OBJECTIVETo understand the influence of accumulation of advanced glycosylation end products (AGE) on wound healing of burn rats complicated with diabetes.

METHODSSeventy-five SD rats were divided into control, diabetes, and aminoguanidine-interfered groups in completely randomized method, with 25 rats in each group. All rats were subjected to deep partial-thickness scald. Diabetes was reproduced in rats of diabetes and aminoguanidine-interfered groups. Rats in aminoguanidine-interfered group were fed with 100 mg x kg(-1) xd (-1) aminoguanidine. Rats were sacrificed on post-scald day (PSD) 0, 3, 7, 14, and 21, and portrait of the wounds were taken. Full-thickness skin tissue specimens were obtained for determination. Specimens of epidermis from back of SD rats were obtained for KC cultivation and verification. Wound healing rate, glucose content in skin tissue, morphologic change in wound tissue, AGE distribution in skin tissue, influence of AGE on proliferation and apoptosis of KC were observed.

RESULTSWound healing rate of rats was respectively lower in diabetes group than that in control group on PSD 7, 14, and 21 (P < 0.01), but it was obviously higher in aminoguanidine-interfered group than that in the former 2 groups (P < 0.01). Glucose content of rat skin in diabetes group was (2.62 +/- 0.19) mmol/g, and it was (2.58 +/- 0.07) mmol/g in aminoguanidine-interfered group, both higher than that in control group [(1.04 +/- 0.09) mmol/g, P < 0.01]. In control group, limited intensive infiltration of inflammatory cells was found in the wound with necrotic tissue formation which fell off in time, and with no obvious delay of wound healing. In diabetes group, infiltration of inflammatory cells in wounds of rats appeared slowly, but diffusely and persistently; necrotic tissue formed and fell off late in time, with obvious delay of wound healing. In aminoguanidine-interfered group, intensive infiltration of inflammatory cells was observed in time, and the time of necrotic tissue formation and sloughing, and wound healing were respectively earlier than that in diabetes group. Sporadic disposition of small amount of AGE was found in rats in control group. AGE accumulation increased significantly in rats in diabetes group. AGE content decreased significantly in rats in aminoguanidine-interfered group after administration of aminoguanidine. KC proliferation decreased significantly in concentration dependent manner 48 hours after AGE stimulation. Absorbance value of AGE decreased in each AGE-interfered group (P < 0.01). Early Annexin-V positive apoptotic KC rate was obviously higher in 100 ug/mL AGE-interfered group (15.1 +/- 2.3)% than that in control group [(11.2 +/- 1.2)%, P < 0.05]. There was no statistical significance between 100 ug/mL AGE-interfered group (14.3 +/- 3.5)% and control group (15.2 +/- 2.4)% in respect of the rate of double-positive cells apoptosis at final stage (P > 0.05).

CONCLUSIONSHyperglycemia may inhibit proliferation of repairing cells such as KC through AGE accumulation, thus impedes wound healing. Reduction of AGE accumulation could ameliorate wound healing delay due to diabetes.

Animals ; Blood Glucose ; metabolism ; Burns ; complications ; metabolism ; Diabetes Mellitus, Experimental ; complications ; metabolism ; Glycation End Products, Advanced ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; Wound Healing

OBJECTIVEHyperglycemia could upregulate transforming growth factor-beta (TGFbeta(1)) via thrombospondin (TSP-1) and induce fibrotic renal disease in the rat in vivo and myocardial fibrosis was related to cardiac dysfunction in diabetic patients. We explored the role of glucose/TSP-1/TGFbeta(1) signal pathways in the development of diabetic cardiomyopathy (DCM).

METHODSMale Wistar rats were fed with high cholesterol diet for 17 weeks, streptozocin (30 mg/kg, i.p) was given at the 28th day, rats with fasting blood glucose > or = 11.1 mmol/L by the end of the 5th week were assigned to DCM group (n = 11). Control rats (n = 8) were fed with regular chow. Fasting blood glucose (FBG) was monitored throughout the study. After hemodynamic measurements by the end of the study, myocardial collagen content was quantified in Masson-stained samples and the mRNA expressions of TSP-1 and TGFbeta(1) were detected by quantification real-time RT-PCR. The protein levels of TSP-1, active and latent TGFbeta(1) were detected by Western blot.

