Relationship between the E-selectin and oxidative stress in patients with obese type 2 diabetes mellitus

AIM: To investigate the relationship between the levels of soluble E-selectin and oxidative stress in patients with obese type 2 diabetes mellitus.METHODS: The level of E-selectin, the contents of ox-LDL and malondialdehyde (MDA) and activities of superoxide dismutase (SOD) were measured in patients with obese and non-obese type 2 diabetes mellitus.RESULTS: The levels of E-selectin, ox-LDL and MDA were higher in patients with obese type 2 diabetes mellitus than those in control group (P<0.05), and the contents of HDL-C, HDL2-C and HDL3-C were significantly lower than those in control group (P<0.01).The activity of SOD in patients with obese type 2 diabetes mellitus was significantly lower than that in control group.The contents of E-selectin and MDA were more markedly elevated in patients with obese type 2 diabetes mellitus than those in patients with non-obese type 2 diabetes mellitus (P<0.01,P<0.05) and the activity of SOD was also significantly lower than that in patients with non-obese type 2 diabetes mellitus (P<0.01).There was significantly positive correlation between E-selectin and HbA1c, waist circumference, TC, ox-LDL, MDA (r=0.352, P<0.05;r=0.634, P<0.05;r=0.517, P<0.05;r=0.480, P<0.05;r=0.572, P<0.05), and negatively correlation between E-selectin and HDL3-C (r=-0.374, P<0.05).CONCLUSION: The plasma level of E-selectin is markedly elevated in patients with obese type 2 diabetes mellitus.E-selectin is possibly associated with oxidative stress.     

Measurement and analysis of microcirculation dysfunction in type 2 diabetic patients

AIM: To measure microcirculation function in type 2 diabetic patients and non-diabetic subjects with a new measurement method called capillary recruitment. METHODS: 276 type 2 diabetic patients in Shanghai downtown were enrolled and categorized into several groups, those with diabetes duration <5 years，5-10 years or ≥10 years, those with body mass index ≥25 kg/m2 or <25 kg/m2 and those with or without family history of diabetes. We determined skin capillary recruitment after arterial occlusion with capillaroscopy and compared the percentage increase of capillary density among these groups. 20 non-diabetic subjects were also measured.RESULTS: The average age of non-diabetic subjects was (60.56±6.73) years old. The average baseline capillary density was (36.25±8.78)/mm2, with an average peak capillary density of (48.97±10.24)/mm2. The average age of diabetic patients was (64.94±10.72) years old. The average baseline capillary density was (33.65±9.78)/mm2, with an average peak capillary density of (42.70±11.74)/mm2.The diabetes duration increased, as did the percent increase of capillary density ［(29.63%±13.85%)， (27.45%±12.23%)， (25.75%±10.90%), respectively］. The percentage increase of those with diabetes family history or body mass index ≥25 kg/m2 was significantly decreased in comparison with controls. There was no significant difference in the percent increase of capillary density between genders.CONCLUSION: We have evaluated the microcirculation function in type 2 diabetic patients and the results show a close relation between dysfunction of microcirculation and obesity, diabetes family history and diabetes duration.     

Changes of the first-phase insulin secretion in first-degree relatives of type 2 diabetic subjects with different glucose-tolerance

AIM: To investigate the role of the insulin secretion as well as insulin sensitivity in the onset and development of the type 2 diabetes mellitus (T2DM). METHODS: This study included 38 normal glucose tolerance(NGT) subjects without family history of diabetes, 32 NGT and 36 impaired glucose tolerance(IGT) subjects who were the first-degree relatives of type 2 diabetes, and 35 newly-diagnosed type 2 diabetic patients.β cell function and insulin sensitivity were examined by using oral glucose-insulin release test (OG-IRT) with SIM reflecting insulin sensitivity and intravenous glucose tolerance test (IVGTT) with AIR3-5 reflecting the first-phase insulin secretion function. AIR3-5 was calculated as the average incremental plasma insulin concentration from the third to the fifth minute after the glucose bolus. AIR3-5 and SIM were compared among the four groups. RESULTS: From NGT, IGT to type 2 diabetes,there was a decreasing tendency of the level of AIR3-5 and SIM with NGT the highest, IGT the medium and T2DM the lowest. The level of the AIR3-5 in the subjects of NGT who were first-degree relatives of type 2 diabetes were lower than those of NGT without family history of diabetes（P<0.01）, while there was no significant difference in the SIM level between the two groups（P>0.05）. CONCLUSION: Insulin secretion dysfunction may be the primary factor in the onset of type 2 diabetes. Along with the developing of IGT and type 2 diabetes, the insulin secretion and sensitivity decrease.     

