Expression of PFKFB3 and S1P2 in the retina of type 2 diabetic rats and the intervention effect of tBHQ / 眼科新进展

ABSTRACT

Objective To investigate the expression of 6-phosphofructo-2-kinase /fructose-2,6-bisphosphatase-3 (PFKFB3) and sphingosine 1-phosphate receptor 2 (S1 P2) in the retina of rats with type 2 diabetes mellitus (DM) and to explore the correlation of tertiary butylhydroquinone (tBHQ) with PFKFB3 and S1P2.Methods Together 60 male SD rats were divided into normal control group (NC group),diabetes mellitus group (DM group) and tBHQ group.Type 2 DM model was induced in the latter two groups.The rats in tBHQ group were given 10 g · L-1 tBHQ in high-fat and highsugar diet 1 week after successful modeling,while DM rats were fed with high-fat and high-sugar diet continuously.At 4 weeks and 12 weeks after tBHQ intervention,blood samples were taken from the hearts of rats in each group,and serum contents of fasting plasma glucose (FPG) and fasting serum insulin (FINs) were measured.Immunohistochemistry and qRT-PCR were taken to detect the distribution and expression of PFKFB3,S1 P2 and vascular endothehal growth factor (VEGF) mRNA and protein in the retina,and TUNEL methods were used to detect apoptosis index of retinal ganglion cells of rats in each group.Results There were significant difference in the FPG and FINs levels of the three groups at 4 weeks and 12 weeks (all P =0.000).Light microscopy test showed that positive expressions of PFKFB3,S1 P2 and VEGF protein were found in all groups at 4 and 12 weeks,which were mainly located in the retinal ganglion cell layer and the inner nuclear layer.Immunohistochemistry and qRT-PCR showed that the difference in relative expressions of PFKFB3,S1P2,VEGF protein and mRNA in the retina at different times after modeling were statistically significant (all P ＜ 0.05).At 4 and 12 weeks,the expression levels of PFKFB3,S1P2 and VEGF in DM group were higher than those in NC group,but their expressions in tBHQ group were significantly downregulated when compared with DM group,and all differences were statistically significant (all P ＜ 0.05).Compared with 4 weeks,PFKFB3,S1 P2 and VEGF mRNA and protein in DM group were overexpressed at 12 weeks,and the expression level of S1 P2 in tBHQ group at 12 weeks was lower than that at 4 weeks,and the differences were statistically significant (all P ＜ 0.05).TUNEL assays showed that there was significant difference in the apoptotic index (AI) of retinal ganglion cells of rats in each group at different times after modeling (all P ＜ 0.05).DM group had higher AI than NC group (P ＜ 0.05),and tBHQ group was lower than DM group (P ＜ 0.05);Compared with 4 weeks,DM group had increased AI at 12 weeks while tBHQ group had decreased AI (both P ＜ 0.05).Conclusion PFKFB3,S1P2 and VEGF are involved in the pathological process of the retina of type 2 DM rats,which may play a role through the PFKFB3 / VEGF / S1P2 signaling pathway and may be related to the apoptosis of retinal ganglion cells.And it is indicated that tBHQ has a protective effect on the retina of type 2 DM rats.