RESULTSCompared with control group, cardiac function was decreased as shown by significantly reduced left ventricular systolic pressure, dp/dt(max) and dp/dt(min), while the myocardial collagen content was significantly increased in the DCM group (11.01 +/- 3.05 vs. 16.92 +/- 3.18, P < 0.01). The myocardial mRNA expressions of TSP-1, TGFbeta(1) and protein expressions of TSP-1, active and latent TGFbeta(1) in the DCM group were also significantly higher than those of the control group. Moreover, myocardial collagen was positively correlated to FBG (r = 0.746, P < 0.01); mRNA expressions of TSP-1 and TGFbeta(1), protein expressions of TSP-1 and active TGFbeta(1) were positively correlated to FBG and myocardial collagen (P < 0.05). However, there were no correlations between the protein expression of latent TGFbeta(1) and FBG and myocardial collagen.

CONCLUSIONThe pathway of glucose/TSP-1/TGFbeta(1) might play an important role in myocardial interstitial fibrosis of DCM. It may be the basis of novel therapeutic approaches for ameliorating DCM.

Animals ; Cardiomyopathies ; etiology ; metabolism ; Diabetes Mellitus, Experimental ; complications ; metabolism ; Glucose ; metabolism ; Male ; Myocardium ; metabolism ; Rats ; Rats, Wistar ; Signal Transduction ; Thrombospondin 1 ; metabolism ; Transforming Growth Factor beta1 ; metabolism

OBJECTIVETo investigate the role of the non-canonical Wnt signaling pathway in development of non-alcoholic steatohepatitis (NASH) related to type 2 diabetes mellitus (T2DM) using a rat model.

METHODSTwenty-four male Sprague-Dawley rats were randomly divided into two equal groups: control group, fed a stand diet; T2DM-NASH model group, fed a high sucrose and fat diet for 4 weeks and intraperitoneally injected with streptozotocin (30 mg/kg). Twelve weeks after model establishment, all rats were sacrificed. Serum levels of glucose, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were detected by biochemical analysis. Liver pathological changes were assessed microscopically by hematoxylin-eosin and oil red O staining. The liver expression of Wnt5a and NF-kB p65 were detected by immunohistochemistry and western blotting (protein), and quantitative real-time PCR (mRNA).

RESULTSThe T2DM-NASH model group showed significantly higher levels of glucose (control group: 6.25 +/- 1.28 vs. 31.21 +/- 0.86 mmol/L, t = -36.204, P less than 0.01), ALT (31.00 +/- 3.69 vs. 301.50 +/- 8.62 U/L, t = -99.94, P less than 0.01), and AST (77.58 +/- 1.83 vs. 344.75 +/- 1.82 U/L, t = -358.85, P less than 0.01). The T2DM-NASH group also showed remarkable signs of steatosis and inflammation in hepatic tissues. The T2DM-NASH group had significantly higher integral optical density (IOD) detection of Wnt5a (control group: 1.15E4 +/- 577.45 vs. 4.04E5 +/- 2.42E4, t = -56.24, P less than 0.01) and NF-kB p65 (1.28E4 +/- 1.59E3 vs. 4.21E5 +/- 1.68E4, t = -83.895, P less than 0.01), as well as protein levels detected by western blot (Wnt5a: 4.21 +/- 0.34 vs. 1.00 +/- 0.25, t = 17.030, P less than 0.01; NF-kB p65: 4.93 +/- 0.76 vs. 1 +/- 0.13, t = 11.438, P less than 0.01). The hepatic mRNA levels followed the same trend (Wnt5a: 9.53 +/- 0.64 vs. 1.04 +/- 0.35, t = 20.165, P less than 0.01; NF-kB p65: 0.60 +/- 0.13 vs. 0.74 +/- 0.10, t = -1.802, P = 0.125). In the T2DM-NASH group, hepatic Wnt5a protein expression was positively correlated with ALT (r = 0.64, P less than 0.05), AST (r = 0.59, P less than 0.05), and NF-kB p65 protein expression (r = 0.58, P less than 0.05).