Changes of matrix metalloproteinase-3 and urokinase-type plasminogen activator receptor in type 2 diabetes mellitus with macroangiopathy

AIM: To investigate the function of matrix metalloproteinase-3 (MMP-3) and urokinase-type plasminogen activator receptor (uPAR) to macroangiopathy in type 2 diabetes mellitus. METHODS: The levels of MMP-3 and uPAR in plasma were determined by ELISA sandwich method in 26 healthy controls and 39 patients with type 2 diabetes mellitus including 15 complication-free cases and 24 with macroangiopathy. RESULTS: The plasma level of uPAR but not MMP-3 was higher in patients without macroangiopathy than that in normal controls (P<0.05). In patients with macroangiopathy, the plasma levels of MMP-3 and uPAR were higher than those in normal controls (P<0.01) and patients without angiopathy. There was positive relationship between MMP-3 and uPAR in type 2 diabetes mellitus (r=0.405, P<0.05), and LDL-C was the important affecting factor of uPAR. CONCLUSION: MMP-3 and uPAR are associated with the development of macroangiopathy in type 2 diabetes mellitus. MMP-3 can be regarded as the circulatory markers in type 2 diabetes mellitus with macroangiopathy.     

Relationship between levels of plasma endothelin-1/serum nitric oxide and hearing impairment in type 2 diabetes

AIM: To evaluate the relationship between endothelin-1 (ET-1)/nitric oxide (NO) and hearing impairment in type 2 diabetes mellitus (DM).METHODS: Eighty-eight type 2 diabetic patients with no signs of microangiopathy (retinopathy and nephropathy) or peripheral neuropathy, and 53 healthy subjects in the same period were enrolled in this study. Auditory function was evaluated using pure tone audiometry. Totally,type 2 DM group (n=88) and normal control group (NC, n=53) were divided into subgroups based on the presence and absence of hearing impairment. The concentration of plasma ET-1 was detected by radioimmunoassay. The concentration of serum NO was measured by the method of nitric acid reductase.RESULTS: Significantly increased plasma ET-1 and decreased serum NO were observed in diabetic patients with hearing impairment compared with those in diabetic patients without hearing impairment. The results of multivariate logistic regression analysis showed that hearing impairment in type 2 DM group was significantly associated with elevated level of HbA1c (OR＝4.525, P<0.05), LDL-C (OR=2.381,P<0.05) and plasma ET-1 (OR＝6.207,P<0.01). Besides, elevated serum level of NO (OR＝0.862, P<0.05) was associated with lower risk of hearing impairment in diabetics.CONCLUSION: Hearing impairment may happen earlier than other complications in diabetic patients. In addition to hyperglycemia and hyperlipemia, high level of ET-1 and low levels of NO might contribute to hearing impairment in diabetic patients.     

