| Objective: Gardeniae and Sojae Praeparati Decoction (GSPD) ,a traditionary prescriptions in Shanghan Lun, are used widely in the treatment of deficient dysphoria .It was reported that gardenia jasminoides ellis and Semen Sojae preparatrm (SSP) had the effects of decreasing blood glucose and improving IGT. Very few studies have been reported about the working mechanisms that GSPD improves insulin resistance. In our study, insulin resistance rats model was utilized ,through observing the InsR mRNA expression in its hepatic tissue and the change of relative factors which affect insulin signal transduction. For the purpose of providing theoretical and experimental evidences, enlarging new usage of the traditional prescription, we systematically approached the mechanism of GSPD in improving insulin resistance of diabetes mellitus at the global and molecule level. In addition, through observing the blood pressure and the AT1 mRNA expression in spontaneous hypertension rats, we initially study the effect and the possible mechanism of GSPD on Angiotensin II which affect insulin signaling pathway in spontaneous hypertension rats.Methods:1 the effect of GSPD on insulin resistance of type 2 diabetes ratsThe male healthy wistar rats were given a low dose Streptozotocin (STZ) by peritoneal injection and fed high-fat forage to establish the classical model of type 2 diabetes mellitus. The model Wistar rats were divided into 5 groups at random according to the fasting plasma glucose(FPG): Model control group, low dose GSPD(4 g/kg), middle dose GSPD(8g/kg), high dose GSPD(16 g/kg) and rosiglitazone (RSG) group(1.8 mg/kg), 10 Normal rats was selected for Normal control group which was given distilled water. After GSPD was continuously administrated 10mL/kg for 8 weeks, the blood, pancreas and liver were gotten for detection the relevant indexes.1.1 The detection of the blood biochemical indexes : the rats were decapitated to get blood, centrifugated and obtained the blood serum at low temperature, detected the FPG, FINS, TNF-a, HbA1c, SOD, MDA, etc. and calculated the ISI by ISI=ln[1/(FPG×FINS)].1.2 The detection of the histomorphology of pancreas: the pancreas were taken and HE stain, the change of the histomorphology of pancreas were observed.1.3 Detection of the expression of InsR mRNA in liver cell membrane: the liver were gotten quickly, expression of the InsR in liver was detected by RT-PCR method.2 The effect of GSPD on the expression of AT1 mRNA in the spontaneous hypertension rats(SHRs)According to blood pressure to select SHR and divide into 5 groups at random,control group,captopril group(2 mg/kg),low dose GSPD (4 g/kg),middle dose GSPD(8 g/kg), high dose GSPD(16 g/kg), GSPD and captopril were administered orally 10 mL/kg for 28 days , blood pressure was measure every week.2.1 The effect of GSPD on the blood pressure in SHRDetected the value of contractive pressure by BESN-II .2.2 The detection of the expression of AT1R mRNA in aortaTotal RNA in aorta was extracted by Trizol method, expression of the AT1R mRNA in aorta was detected by RT-PCR method.2.3 The detection of expression level of AT1R mRNA in cardiac muscleTotal RNA in cardiac muscle was extracted by Trizol method, expression of the AT1R mRNA in cardiac muscle was detected by RT-PCR method.Result:1 The effect of GSPD on insulin resistance(IR) in type 2 diabetes mellitus rats1.1 The effect of the blood biochemical indexes1.1.1 The effect of FPG and HbA1c: the level of FPG and HbA1c in model group were markedly higher than that in control group(P<0.01), and all the group of GSPD were lower than that in the model group (P<0.01or P<0.05). 1.1.2 The effect of FINS and ISI: the level of FINS in model group were markedly higher than that in control group(P<0.01); and the low, middle, high density of GSPD remarkably lower than that in the model group(P<0.01).The value of ISI in the model group were remarkably lower than that in control groupP<0.01); all the group of GSPD were apparent higher than those in the model group(P<0.01).1.1.3 The effect of TNF-α: the level of in the model group were remarkably higher than that in the control group(P<0.01); the low, middle, high density group of GSPD were apparent lower than those in the model group(P<0.01 or P<0.05).1.1.4 The effect of SOD and MDA: the level of SOD in the model group were markedly lower than those in the control group (P<0.01), and the middle, high density group of GSPD were apparent higher than those in the model group(P<0.01 or P<0.05), the low density group of GSPD were higher than model group, but had no significant difference (P>0.05). The level of MDA in the model group were apparent higher than that in the control group (P<0.01), all the group of GSPD were remarkably lower than that in the model group (P<0.01 or P<0.05).1.2 The effect of GSPD on morphology of pancreatic tissue : Compared with the control group, the quantity of islet cells in model group was obviously lower, the volume of islet cells was decreased, the cytoplasm of some islet cells were vacuolar degenerative, the Cell Nucleus were pycnotic. Compared with the model group, the pancreatic tissue of the middle, high density group of GSPD and RSG group were more integral, the configuration of islets of langerhans was replete, the border was clear, the quantity of islet cells was obviously higher, the quantity of vacuoles of the cytoplasm were obviously lower.1.3 The effect of the expression of InsR mRNA in liverThe expression level of InsR mRNA in the model group were apparent lower than that in the control group(P<0.01); all the group of GSPD and RSG group were apparent higher than those in the model group (P<0.01 or P<0.05). 2 The effect of GSPD on RAS in SHR2.1 The effect of blood pressure in SHRCompared with the model group,the blood pressure in low density group of GSPD tended to decline, but have no significant difference (P>0.05), middle, high GSPD and the captopril group were apparent decreased (P<0.01 or P<0.05).2.2 The effect of the expression of AT1R mRNA in aortaCompared with the model group, expressions of middle does GSPD, high does GSPD and the catopril group were obviously decreased (P<0.01), expression of low GSPD tended to decline, but had no significant difference (P>0.05).2.3 The effect of expression of AT1R mRNA in cardiac muscleCompared with the model group, expressions of all the group of GSPD and the catopril group were obviously decreased (P<0.01 or P<0.05).Conclusion:1 GSPD could decrease the FPG,HbA1c,FINS level, ameliorated the injuries in pancreas of type 2 diabetes mellitus rats,and had the effect to improve insulin sensibility and insulin resistance.2 The amendent insulin resistance of GSPD was likely to relate with up-regulating the expression of InsR mRNA in liver.3 GSPD could decrease TNF-αlevel, it possibly reduced the inhibition action of TNF-αto insulin signal transduction.4 GSPD could cut down MDA level,increased SOD level and ameliorated the oxidative stress.5 GSPD could down regulating the expression of AT1R, and the effect of improving insulin resistance might be implementd by obstructing RAS, its decompression is possibly relevant to reducing the expression of AT1R in aorta and cardiac muscle of spontaneous hypertension rats. |
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