Ultrastructural Investigation of the Retinal Changes in Diabetic Rat (OLETF)

PURPOSE: To compare retinal ultra-structures of diabetic rats (OLETF, Otsuka Long-Evans Tokushima Fatty) with those of agematched non-diabetic rats (LETO, Long-Evans Tokushima Otsuka) using transmission electron micrography (TEM). METHODS: The body weights and blood sugar levels of the OLETF rats and LETO rats (n=5) were measured at 10 and 50 weeks of age. Using a TEM, we compared the ultra-structural changes between the retinas of the 50-week-old OLETF and LETO rats. We analyzed the sizes of the pericytes and the thicknesses of the retinal capillary basement membranes between the two groups. Comparisons were made using a Scion Image(R). RESULTS: The mean body weight and blood sugar levels of the 50-week-old OLETF rats were significantly higher than those of the LETO rats (p(R)0.05). The thicknesses of the retinal capillary basement membranes in the outer plexiform layer and the size of pericytes were significantly increased in the OLETF rats at 50 weeks of age (p<0.05). The number of nuclei in the inner nuclear layer and the outer nuclear layer (photoreceptor cell nuclei) significantly decreased (p<0.05). However, the height of the RPE cells and basal in-foldings showed no significant differences between the OLETF and LETO rats. CONCLUSIONS: The retinal changes in the OLETF rats were observed relatively early at 50 weeks of age. These changes are similar to those seen in human diabetic retinopathy. Change in the capillaries is one feature of early retinal change. OLETF rats may be a useful animal model in NIDDM to examine diabetic retinal changes.

Arecoline improved glucose and lipid metabolism in type 2 diabetic rats / 中国药理学通报

Aim To investigate the effects of arecoline on glucose and lipid metabolism in type 2 diabetic rats and its mechanisms in glucose metabolism.Methods A type 2 diabetic rat model was established by fed with high fructose-high fat diet.The animals were randomly divided into 7 groups: control group,high fructose-high fat diet group(HF)and high fructose-high fat diet+arecoline(1 mg?kg-1,5 mg?kg-1,10 mg?kg-1,20 mg?kg-1,50 mg?kg-1)groups.The blood glucose,lipid level,hepatic function and liver histology were measured.The mRNA expression of liver glucose-6-phosphatase(G6Pase),phosphoenolpyruvate carboxykinase(PEPCK),Forkhead Box O1(FoxO1)and peroxisome proliferator-activated receptor-? coactlvator-1? (PGC-1?)were observed through RT-PCR.Results In comparison with the high fructose-high fat diet group,the fasting blood glucose and TC of the rats were significantly decreased by arecoline in a dose-dependment manner in high fructose-high fat diet+arecoline group.But hepatic function was damaged by 10 mg?kg-1,20 mg?kg-1 and 50 mg?kg-1 arecoline.The mRNA expression of hepatic G6Pase,PEPCK,FoxO1 and PGC-1? was decreased by treatment with 1 mg?kg-1 and 5 mg?kg-1 arecoline compared with the high fructose-high fat diet group.Conclusions Low dose arecoline can decrease fasting blood glucose and TC in type 2 diabettic rats,and the mechanism in glucose metabolism may be related to its effect on the inhibition of hepatic gluconeogenesis.