ABSTRACT
Objective To observe the effects of A2a adenosine receptor antagonist SCH442416 and ZM241385 on the expression of glutamine synthetase(GS) and L-Glutamate/L-Aspartate Transporter(GLAST) in rat retina under chronic ocular hypertension model.Methods Rat chronic ocular hypertension models were induced in the right eye of 12 male Sprague Dawley rats by blocking three episcleral veins,the left eye as control one.Intraocular pressure (IOP) was measured and compared at postoperative 1 week,2 weeks and 3 weeks.54 male chronic ocular hypertension rats were divided into 3 groups randomly,topically applying A2a adenosine receptor antagonist SCH442416,ZM241385 and carrier,respectively,three times a day for three weeks.At three weeks,mRNA and protein expression of GS and GLAST in rat retina were analyzed by RealTime-PCR and Western-blot.Results The average IOP of the modeling eyes at postoperative 1 week,2 weeks and 3 weeks were higher than that of the control eyes (all P ＜ 0.05).The mRNA and protein expression of GS and GLAST in the retina of SCH442416 and ZM241385 groups increased significantly compared to the carrier group (all P ＜ 0.05).However,the differences of mRNA and protein expression of GS and GLAST between SCH442416 and ZM241385 groups was not significant(all P ＞ 0.05).Conclusion Rat chronic ocular hypertension model can be induced by blocking three episceral veins successfully and effectively.A2a adenosine receptor antagonist SCH442416 and ZM241385 increase the expression of GS and GLAST.There seems no difference between the effects of these two drugs.
ABSTRACT
Objective To investigate the protective effect of brain derived neurotrophic factor (BDNF) on Müller cells in the retina of diabetic rats.Methods A total of 54 healthy male SD rats were recruited and randomly divided into control group,diabetic group and BDNF group.Then a diabetic model was established by intraperitoneal injection of streptozotocin in rats of diabetic and BDNF groups.Preparation of BDNF injection was performed using PBS balanced salt solution containing 0.1 g · L 1 BSA.The BDNF group was given BDNF injection,while the control and diabetic group were injected with equal dose of PBS balanced salt solution 4 weeks after successful modeling.And after 8 weeks,the expression of L-glutamate/L-aspartate transporter (GLAST),glutamine synthetase (GS) and synaptophysin (SYN) were detected by immunofluorescence technique and Western blot,and the content of glutamic acid in retina was determined by glutamic acid determination kit.Results Compared with the control group,the expression of GLAST,GS and SYN were significantly decreased in diabetic group,and the content of glutamic acid was increased significantly (all P ＜ 0.01).Compared with the diabetic group,the expression of GLAST,GS and SYN were increased in BDNF group,and the glutamate level was decreased significantly (all P ＜0.01).Conclusion In the early stage of diabetic retinopathy,administration of exogenous BDNF can unregulated the expression of GLAST,SYN and GS and improve the function of Müller cells to protect RGC against damage,suggesting that BDNF has neuroprotective effects on Müller cells in retina of rats with diabetic retinopathy.