Influence of 8-week swimming on peripheral neuropathy in type 2 diabetic rats

AIM: To explore the influence of long-term swimming on peripheral neuropathy in type 2 diabetic rats. METHODS: Male Wistar rats were fed with a high-fat and high-fructose diet, and injected with streptozocin to establish a model of type 2 diabetes mellitus. The rats were randomly divided into 4 groups: blank control group (C group), exercise control group (CE group), diabetes mellitus group (DM group) and diabetes mellitus+exercise group (DME group). The rats in CE group and DME group received 8-week swimming training (6 d/week). The training time was 20, 30 and 45 min in the first 3 d,respectively, and then it increased to 60 min a day. Eight weeks later, the motor nerve conduction velocity (MNCV) and the levels of tumor necrosis factor α (TNF-α), interleukin 6 (IL-6) and C-reactive protein (CRP) in sciatic nerve tissues of the rats were measured. The morphological changes of the sciatic nerve were also observed under light microscope. RESULTS: Compared with DM group, 8-week swimming obviously accelerated the MNCV (P<0.05), decreased the levels of TNF-α, IL-6 and CRP in DME group (but no significant difference, P>0.05). The obvious nerve injury in DM group was observed. However, the pathological change of the sciatic nerve in DME group was relieved. CONCLUSION: Eight-week swimming training significantly accelerates the MNCV, attenuates the nerve injury in diabetic rats and has protective effect on peripheral nerve, which may be correlated with relieving the inflammatory reaction.     

Changes of heart function and serum cardiac troponin I in early type 2 diabetic rats

AIM: To observe the changes of heart function and the expression of serum cardiac troponin I(cTnI) in early type 2 diabetic rats, and to explore the role of cTnI in the development of type 2 diabetes and early diabetic cardiomyopathy.METHODS: The type 2 diabetes rat model was established by an injection of streptozotocin after high fat diet(5 weeks). The rats were randomly divided into control group, model group of 2 weeks, and model group of 4 weeks. M-mode echocardiography was performed for echocardiographic measurements. Fasting blood glucose(FBG), total cholesterol(TC), triglyceride(TG), high density lipoprotein-cholesterol(HDL-C), low density lipoprotein- cholesterol(LDL-C), fasting insulin(FINS) and cTnI levels were tested. HE staining was used to observe the pathological changes of myocardial structures. The alteration of cTnI in myocardium was determined by Western blot.RESULTS: Compared with normal group, the levels of TC, TG and LDL-C in type 2 diabetic rats were significantly increased, HDL-C levels were significantly reduced. Cardiac histological analysis revealed that type 2 diabetes induced cardiomyocytes degeneration and necrosis. The expression of cTnI increased significantly in diabetic groups compared to control group, and that in model group of 4 weeks increased far more than that in model group of 2 weeks(P<0.05).CONCLUSION: The increased level of cTnI and the change of the heart function may be associated with the development diabetic cardiomyopathy. These changes are valuable for the early clinical diagnosis of myocardial injury in diabetic cardiomyopathy.     

Effect of pentoxifylline on caspases expression in islet beta-cells of NOD mice

AIM: To investigate the intervention effect of pentoxifylline (PTX) on type 1 diabetes mellitus in non-obese diabetic (NOD)mice and explore its possible mechanism.METHODS: Eight-week-old NOD mice were treated with PTX to investigate the incidence of cyclophosphamide accelerating diabetes.The apoptosis of beta-cells was detected by TUNEL,the expressions of caspase-3 in islet of the NOD mice was checked by immunohistochemistry and the expressions of caspase-8 was determined by RT-PCR.RESULTS: The incidence of diabetes in PTX group was 40.63%,which was obviously lower than 69.70% in the control group (P<0.05). Apoptosis index of beta-cells was 4.80% in PTX group and was 9.04% in control group,of which the former was lower than the latter (P<0.01).The expression of caspase-3 in islet of the mice in PTX group was much lower than that in control group,and the expression of caspase-8 mRNA in pancreas in PTX group were also markedly lower than that in control group (P<0.01).CONCLUSION: PTX prevents NOD mice from developing type 1 diabetes,which may be related to the downregulation of caspase-3 and caspase-8 expressions in pancreas and then the decrease of beta-cell apoptosis.     