CONCLUSIONWnt5a may activate NF-kB to stimulate an inflammatory response leading to development of NASH related to T2DM.

Animals ; Diabetes Mellitus, Experimental ; complications ; metabolism ; Diabetes Mellitus, Type 2 ; complications ; metabolism ; Liver ; pathology ; Male ; Non-alcoholic Fatty Liver Disease ; etiology ; pathology ; Rats ; Rats, Sprague-Dawley ; Transcription Factor RelA ; metabolism ; Wnt Proteins ; metabolism ; Wnt Signaling Pathway ; Wnt-5a Protein

OBJECTIVETo observe the role of activation of aldehyde dehydrogenase 2 (ALDH2) on myocardial ischemia/reperfusion (I/ R) injury in diabetic rats.

METHODSDiabetic rat model was simulated by intraperitoneal injection 55 mg/kg streptozotocin (STZ) and divided into diabetes and ethanol + diabetes groups (n = 8). After 8 weeks, myocardial ischemia/reperfusion model was mimicked in vitro. The ventricular dynamical parameters and lactate dehydrogenase (LDH) content in coronary flow were determined. The fasting blood glucose and glycosylated hemoglobin (HbA1c) level were determined by automatic biochemistry analyzer. The ALDH2 mRNA and protein expressions of left anterior myocardium were evaluated by RT-PCR and Western blot.

RESULTSIn contrast to I/R in normal rat, in diabetic rat, left ventricular development pressure (LVDP), maximal rise/fall rate of left ventricular pressure (+/- dp/dtmax) and left ventricular work (RPP) were decreased, left ventricular end diastolic pressure (LVEDP) and LDH release were increased, and ALDH2 mRNA and protein expressions were decreased; compared with I/R in diabetic rat, ALDH2 agonist ethanol significantly promoted the recovery of LVDP, +/- dp/dtmax, RPP, reduced HbA1c level, LVEDP and LDH released, ALDH2 mRNA and protein expressions were increased.

CONCLUSIONIn diabetic rat, the expression of ALDH2 was decreased when heart was subjected to I/R. Enhanced mitochondrial ALDH2 expression in diabetic rat could play cardiac protective role.

Aldehyde Dehydrogenase ; metabolism ; Aldehyde Dehydrogenase, Mitochondrial ; Animals ; Diabetes Mellitus, Experimental ; complications ; metabolism ; Male ; Mitochondrial Proteins ; metabolism ; Myocardial Reperfusion Injury ; etiology ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the role of miR-145 in the corpus cavernosum smooth muscle tissue in the pathogenesis of erectile dysfunction (ED) in diabetic rats.

METHODSThe total RNA was extracted from the corpus cavernosum of a diabetic rat model with ED, diabetic rats with normal erectile function and normal rats, and the expression levels of miR145 were compared between the groups.

RESULTSThe expression of miR-145 was decreased in the corpus cavernosum of diabetic rats with ED.

CONCLUSIONDiabetes mellitus can cause ED in rats, in which process decreased expression of miR145 in the corpus cavernosum may play a role.

Animals ; Diabetes Mellitus, Experimental ; complications ; metabolism ; physiopathology ; Erectile Dysfunction ; etiology ; metabolism ; physiopathology ; Male ; MicroRNAs ; genetics ; metabolism ; Muscle, Smooth ; metabolism ; Penile Erection ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo observe the dynamic expression of calcium-sensing receptor(CaSR) in myocardium of diabetic rats.

METHODSThirty male Wistar rats were randomly divided into 3 groups including control, diabetic-4 week and diabetic-8 week groups(n = 10). The type 2 diabetes mellitus models were established by intraperitoneal injection of streptozotocin (STZ, 30 mg/kg) after high-fat and high-sugar diet for one month. The cardiac morphology was observed by electron microscope. Western blot analyzed the expression of CaSR, phospholamban (PLN), a calcium handling regulator, and Ca+-ATPase(SERCA) in cardiac tissues.

RESULTSCompared with control group, the expressions of CaSR and SERCA were decreased, while the expression of PLN was significantly increased in a time-dependent manner in diabetic groups. Meanwhile diabetic rats displayed abnormal cardiac structure.

