Effects of lycium bararum polysaccharides on blood glucose, blood fat and blood-retinal barrier in diabetic rats / 中华实验眼科杂志

ABSTRACT

Background The characters of diabetic retinopathy (DR) include capillary occlusion,microcirculation disturbance and retina neovascularization near ischemic areas of the retina.The pathogenic mechanism is still incompletely clear,but the primary mechanism of DR is the change of permeability of retinal blood capillary.Objective The aim of this study was to investigate the effect of lycium bararum polysaccharides (LBP) on the blood glucose,blood fat and permeability of blood-retinal barrier in diabetic rats.Methods Fifty-four clean adult SD rats were randomized into 4 groups.The diabetes mellitus models were created in 36 SD rats by injection of 45 mg/kg streptozotocin(STZ) via caudal vein.The rats with the blood glucose ＞ 16.7 mol/L were defined as the diabetic mellitus in 72 hours after injection.LBP of 200 rmg/( kg · d) was intragastriccally administered in 18 models once a day in LBP group,and equal volume of normal sodium was used at the same way in 18 models in DM group,and 18 normal rats were as normal control group.The rats were killed in 4,8 and 12 weeks respectively for the detect of blood glucose level,triglyceride,total cholesterol.The retina tissue were isolated for the quantification of vascular permeability using Evans blue method.Results The blood glucose level was significantly elevated in the DM group and LBP group compared with normal control group,and that in LBP group was obviously declined in comparison with the DM group with a 57％,40％,36％ fall off in 4,8,12 weeks respectively,showing a statistically significant differences( P＜0.05 ).The triglyceride concentration was considerably raised in the DM group compared with normal control group in all of the time points( P＜0.01 ),however,the rise of triglyceride concentration was found only in 12 weeks in LBP group(P＜0.05).The cholesterol level was increased in 8 and 12 weeks in DM group compared with normal control group and that of LBP group went up only in 12 weeks (P＜0.0l ).The Evans blue contents in dry retina tissue were(26.23±2.00),(29.78± 1.78 ) and( 34.08±3.03 ) μg/g in 4,8,12 weeks in the DM group,and those of LBP were ( 13.27 ±0.77 ),( 18.01 ± 1.77 ),( 25.05 ±1.50 ) μg/g,showing statistical differences between two groups ( P＜0.01 ).However,in comparison with normal control group ( 12.34 ±4.30,12.76 ± 2.11,12.45 ±4.40 μg/g),the Even blue content were elevated in various time points (P＜0.01 ).Conclusions LBP can suppress the increase of the blood-retinal barrier permeability in STZ-induced diabetic rat by lowing the levels of blood glucose,triglyceride and total cholesterol.These results suggest that LBP has a therapeutical effect on DR.