Protective role of carnosine on cardiac dysfunction in type 1 diabetes mellitus rat model

AIM:To explore the effects of carnosine (CAR) on cardiac dysfunction in type 1 diabetic mellitus rats and the underlying mechanism. METHODS:The SD rats were randomly divided into 4 groups:control (C) group, control+carnosine (C+CAR) group, diabetes mellitus (DM) group and diabetes mellitus+carnosine (DM+CAR) group (n=10). The rats were sacrificed after 12 weeks. The cardiac function was assessed by ventricular cannulation. The activity of superoxide dismutase (SOD) and the content of malondialdehyde (MDA) were assessed by ELISA. The mRNA levels of tumor necrosis factor α(TNF-α), interleukin-1β(IL-1β) and IL-6 were measured by real-time PCR. The distribution of connexin 43 (Cx43) was examined by immunofluorescence. The protein levels of Cx43 and protein kinase C (PKC) were determined by Western blot. RESULTS:Compared with the C group, the left ventricular end diastolic pressure (LVEDP) was increased whereas the left ventricular pressure maximum rise/fall velocity (±dp/dt_max) was decreased in the DM group (P<0.01). The activity of SOD decreased while the MDA increased in the left ventricular tissues (P<0.01). The mRNA levels of TNF-α, IL-1β and IL-6 were increased (P<0.01). The Cx43 distribution was irregular. The protein levels of phosphorylated Cx43 and PKCε were elevated (P<0.01). Compared with the DM group, the cardiac function of LVEDP and ±dp/dt_max in DM+CAR group was ameliorated (P<0.01), with increased SOD activity and decreased MDA content (P<0.05). The mRNA levels of TNF-α, IL-1β and IL-6 were reduced (P<0.01). The Cx43 distribution was improved and the protein levels of phosphorylated Cx43 and PKCε were decreased (P<0.01). CONCLUSION:CAR treatment can improve the cardiac function by its anti-oxidative and anti-inflammation effects and suppression of Cx43 abnormalities through PKCε in DM rats.     

The association of paraoxonase 2 gene 311Cys/Ser polymorphism and type 2 diabetes mellitus complicated by coronary heart disease

AIM:To study the association of the human paraoxonase 2(PON2)311Cys/Ser polymorphism genotypes and coronary heart disease(CHD)in type 2 diabetes mellitus(type 2 DM)in Chinese subjects of north area. METHODS:PON2-311 cysteine(C type)/serine(S type)polymorphism was determined using PCR and restriction mapping with Dde Ⅰ,in 75 elder pat ients with type 2 DM,39 with CHD,36 without CHD,and 38 normal elder controls.RESULTS:There was significant difference in frequencies of genotypes between CHD in type 2 DM group and normal control group(P<0.05).S allele frequencies of PON2-311Cys/Ser polymorphism in CHD in type 2 DM group were higher than that in control groups.The S allele of PON2-311Cys/Ser was a risk for developing CHD in type 2 DM(OR=2.09,95%CI:1.04-4.22,P<0.05).CONCLUSION:The S allele of PON2-311Cys/Ser polymorphism is associated with CHD in type 2 DM.The dif erence of PON2-311Cys/Ser among various races was observed.     

Influence of obesity on first-phase insulin secretion in individuals with different glucose tolerance

AIM: To explore the influence of obesity on the first-phase insulin secretion in the individuals with different glucose tolerance. METHODS: Thirty-eight subjects with normal glucose tolerance without family history of diabetes (normal control,NC), 32 subjects with normal glucose tolerance (NGT) who were the first-degree relatives of type 2 diabetic patients, 67 patients with impaired glucose regulation (IGR) and 35 newly-diagnosed type 2 diabetic patients (T2DM) were enrolled in the study. The patients in the 4 groups were further divided into 2 subgroups: overweight/obesity and normal weight subgroups. All subjects received oral glucose-insulin release test (OG-IRT) and intravenous glucose tolerance test (IVGTT). Acute insulin response at 3~5 min (AIR3-5) was used to reflect first-phase insulin secretion,and insulin sensitivity index (ISI) was used to reflect insulin sensitivity. The influence of obesity on the islet β-cell function and insulin sensitivity in the individuals with different glucose tolerance was observed. RESULTS: The level of AIR3-5 in NC overweight/obesity subgroup was significantly higher than that in normal weight subgroup (P<0.05), while there was no significant difference between other subgroups (P>0.05). No significant difference in the level of ISI between the patients of IGR in overweight/obesity subgroup and normal weight subgroup was observed, while in the other 3 overweight/obesity subgroups, ISI was lower than that in normal weight subgroups (P<0.05). ISI was negatively correlated with body mass index and waist circumference in all groups (P<0.05). ISI was also positively correlated with AIR3-5 in NC group and negatively correlated in the other 3 groups (P<0.05). CONCLUSION: The impact of obesity on insulin secretion is not the same in the subjects with different glucose tolerance. With the aggravation of insulin resistance, the first-phase insulin secretion in the subjects with normal glucose tolerance without family history of diabetes increases for compensation, while that in the normal glucose tolerance subjects who are the first-degree relatives of type 2 diabetic patients, the patients with impaired glucose regulation and the type 2 diabetic patients could not increase for compensation.     

