[The role of glucose control with intensive insulin therapy on retinal vessels of early diabetic rats].
OBJECTIVE
To observe the role of blood glucose control on morphology changes of retinal vessels and retinal vascular endothelial growth factor (VEGF) expression in early diabetic rats.


METHODS
Diabetes was induced in 8-week-old male Wistar rats by a single intraperitoneal injection of Streptozotocin (STZ). After 3 weeks, the animals were randomly divided into four groups: (1) normal rats group, (2) diabetic rats group, (3) diabetic rats with glucose controlled group, received intensive insulin therapy for 20 days, and (4) diabetic rats with uncontrolled blood glucose group, received unregular insulin therapy, which caused the abrupt fluctuation of glucose. After the treatment period, the animals were perfused with 30 mg/ml Fluorescein isothiocyanate-dextran (FITC-Dextran). The eyes were enucleated and fixed in 4% paraformaldehyde immediately. Retinal flat mounts and paraffin sections were prepared. Morphology of impaired retinal vessels and retinal VEGF expression were assessed by immunofluorescence stain and image analysis.


RESULTS
The flat-mounted retinas showed more FITC-Dextran aggregated locally at vessels and capillary meandered or dilated in STZ-diabetic rats with uncontrolled blood glucose than in STZ-diabetic rats with controlled blood glucose. Retinal VEGF expression decreased in group 3 compared with group 2 or with group 4. The statistical difference was significant (P < 0.05).


CONCLUSIONS
Strict control of blood glucose by insulin could decrease VEGF expression in retina and protect retinal vessels from impairing in early STZ-diabetic rats.
Wang
Yulin
Y
Shenzhen People Hospital, Shenzhen 518020, China.
Ma
Pingping
P
Li
Bin
B
Lin
Shaofen
S
Wu
Yan
Y
Feng
Jinshang
J
Tang
Shibo
S
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental; D003930:Diabetic Retinopathy / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000627:therapeutic use*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012171:Retinal Vessels / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat