Qing Chu

Northeast Institute of Geography and Agroecology, Beijing, Beijing Shi, China

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Publications (2)5.4 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: To evaluate the protective effect of intravitreal injection of exendin-4 analogue (E4a) in early diabetic retinopathy (DR) and to explore its possible mechanism. Forty Sprague-Dawley rats were divided into three groups: normal (N), diabetic (D), and E4a-treated diabetic rats (E4a). Diabetes was induced by streptozotocin. Rats in the E4a group were treated with E4a (0.1 μg/2μL/eye), whereas the N and D groups were treated with the equivalent volume of normal saline. Electroretinography was performed at 1 month and 3 months after diabetes onset. Thicknesses and cell counts in each layer of the retina were evaluated. The concentration of glutamate was measured by high-performance liquid chromatography (HPLC). Expressions of glucagon-like peptide-1 receptor (GLP-1R) and GLAST (excitatory amino acid transporter) were detected at mRNA and protein levels and verified by immunohistochemistry in vitro and in vivo. The rMc-1 cells were cultured under high-glucose medium (25 mM), which mimicked diabetic conditions. Effects of E4a (10 μg/mL) were also tested in the rMc-1 culture system. E4a prevented the reduction in b-wave amplitude and oscillatory potential amplitude caused by diabetes. It also prevented the cell loss of outer nuclear layer and inner nuclear layer; the thickness and cell count in the outer nuclear layer were decreased in 1-month diabetic rats. The concentration of glutamate in the retina was higher in diabetic rats and was significantly reduced in the E4a-treated group. Consistent with such changes, retinal GLP-1R and GLAST expression were reduced in the diabetic retina but upregulated in E4a-treated rats. No improvement was found in the retina in both functional and morphologic parameters 3 months after treatment. Intravitreal administration of E4a can prevent the retina, functionally and morphologically, from the insults of diabetes in rats. GLP-1R and GLAST were proved to exist in the rat retina, and their lowered expressions in the diabetic retina might be related to retinal damage by increasing the retinal glutamate. E4a might protect the retina by reducing the glutamate level through upregulating GLP-1R and GLAST, as observed in retinal Müller cells in this study, but this protective effect was transient. Thus, this could be a potential approach for the treatment of DR.
    Investigative ophthalmology & visual science 01/2011; 52(1):278-85. · 3.43 Impact Factor
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    ABSTRACT: To profile the pattern of gene expression in diabetic rat retinas with or without intravitreal injection of erythropoietin. By using streptozotocin-induced diabetic rats, after intravitreal injection of erythropoietin, neurosensory retinas were collected to determine the effect of erythropoietin on gene expression. Three groups of Sprague-Dawley rats were studied: normal control (15), diabetic rats with saline injection (15) and diabetic rats with intravitreal erythropoietin treatment (15). Diabetes was induced by intra-peritoneal injection of streptozotocin. Intravitreal injection of erythropoietin was performed at the following time points: 0, 30 and 120 days after diabetes onset. Four days after each injection at above-mentioned time points, the retinas were harvested for microarray assay. The real-time PCR was used to evaluate the microarray data. Genes encoding inflammatory factors, such as interleukin-2 and interleukin-11, which were upregulated in the diabetic retinas, were restored after erythropoietin treatment. Genes encoding pro-apoptotic effectors, like Tnfrsf5, Bid3 and Bcl2l1, were also upregulated in diabetic rats and attenuated in erythropoietin-treated group. In addition, real-time PCR were employed to confirm the changes of the genes Trex2, G1P2, DHX58, RGD1311906 and LOC689064, which have not been reported in diabetic retinopathy. Intravitreal erythropoietin treatment is able to normalize the gene expression responsible for pro-apoptotic and inflammatory responses noted in diabetic retinas.
    Clinical and Experimental Ophthalmology 10/2010; 39(2):142-51. · 1.96 Impact Factor

Publication Stats

13 Citations
128 Views
5.40 Total Impact Points

Institutions

  • 2010
    • Northeast Institute of Geography and Agroecology
      • Institute of Health Sciences
      Beijing, Beijing Shi, China