mRNA expression of insulin receptor and leptin receptor in liver of nonalcoholic fatty liver disease from diabetic rats

AIM: To observe the pathologic changes of liver in diabetic rats and to investigate the role of mRNA expression of insulin receptor and leptin receptor in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). METHODS: Twenty male Sprague-Dawley rats were divided randomly into two groups: normal control group and diabetic group. After fed with high-fat diet for 4 weeks, diabetic rats were injected with streptozotocin at a dosage of 30 mg/kg intraperitoneally to induce NAFLD model of type 2 diabetes mellitus. Then the diabetic animals were fed with high-fat diet continuously for 12 weeks. At the end of the experiment, the rats were sacrificed, the concentrations of blood glucose, serum lipid, ALT and AST were measured biochemically. The levels of serum leptin and serum insulin were detected by enzyme-linked immunosorbent assay (ELISA) and radio immunoassay (RIA), respectively. The pathologic changes of liver were observed under light microscopy (LM) stained with HE, Sudan Ⅲ and Masson trichrome staining, respectively. The ultra-structural changes of liver were observed under transmission electron microscopy (TEM). Additionally, the mRNA expressions of PEPCK, G6Pase, insulin R and leptin R from rat livers were assayed by semi-quantitative RT-PCR. RESULTS: The levels of blood glucose, serum insulin, serum TG, ALT and AST increased significantly (P<0.01), serum TC elevated (P<0.05), and the levels of serum leptin decreased (P<0.01) in diabetic group compared to those in normal control group. Obvious liver fatty degeneration, piecemeal necrosis with accompanying inflammatory infiltration and fibrosis were found under LM. Hepatocytes pyknosis, lots of lipid deposits in cytoplasm of hepatocytes, proliferation of collagen in space of Disse were observed under TEM in diabetic group. The expression of insulin R and leptin R mRNA in liver from diabetic rats increased significantly (P<0.01) while the expression of PEPCK and G6Pase mRNA remained unchanged. CONCLUSION: Insulin resistance plays an important role in the pathogenesis of NAFLD. Low level of serum leptin, up-regulation of mRNA expression of insulin R and leptin R in liver caused by insulin resistance may be involved in this process.     

Effect of curcumin derivative B06 on liver from type 2 diabetic rats

AIM:To observe the protective effect of curcumin derivative B06 on the liver from the rats with hyperlipidemia and type 2 diabetes mellitus. METHODS:Male Sprague-Dawley rats (n=35) were divided randomly into 5 groups: normal control group, high-fat group, high-fat+B06-treated group, diabetic group and diabetic +B06-treated group. After fed with a high-fat diet for 4 weeks, the rats in the later 2 groups were injected with streptozotocin intraperitoneally to induce type 2 diabetes mellitus. The rats in B06-treated groups were given B06 by gavage at a dose of 0.2 mg· kg-1·d-1 for 8 weeks. After the treatment, the morphology of the liver was observed under light and transmission electron microscopes. The protein expression of AMP-activated protein kinase α (AMPKα) and phosphorylated AMPK α (p-AMPKα) was detected by Western blotting. RESULTS:Fatty degeneration, hepatocellular necrosis, inflammatory cell infiltration and hyperplasia of fibrous tissue were observed in the liver from the rats in high-fat group and diabetic group,and were relieved after B06 treatment. The protein expression of p-AMPKα was decreased in the liver of the rats in diabetic group and high-fat group, and it was increased in the liver of the high-fat and diabetic rats in B06-treated group. CONCLUSION:Curcumin derivative B06 exerts a protective effect on the liver in type 2 diabetic rats, and the increased expression of p-AMPKα may be involved in the mechanism of protection.     

