Effects and Mechanisms of Baicalin on Activation of Retinal Microglial Cells in Dia-betic Rats
OBJECTIVES To explore the impact of baicalin on the activation of retinal microglial cells in diabetic rats and its underlying mechanism.METHODS Diabetes model was induced in rats via intraperitoneal injection of streptozotocin,and they were randomly assigned to the model group(MG)and baicalin group(BG).Healthy rats constituted the control group(CG),with 12 rats in each group.The BG rats were orally administered a baicalin solution(50 mg/kg)daily,while CG and MG rats received an equivalent volume of distilled water orally for 12 weeks.After 12 weeks,blood glucose levels were measured,and the right eyeballs were enucleated for histological examination using hematoxylin-eosin(HE)staining to observe retinal morphology.Immunohistochemistry was used to detect the expression of cluster of differentiation 68(CD68)protein in retinal microglial cell clusters.Immunofluorescence was employed to assess the expression of signal transducer and activator of transcription 3(STAT3)protein.Real-time quantitative PCR(RT-qPCR)was conducted to measure the relative expression levels of interleukin-6(IL-6)and STAT3 mRNA.RESULTS(1)Retinal morphology:Compared to the CG group,MG rats showed a significant increase in loss of retinal ganglion cells(RGC),while BG rats exhibited an increase in RGC count.Retinal thickness was reduced in the MG group compared to the CG group,while the BG rats had a thicker retina than the MG rats.(2)Microglial cells:In the CG group,microglial cells were localized in the inner nuclear layer.MG rats had an increased number of microglial cells distributed throughout every layer of the retina,whereas BG rats had fewer microglial cells compared to the MG rats,and microglial cell migration was restricted.CD68 expression in retinal microglial cells was higher in the MG group than in the CG group(t=7.348,P=0.000),and lower in the BG group than in the MG group(t=2.449,P=0.019),with all statistically significant differences.(3)STAT3,IL-6:In the CG group,retinal STAT3 expression was mainly distributed in the inner plexiform layer.MG rats exhibited abundant positive expression of STAT3 in every retinal layer,while BG rats showed significantly weaker STAT3 expression compared to the MG group.The expression of STAT3 and IL-6 mRNA in the MG group was higher than in the CG group(tSTAT3=9.935,tIL-6=17.501,both P= 0.000),and lower in the BG group than in the MG group(tSTAT3=8.432,tIL-6=9.944,both P=0.000),with all statistically significant differences.CONCLUSIONS Baicalin can inhibit the activation of retinal microglial cells in diabetic rats,and its mechanism may be related to the IL-6/STAT3 signaling pathway.
万方数据
维普
