Retinal Impairment

作者：Lee Jong Jer; Wang Pei Wen; Yang I Hui; Huang Hsiu Mei; Chang Chia Shiang; Wu Chia Lin; Chuang Jiin Haur^*

来源：Investigative Ophthalmology & Visual Science, 2015, 56(5): 3041-3050.

DOI：10.1167/iovs.15-16504

• CD11b
• CD45
• high-fat diet
• oxidative stress
• retina
• toll-like receptor 4

PURPOSE. The toll-like receptor 4 (TLR4) signaling pathway is involved in chronic inflammation and insulin resistance, which are associated with obesity and diabetes mellitus. In the present study, a model of high-fat diet (HFD) feeding of mice was used to investigate the role of TLR4 in overnutrition-and obesity-associated inflammation and infiltration of macrophages and microglia in the retina.
METHODS. Wild-type C57BL/6 and TLR4 knockout (TLR4KO; B6.B10ScN-Tlr4(lps-del)/JthJ) mice were fed a HFD or control chow diet (CD) for 6 months. The TLR4 expression, the relative increase in macrophages/microglia (CD11b(+) and CD45(+) cells), the presence of markers of oxidative stress (gp91phox and malondialdehyde; MDA), and DNA damage (phosphorylated histone H2AX; gamma H2AX) were assessed by real-time PCR and immunofluorescence studies.
RESULTS. The HFD for 6 months showed increased obesity, glucose intolerance, and insulin resistance in mice. Toll-like receptor 4 expression was found in vascular pericytes at the inner retina. Increased CD11b(+) and CD45(+) cells, phosphorylated NF-kappa B, interleukin-6, gp91phox, MDA, and gamma H2AX were observed in the retina of mice fed a HFD compared to CD counterparts. TLR4KO mice did not show the adverse effects of HFD.
CONCLUSIONS. Our results indicate that HFD-induced macrophage/microglial cell activation and retinal impairment were reduced in the absence of TLR4. The findings suggest that TLR4 is implicated in the pathogenesis of retinal diseases caused by metabolic disorders.

• 出版日期2015-5
• 单位长春大学