Effect of sitagliptin on cardiomyocyte pyroptosis induced by type 2 diabetes mellitus and underlying mechanism

AIM: To explore the effect of sitagliptin (SLT) on cardiomyocyte pyroptosis induced by type 2 diabetes mellitus (T2DM) and the underlying mechanism. METHODS: The T2DM rat model was established by high-fat diet and intraperitoneal injection of streptozotocin (35 mg/kg). The model rats were treated with SLT at 3, 10 and 30 mg/kg and nicotinamide[NAM; an non-specific inhibitor of sirtuin (SIRT) family] at 500 mg/kg for 4 weeks. Fasting blood glucose was measured, and the tissue proteins were determined by the methods of Western blot and immunochemistry. RESULTS: Compared with control group, the pyroptosis of cardiomyocytes and NLRP3 expression were significantly induced, while the protein level of SIRT3 was downregulated by T2DM (P<0.05). SLT inhibited the pyrpotosis of diabetic rat cardiomyocytes, downregulated the expression of NLRP3, and upregulated the expression of SIRT3 in a dose-dependent manner (P<0.05). All the function of SLT (30 mg/kg) was reversed by the treatment with NAM (500 mg/kg). Compared with control group, the pyroptosis of cardiomyocytes and NLRP3 expression were significantly induced, while the protein level of SIRT3 was not regulated by NAM (500 mg/kg). CONCLUSION: SLT exerts the inhibitory effect on the pyroptosis of cardiomyocytes induced by diabetes, and the mechanism is related to the SIRT3/NLRP3 signaling pathway.     

Changes of cardiac function,RAGE expression and calcium dysregulation in type 2 diabetic rats

AIM: To investigate the changes of cardiac structure and function in rats with type 2 diabetic mellitus (T2DM), and to explore the mechanisms underlying diabetic cardiomyopathy. METHODS: The cardiac structure and function were measured by echocardiography in Zucker diabetic fatty (ZDF) rats and their control Zucker lean (ZL) rats. The size of the cardiomyocytes was determined by wheat germ agglutinin staining. The protein expression of atrial natriuretic peptide (ANP), β-myosin heavy chain (β-MHC), receptor for advanced glycation end products (RAGE), L-type cal-cium channel α1C subunit (Ca_V1.2) and Orai1 was assessed by Western blot. RESULTS: Compared with the ZL control rats, the thickness of left ventricular wall, ejection fraction (EF), fractional shortening (FS) and the sizes of cardiomyocytes were significantly increased, and diastolic function was decreased in the ZDF rats (P<0.05). The protein expression of β-MHC, ANP, RAGE and Orai1 was increased, while the expression of Ca_V1.2 was decreased in ZDF rats (P<0.05). CONCLUSION: T2DM rats show the prominent features including cardiomyocyte hypertrophy, ventricular hypertrophy and compensatory enhancement of cardiac function, and the Ca²⁺ handling and increase in RAGE expression may play important roles in the processes.     

Study of lung morphologic features and oxygen free radicals in experimental diabetic rats

AIM:To evaluate the changes of lung morphologic features and oxidative stress in experimental diabetic rats. METHODS: The pulmonary structure of alloxan-induced diabetic rats were quantitatively studied with stereological methods. Changes of ultrastructure, activities of superoxide dismutase (SOD) and contents of malondialdehyde(MDA) of diabetic lung and serum were observed. RESULTS: The volume proportion of alveolar air and mean linear intercept of diabetic rats decreased remarkably in comparison with controls while the volume proportion of alveolar wall, the surface density of alveolar, the numerical density of alveolic area, the numerical density of alveolar and specific surface of alveolar increased significantly. The major change of the type II pneumocyte of diabetic rats was dilation of the rough endoplasmic reticulum (RER). The other findings in diabetic rats had included the presence of thickened alveolar epithelial, pulmonary capillary basal laminae and blood- air barrier, the volume density, the surface density, the mean profile area and the mean perimeter of RER in type Ⅱ pneumocyte of diabetic rats increased remarkably. And the specific surface of RER was significantly lower as compared with controls. SOD activity decreased and MDA content increased significantly in serum of diabetic rats as compared with the control group. SOD activity in the diabetic lung was not different from that of the control lung. However, the content of MDA obviously increased in diabetic lung. CONCLUSION: The morphologic features and oxidative stress in early diabetic rats are abnormal thus the lung should be considered as one of the "target organ"in diabetes mellitus.     

