The Preventive And Therapeutic Effect Of Licorice Flavonoids On Experimental Type 2 Diabetes In Rats

【Objective】To study the effect of licorice flavonoids (LF) on serum levels of fasting blood glucose (FBG), lipids, adipocytokines, antioxidation capability and other biochemical indicators. And to study the preventive effect of LF on increase of FBG and lipids induced by high-fat and high-sugar diet combined with low-dose streptozotocin injection.【Methods】The type 2 diabetic rat model was replicated by high-fat and high-sugar diet combined with low-dose streptozotocin (STZ, 35mg/kg) injection. The diabetic rats were divided into model group (DM), high-dose treatment group (HLF) and low-dose treatment groups (LLF). Other 20 normal rats were divided into control group and control treatment group (CLF). Rats in different groups were administered with LF (100mg or 300mg/(kg body·d)) or solvent (1,2-propanediol) respectively. 5w later, levels of fasting blood glucose (FBG), triglycerides (TG), total cholesterol (TC), free fatty acids (FFA), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), insulin (INS), tumor necrosis factor alpha (TNF-α), leptin, total antioxidation capability (T-AOC), superoxide dismutase (SOD), gluthathione peroxidase (GSH-PX) and malondialdehyde (MDA) in serum of all experimental animals were examined. The preventive experimental rats were divided into preventive control group (PC) and preventive treatment group (PLF). Rats in these two groups were fed with high-fat and high-sugar diet and administered meanwhile with solvent or LF (300mg/(kg body·d)) respectively for 6w. 6d after injected STZ (35mg/kg), the levels of FBG, TG, TC, HDL-C, LDL-C and T-AOC were examined. Liver, kidney, fat around kidney, epididymis and epiloon were excised and weighed. Insulin sensitivity index (ISI), HDL-C/TC, liver index, kidney index and the relative weight of abdominal adipose tissue of all experimemtal rats were calculated. The tissue sections of pancreastic, liver and kidney were prepared, dyed with HE and pathological changes of were evaluated. 【Results】High-dose LF (300mg/(kg body·d)) treatment significantly decreased the levels of FBG, TG, TC, FFA, LDL-C, TNF-α, Leptin, MDA, liver index and kidney index (P<0.05 or P<0.01). At the same time, high-dose LF treatment increased the levels of T-AOC, SOD, GSH-PX, ISI, HDL-C/TC and the relative weight of abdominal adipose tissue (P<0.05 or P<0.01). LF preventive treatment significantly inhibited the increase in levels of FBG, TG, TC, LDL-C and liver index (P<0.05 or P<0.01) caused by combination of high-fat-high-sugar diet and low dose STZ injection, it also significantly increased the levels of T-AOC, HDL-C/TC and inhibited the decrease in relative weight of abdominal adipose tissue (P<0.05 or P<0.01). High-dose LF ameliorated the pathological lesion of pancreastic, liver and kidney tissue. Compared with high-dose treatment, low doses of LF was less effective.【Conclusion】LF has significant suppressive effect on the increase in blood glucose level and the lipid metabolic disorders in experimental type 2 diabetic rats. LF is also effective in prevention of occurrence of experimental T2DM in rats.