CONCLUSIONThese results indicate that the CaSR expression of myocardium is reduced in the progression of DCM, and its potential mechanism may be related to the imnaired intracellular calcium homeostasis.

Animals ; Calcium-Binding Proteins ; metabolism ; Diabetes Mellitus, Experimental ; complications ; Diabetes Mellitus, Type 2 ; Diabetic Cardiomyopathies ; metabolism ; physiopathology ; Disease Progression ; Heart ; physiopathology ; Male ; Myocardium ; metabolism ; pathology ; Rats ; Rats, Wistar ; Receptors, Calcium-Sensing ; metabolism ; Sarcoplasmic Reticulum Calcium-Transporting ATPases ; metabolism ; Streptozocin

Along with the development of economy and society, type 2 diabetic mellitus (T2DM) has become one of the most common diseases at the global level. As one of the complications of T2DM, diabetic neuropathic pain (DNP) stubbornly and chronically affects the health and life of human beings. In the pain field, dorsal root ganglion (DRG) is generally considered as the first stage of the sensory pathway where the hyperexcitability of injured neurons is associated with different kinds of peripheral neuropathic pains. The abnormal electrophysiology is mainly due to the changed properties of voltage-gated sodium channels (VGSCs) and the increased sodium currents (I(Na)). Curcumin is an active ingredient extracted from turmeric and has been demonstrated to ameliorate T2DM and its various complications including DNP effectively. The present study demonstrates that the I(Na) of small-sized DRG neurons are significantly increased with the abnormal electrophysiological characteristics of VGSCs in type 2 diabetic neuropathic pain rats. And these abnormalities can be ameliorated efficaciously by a period of treatment with curcumin.
Animals ; Curcumin ; pharmacology ; Diabetes Mellitus, Experimental ; complications ; Diabetes Mellitus, Type 2 ; complications ; Diabetic Neuropathies ; drug therapy ; Ganglia, Spinal ; cytology ; drug effects ; metabolism ; Neuralgia ; drug therapy ; Neurons ; drug effects ; metabolism ; Rats ; Sodium ; Voltage-Gated Sodium Channels ; physiology

Diabetes is the most common cause of erectile dysfunction (ED). Oxidative stress has been suggested to be a contributory factor in vascular complications of diabetes in various organs. In the present study, we investigated whether oxidative stress is associated with erectile function in non- insulin dependant diabetes mellitus (NIDDM) rats. Fifty-four Sprague-Dawley rats were the subjects of this study. In each rat, NIDDM was induced by an intraperitoneal injection of 90mg/Kg of streptozotocin on the second day after birth. Based on the diabetic period, they were classified into either short-term or long-term diabetics (avg. 22 weeks, n=18 and avg. 38 weeks, n=20), respectively, and their age-matched controls (n=16). To evaluate the erectile function in each rat, the intracavernous pressure, and latency to maximal pressure, following cavernous nerve stimulation (frequency: 1 Hz, intensity: 3 - 6 V, pulse width: 1 msec, pulse duration: 1 min.) was analyzed. To evaluate both oxidative stress from reactive oxygen species, and antioxidant function as a defense against them, total malondialdehyde and glutathione levels were measured in the corpus cavernosum of the penis, using a spectrophotometric assay. The intracavernous pressure following cavernous nerve stimulation was significantly lower in the long-term (49.8 +/- 9.4 cmH2O) than the short-term diabetics (75.9 +/- 14.8 cm H2O), and markedly decreased in the diabetic rats, compared with their age-matched controls (long-term controls; 60.7 +/- 17.2 cmH2O, short-term controls; 95.2 +/- 20.4 cmH2O). The malondialdehyde content in the corpus cavernosum was markedly increased in the diabetics (2.13 +/- 0.27 nM/mg protein) compared to the controls (1.48 +/- 0.22 nM/mg protein). Furthermore, the glutathione level was significantly decreased in the diabetics, compared to age-matched controls (short-term control; 218.3 +/- 25.6 microM/mg protein, long-term control; 150.2 +/- 9.8 microM/mg protein). In the diabetic groups, it was more significantly decreased in the long-term diabetics (134.8 +/- 11.3 microM/mg protein) than in short-term diabetics (182.1 +/- 18.8 microM/mg protein). NIDDM causes erectile dysfunction, which slowly progresses. Oxidative stress to cavernous tissue may be a contributory factor in erectile dysfunction in diabetics.
Animals ; Diabetes Mellitus, Experimental/*complications/metabolism ; Diabetes Mellitus, Type II/*complications ; Female ; *Free Radicals ; Glutathione/analysis ; Impotence/*etiology ; Lipid Peroxidation ; Male ; Rats ; Rats, Sprague-Dawley ; Streptozocin ; Support, Non-U.S. Gov't