Relationship between 936C/T polymorphism in 3’-untranslated region of vascular endothelial growth factor gene and diabetic retinopathy in China

AIM: To study the distribution of 936C/T polymorphism in 3’- untranslated region of vascular endothelial growth factor (VEGF) gene in Chinese Han population and to analyze the relationship between the polymorphism and diabetic retinopathy (DR). METHODS: Two hundred and fifty-four patients with type 2 diabetes mellitus recruited in this study were divided into NPDR group (non-proliferative diabetic retinopathy), PDR group (proliferative diabetic retinopathy) and DM (diabetes without retinopathy) group. The normal control group consisted of 120 subjects. Genotypes were identified by PCR-RFLP among all the subjects, while other clinical parameters were measured. Serum levels of VEGF were tested by the method of ELISA. RESULTS: The frequencies of both genotype CC and allele C were significantly higher in NPDR group and PDR group than those in NC group (²=9.934, ²=4.899, P<0.05 and ²=10.895, ²=5.714, P<0.05) and DM group (²=7.490, ²=4.448, P<0.05 and ²=8.333, ²=5.227, P<0.05). However, the frequencies of genotype (TT+CT) and allele T were significantly lower in NPDR group and PDR group than those in NC group (²=9.934, ²=10.895, P<0.01 and ²=4.899, ²=5.714, P<0.05) and DM group (²=7.490, ²=8.333, P<0.01 and ²=4.448, ²=5.227, P<0.05). Multivariate logistic regression analysis showed that the levels of glycohemoglobin(HbA1c), total cholesterol(TC),low-density lipoprotein cholesterol(LDL-C) and plasma VEGF presented a positive correlation with DR, respectively, and the 936C/T mutation of VEGF exhibited a negative correlation with DR (β=-1.027, OR=0.343, P<0.01, CI: 0.157-0.723). CONCLUSION: Allele 936C of VEGF may be a genetic marker susceptible to DR, while allele 936T may be a protective genetic marker of DR. The 936C/T mutation of VEGF may be a protective factor against DR.     

Dynamic expression of S-adenosyl-L-homocysteine hydrolase under intervention of fimasartan in early stage of type 2 diabetic cardiomyopathy rats

AIM: To detect the changes of S-adenosyl-L-homocysteine hydrolase (SAHH) signaling pathway and related proteins under the intervention of fimasartan (FIM) in rats with diabetes mellitus (DM), and to explore the pathological mechanism of the occurrence and development of diabetic cardiomyopathy (DCM). METHODS: The type 2 diabetic rat model was established by injection of streptozocin after 5-week high-fat diet. The rats were randomly divided into control group, DM group, and DM+FIM group. Fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and fasting insulin (FINS) levels were tested. M-mode echocardiography was performed for determining the heart functions. High-performance liquid chromatography (HPLC) was used to detect homocysteine (Hcy), S-adenosylmethionine (SAM) and S-adenosyl-L-homocysteine (SAH). The alteration of SAHH in myocardium was determined by Western blot. RESULTS: The success rate of type 2 diabetic rat modeling was 84%. Compared with DM group, the body weight of the rats in DM+FIM group increased significantly (P<0.05), while cardiac index, left ventricular index, FBG and LDL-C were significantly reduced (P<0.05). The results of echocardiography showed that ejection fraction increased (P<0.05) in DM+FIM group. HPLC detection showed that the level of Hcy and the ratio of SAM/SAH were significantly reduced (P<0.05). The results of Western blot showed that the expression of SAHH in DM group was increased compared with control group, while that in DM+FIM group declined (P<0.01). CONCLUSION: The expression of SAHH, Hcy and other related factors may be important during the occurrence and development of early DCM, and FIM may play a role in this process as an inhibitor of SAHH.     

