Experimental Study On The Effects And Mechanism Of Tangzhixiao On Insulin Resistant Hypertensive Rats

Objective To observe the effects of Tangzhixiao on insulin resistant hypertensive rat model and investigate its mechanism.Methods 4-5-week-old male Spraque-Darley rats were fed on high fructose diet to establish insulin resistant hypertensive rat model and then randomly divided into four groups.The rats were given high fructose diet or high fructose diet containing three doses of Tangzhixiao for 4 weeks . At the end of 4th week, the rats were sacrificed and their blood samples were taken, the concentration of serum glucose, insulin , leptin, lipids and erythrocyte calcium and magnesium were determined.The HOMA model was used to evaluate insulin resistance (IR). The relationships between each parameters were analyzed.Results1. SBP, insulin level and HOMA-IR in rats fed on high fructose were significant higher than those in normal control group, following hyperleptinemia and dislipidemia (p<0.05 or p<0.0l) .2. In rats fed on high fructose, HOMA-IR was strongly positively related to SBP, leptin level ,triglyceride (TG ) and erythrocyte calcium, while negatively to high-density lipoprotein-cholesterol (HDL-C) and erythrocyte magnesium(;K0.05 or P<0.0l) .3. In rats fed on high fructose, leptin level was remarkbly positively related to SBP,insulin level, HOMA-IR and triglyceride (TG ) (P<0.05 or p<0.0l ) , but not correlated to serum glucose, total cholesterol (TC), HDL-C and erythrocyte calcium and magnesium (all p>0.05 ) .4. The insulin,leptin level and HOMA-IR of middle dose of Tangzhixiao group were decreased than those in model control group ( all p<0.05 ) , but no significant changes were found in low and high dose of Tangzhixiao groups ( all p>0.05 ) .5. TG level in low and middle dose of Tangzhixiao groups was decreased than that in model control group (both P<0.05 ) . No significant change was found in high dose of Tangzhixiao group ( p>0.05 ) .Compared with model control group, middle dose of Tangzhixiao group produced a decrease in TC level, meanwhile HDL-C level was significant increased (both P<0.0l ) .There were no significant difference of TC and HDL-C in low and high dose of Tangzhixiao groups (all P<0.01)6. Erythrocyte calcium was decreased and erythrocyte magnesium was increased in middle dose of Tangzhixiao group (both P<0.05 ) .No significant changes were found in low and high dose of Tangzhixiao groups (all P>0.05 ) .7. Three doses of Tangzhixiao groups show no significant difference in serum glucose and SBP (all P>0.05 ) .Conclusion l.High fructose diet can induce insulin resistance, hypertension, hyperleptinemia and dislipidemia in the SD rats. 2. Hypertension may be related to insulin resistance and hyperleptinemia. 3. Tangzhixiao can effectly increase insulin sensitivity and reduce lipids. Apart from those effects, it has moderate influence on blood pressure.4. The mechanism of Tangzhixiao may be obtained by improving insulin resistance ,decreasing leptin level and regulating calcium and magnesium metabolism.