| Objective :Diabetic Retinopathy(DR)can seriously affect the long-term quality of life of patients with diabetes,but the specific mechanism of DR Is not yet clear,and there are no clear and effective treatments yet.In this study,ischemic adaptation intervention was performed on diabetic cerebral ischemic tree shrews.H&E staining was used to observe the morphological and structural changes of retina,and serum and vitreous body fluid were taken to detect IL-6 concentration,so as to evaluate the influence of ischemic adaptation on IL-6 concentration in DR Serum and vitreous body fluid.Methods:1.Tree shrew grouping and model construction: 25 healthy adult male tree shrews with the same body weight of 130±30g were randomly selected as the Sham group(n=5)after adaptive feeding for 1 week.They were fed with basic diet and only underwent cerebral ischemia and pre-ischemic adaptation,without cerebral ischemia and post-ischemic adaptation intervention.Before the establishment of the diabetic tree shrew model,5 tree shrews fed a high-fat diet were randomly selected as Normal control+cerebral ischemia group(NI group,n=5),and a cerebral ischemia model was established by photochemical induction.The remaining 15 Diabetes Mellitus models were established,of which 5 were randomly selected as diabetes mellitus group(DM group,n=5).The remaining 10 diabetic tree shrews were randomly selected to establish cerebral ischemia model by photochemical induction,and 5 were randomly selected as Diabetes Mellitus+cerebral ischemia group(DI group,n=5).The other 5 patients were in Diabetes Mellitus+cerebral ischemia+postconditioning group(DIP group,n=5),who underwent post-ischemic adaptation intervention 4h after cerebral ischemia.2.Sampling and detection: 24 h after ischemia was used as the time window,the tree shrews were sacrificed,and the serum of each group was taken and the serum IL-6 concentration was detected by ELISA.Frozen sections were taken from the left eye of each group of tree shrews,and H&E staining was performed on the sections to observe the morphological and structural changes of the retina.IL-6 concentration was detected by ELISA in vitreous body fluids taken from the right eye of each group.Result:1.General situation: After 8 weeks of feeding in the basal diet group,the body weight of 5 tree shrews decreased compared with the initial body weight(P <0.05),and the blood glucose decreased compared with the initial blood glucose(P >0.05).Twenty tree Shrews were fed high fat diet for 8 weeks and their body weight increased(P < 0.01)and blood sugar increased(P < 0.01).After STZ injection,the body weight of tree shrews in DM group,DI group and DIP group was significantly decreased compared with that before STZ injection(P < 0.01),and fasting blood glucose was significantly increased compared with that before STZ injection(P <0.01)2.Serum indexes: Compared with Sham group,serum IL-6 concentration in DM group(P < 0.05),DI group and DIP group was increased(P < 0.01).Compared with NI group,serum IL-6 concentration of tree shrews in DI group was significantly increased(P < 0.01).Compared with DM group,serum IL-6 concentration of tree shrews in DI group was increased(P < 0.01).Compared with DI group,serum IL-6concentration in DIP group was significantly decreased(P < 0.01)3.Indicators of vitreous fluid: compared with Sham group,IL-6 concentration in vitreous fluid of NI,DM,DI and DIP groups was increased(P < 0.01).Compared with NI group,IL-6concentration in glass body fluid of tree shrews in DI group was significantly increased(P < 0.01).Compared with DM group,IL-6 concentration in glass body fluid of tree shrews in DI group was increased(P < 0.01).Compared with DI group,IL-6 concentration in glass body fluid of tree shrews in DIP group was significantly decreased(P < 0.01).4.Changes in retinal tissue structure: compared with Sham group,retinal cells in DM group were not arranged regularly with edema in all layers.The cells in the retina of tree shrews in group DI were further damaged,edema and intercellular space increased.The cell arrangement in retinal layers of tree shrews in DIP group was less pathological than that in DI group,suggesting that ischemic postconditioning could improve retinopathy in diabetic cerebral ischemic tree shrews.Conclusion:1.Tree shrews were selected as experimental animals for modeling to better simulate the pathophysiology of human type 2 diabetes mellitus and cerebral ischemia.2.Hyperglycemia and cerebral ischemia can increase IL-6 concentration in serum and vitreous body fluids of diabetic tree shrews and diabetic tree shrews.3.Hyperglycemia and cerebral ischemia promote inflammatory responses in diabetic retinopathy.4.Ischemic postconditioning can reduce IL-6 concentration in serum and vitreous body fluids of diabetic tree shrews and diabetic cerebral ischemic tree shrews. |
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