Expression of FBXW7 in diabetic cardiomyopathy

AIM:To investigate the expression of F-box/WD repeat-containing protein 7 (FBXW7) in the myocardium of type 1 diabetic rats and to clarify its role in the development of diabetic cardiomyopathy. METHODS:All rats were randomly divided into non-diabetic (ND) group, 4-week diabetes mellitus (DM) model group, 8-week DM mo-del group and 12-week DM model group. The DM model was prepared by intraperitoneal injection of streptozotocin (60 mg/kg). The change of myocardial pathological structure was investigated by HE staining. The FBXW7 expression level in the myocardium was determined by Western blot and immunohistochemistry methods. RESULTS:DM induced cardiomyocyte degeneration and necrosis as shown by cardiac histological analysis. Both Western blot and immunohistochemistry results showed that the expression level of FBXW7 was significantly increased in 4-week, 8-week and 12-week DM groups compared with control group (P<0.01). However, The FBXW7 expression level in 12-week DM group was decreased compared with 4-week and 8-week DM groups. CONCLUSION:With the development of diabetes, the expression of FBXW7 in the myocardium of the rats with diabetic cardiomyopathy shows a tendency to increase first and then decrease, suggesting that it plays some roles in the development of diabetic cardiomyopathy.     

Changes of adiponectin and adiponectin receptor 1 in diabetic rats of different courses during myocardial ischemic preconditioning

AIM: To investigate the different effects of adiponectin (APN) and adiponectin receptor 1 (Ad-R1) on myocardial ischemia-reperfusion (IR) injury and ischemic preconditioning (IPC) in different course of diabetic rats in vitro. METHODS: The rat models of type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) were successfully established using streptozotocin and high-fat diet plus streptozotocin, respectively. These rats were divided into 2 groups:4 weeks and 8 weeks. The model of isolated cardiac perfusion was established by Langendorff method. Each group was further divided into control (Con) group, IR group and IPC group. The activity of lactate dehydrogenase (LDH) and creatine kinase (CK) in coronary effluent was detected. The serum and myocardial levels of APN were determined by ELISA. The expression of Ad-R1 in the myocardial tissues was detected by Western blot. The area of myocardial infarction was detected, and the ultrastructure of ventricular papillary muscle was observed by transmission electron microscopy. RESULTS: Compared with the corresponding IR group, the activity of LDH and CK in the IPC group at 4 weeks was significantly decreased (P<0.01), and the area of myocardial infarction was significantly reduced. However, no significant difference of each index in DM groups at 8 weeks was observed. Serum APN level was decreased in diabetic rats, especially in T2DM rats (P<0.05). The levels of APN and Ad-R1 in myocardium of normal rats had no difference among Con, IR and IPC groups. The level of APN in myocardium of T1DM rats had no difference in all subgroups, while the expression of Ad-R1 in myocardial tissue of IR group was significantly increased as compared with Con group (P<0.01) and IPC group (P<0.01) both at 4 and 8 weeks. In T2DM rats, the levels of APN in myocardium both at 4 and 8 weeks were decreased in IR group compared with Con group (P<0.05). The level of APN in IR group at 4 weeks was significantly decreased compared with IPC group, but had no significant difference at 8 weeks. The expression of Ad-R1 in myocardial tissue of IR group was significantly increased compared with Con group (P<0.05) both at 4 and 8 weeks. The level of Ad-R1 in IR group at 4 weeks was significantly increased compared with IPC group (P<0.05), but had no significant difference at 8 weeks. CONCLUSION: The protective effect of IPC exists in diabetic rats at 4 weeks, whereas it disappears at 8 weeks. APN and Ad-R1 in myocardium were probably involved in the protective effect of IPC on T2DM rats.