OBJECTIVE: To investigate the effect of diet-induced hyperlipidemia on TGF-beta/Smad signaling pathway in the kidney of diabetic rats, and to explore the mechanism by which hyperlipidemia leads to renal injury in diabetes. METHODS: Diabetic rats and non-diabetic rats were fed with normal fat diet and high fat diet for 16 weeks, respectively. The expressions of TGF-beta1, TbetaRII, and Col-IV mRNA in the renal cortex were examined by reverse transcriptase-PCR,TbetaRII and p-Smad staining in glomerular cells were detected by immunohistochemical staining, and the expression of TGF-beta1 and Col-IV protein was determined by Western blot. RESULTS: Diet-induced hyperlipidemia up-regulated the levels of TGF-beta1, TbetaRII, p-Smad, and Col-IV protein and mRNA in the renal cortex of diabetic rats compared with those of non-diabetic rats. However, feeding high fat diet to non-diabetic rats had no influence on the expression of TGF-beta1, TbetaRII, p-Smad2, and Col-IV in the renal cortex. CONCLUSION Hyperlipidemia induced by high fat diet ingestion leads to renal injury in diabetic rats through activating TGF-beta1 /Smad signaling pathway.
Animals ; Diabetes Mellitus, Experimental ; complications ; metabolism ; Diabetic Nephropathies ; metabolism ; Dietary Fats ; administration & dosage ; Female ; Hyperlipidemias ; complications ; metabolism ; Kidney ; metabolism ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Smad Proteins ; metabolism ; Transforming Growth Factor beta1 ; metabolism

BACKGROUNDAdrenomedullin is a potent vasodilating peptide and involved in many cardiovascular diseases. However, whether adrenomedullin is involved in the pathogenesis of diabetic cardiomyopathy is still unknown. Our aim was to characterize the expression pattern of adrenomedullin in the myocardium of streptozotocin-induced diabetic rats.

METHODSThe weight, blood glucose, and urine glucose of 20 streptozotocin-induced diabetic rats were measured before and after model induction in the diabetic and control groups. The alteration of the adrenomedullin expression was explored in the left ventricular myocardium in both groups by immunohistochemistry. Changes in heart ultrastructure were also analyzed by using hemotoxylin and eosin staining and transmission electron microscopy. All data were analyzed by the independent samples t test.

RESULTSThe data of weight, blood glucose, and urine glucose had no significant difference between the control and the diabetic groups before animal model induction. Four weeks after the induction of diabetes, the differences between the two groups in weight, blood glucose, and urine glucose were distinct. When compared with the control group, the diabetic group showed ultrastructural changes including hypertrophy, fibrosis, myofibrillar disarrangements, mitochondrial disruption, and increase in nuclear membrane invaginations. A significant decrease of adrenomedullin expression was also observed in cardiac myocytes of the diabetic rats (P < 0.01).

CONCLUSIONSOur study provides experimental evidence that hyperglycemia could damage cardiac myocytes. Down-regulation of cardioprotective peptide adrenomedullin in the myocardium of streptozotocin-induced diabetic rats may contribute to the diabetic cardiomyopathy and left ventricular dysfunction.

Adrenomedullin ; analysis ; Animals ; Blood Glucose ; analysis ; Cardiomyopathies ; etiology ; Diabetes Mellitus, Experimental ; complications ; metabolism ; Female ; Immunohistochemistry ; Myocardium ; chemistry ; ultrastructure ; Rats ; Rats, Sprague-Dawley ; Streptozocin