Effect Of Astragalus And Dark Plum Extracts On Blood Glucose And Insulin Sensitivity In GK Rat

Objective:To observe the effect of Astragalus and Dark plum extracts on blood glucose and insulin sensitivity of GK rats, further explore its mechanism and provide experimental basis for clinical medication.Methods : 32 male GK rats, 4 weeks old, adaptive feeding 1 week, randomly divided into 4 groups: model control group, positive control group, huangqi- wumei 1.3 g·kg-1 group and huangqi-wumei 5.2 g·kg-1 group, meanwhile 8 male 4-week-old Wistar rats set as blank control group. Astragalus and Dark plum treatment groups were respectively given Astragalus and Dark plum formula granule 1.3 and 5.2 g·kg-1 by lavage; positive control group were given metformin hydrochloride 0.15 g·kg-1 by lavage; model control group and blank control group were given normal saline by lavage. During the experiment measuring body weight, fasting blood glucose and OGTT in rats. Drug intervention 10 weeks, after fasting 15 h, intraperitoneal injection of 10% chloral hydrate(3 ml·kg-1) anesthesia, then collection blood from the heart and obtaining the liver and pancreas tissue which part of fixed with 4% paraformaldehyde and the remainder stored at-80℃. Measuring fasting serum insulin and tumor necrosis factor-α by enzyme- linked immuno sorbent assay; detecting serum free fatty acid content by copper ion colorimetry; testing liver Ins R and IRS-1 protien expression by western blot; morphological observa tion on the liver and pancreas structure by HE staining.Rseults:(1) After intervention 10 weeks, Compared with model group, body weight in each dose of Astragalus and Dark plum extracts group rats was siginificantly lighter(p<0.05).(2) Before the intervention, compared with the blank group of Wistar rats, GK rats the blood glucose leval of OGTT and the glucose area under the curve significantly increased(p<0.05). After intervention 10 weeks, compared with model group, fasting glucose was decrease in positive control group and every dose of Astragalus and Dark plum extracts group(p<0.05), and the glucose area under the curve was reduced in positive control group and Astragalus and Dark plum 5.2 g·kg-1 dose group(p<0.05).(3) Compared with the blank group, model contral group FINS and HOMA-IR was significantly rise, HOMA-ISI and HOMA-β was decrease(p<0.05). Compared with model group, positive control group and Astragalus and Dark plum 5.2 g·kg-1 dose group FINS and HOMA-IR was significantly decrease, HOMA-ISI andHOMA-β was rise(p<0.05), the indicators also ameliorated in Astragalus and Dark plum 1.3 g·kg-1 dose group, but only decrease of HOMA-IR and rise of HOMA-β has statistically significant(p<0.05).(4) Compared with the blank group, cholesterol and high-density lipoprotein cholesterol were increased in GK rats(p<0.05); but compared with model group, cholesterol and high-density lipoprotein cholesterol were unchanged in positive control group and every dose of Astragalus and Dark plum extracts group.(5) Compared with the blank group, serum tumor necrosis factor-α and free fatty acid content were increased in model control group(p<0.05). Compared with model group, serum tumor necrosis factor-α and free fatty acid content were reduced in positive control group and every dose of Astragalus and Dark plum extracts group(p<0.05).(6) Compared with the blank group, the protien expressions of Ins R and IRS-1 in liver were reduced in model group(p<0.05). Compared with model group, the protien expressions of Ins R and IRS-1 in liver were increased in positive control group and every dose of Astragalus and Dark plum extracts group(p<0.05).Conclusions: Astragalus and Dark plum extracts can reduce blood glucose and ameliorate insulin sensitivity. Astragalus and Dark plum extracts also can improve insulin sensitivity and pancreatic β-cell function through reduced serum tumor necrosis factor-α and free fatty acid content, increased the protien expressions of Ins R and IRS-1 in liver.