OBJECTIVETo compare the retinal function and retinal vascular pathologies in C57BL/6 and eNOS-knockout (eNOS(-/-)) mouse models of type 1 diabetes mellitus (T1DM) induced by streptozotocin (STZ).

METHODST1DM models were established in 6- to 8-week-old C57BL/6 and eNOS(-/-) mice by intraperitoneal STZ injection. Electroretinogram (ERG) examination, fluorescein angiography (FFA), immunofluorescence staining and retinal ganglion cell counts were carried out before and after STZ injection.

RESULTSDiabetic C57BL/6 and eNOS(-/-) mice showed significantly lowered a-wave and b-wave amplitude in ERG and reduced number of retinal ganglion cells (P<0.05), and the retinal vessels in diabetic eNOS(-/-) mice became tortuous. Compared with diabetic C57BL/6 mice, diabetic eNOS(-/-) mice showed more severe pathological changes in retinal function and retinal vessels with also more rapid onset of pathologies.

CONCLUSIONCompared with C57BL/6 mouse models, eNOS(-/-) mouse models of T1DM can better represent the occurrence and development of diabetic retinopathy, thus providing an ideal model for diabetes and diabetic retinopathy studies.

Animals ; Diabetes Mellitus, Experimental ; complications ; pathology ; Diabetes Mellitus, Type 1 ; complications ; pathology ; Diabetic Retinopathy ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Nitric Oxide Synthase Type III ; genetics ; Retinal Ganglion Cells ; pathology

OBJECTIVETo investigate the relationship between apoptosis and the expression of Bcl-2 and Bax in the penis cavernosal tissues of diabetic rats.

METHODSFifty male adult Wistar rats were divided into two groups: 10 as normal control and 40 used to induce diabetes by intravenous injection of alloxan (AXN) (50 mg/kg). After 8 weeks, their penises were harvested. Apoptosis was evaluated by means of terminal deoxynucleotidyl transferase mediated d-UTP nick end labeling (TUNEL). Immunohistochemistry was employed to detect the protein of Bcl-2 and Bax.

RESULTSCompared with those in the control group, apoptotic cells were more in number (P<0.01) and the expression of Bcl-2 was absent in the penis cavernosal tissues of the diabetic rats. However, there was upregulation of Bax and decrease in Bcl-2/Bax ratio in the diabetic group.

CONCLUSIONThe high rate of apoptosis in diabetic rats may play a role in the pathophysiology of erectile dysfunction. The change in Bcl-2 and Bax activities may be responsible for apoptosis in diabetic penis erectile tissues.

Animals ; Apoptosis ; DNA, Neoplasm ; genetics ; Diabetes Mellitus, Experimental ; metabolism ; pathology ; Disease Models, Animal ; Gene Expression ; Male ; Penis ; metabolism ; pathology ; Proto-Oncogene Proteins c-bcl-2 ; biosynthesis ; genetics ; Rats ; Rats, Wistar ; bcl-2-Associated X Protein ; biosynthesis ; genetics

OBJECTIVETo explore the characteristics of cell apoptosis and proliferation of corpus cavernosum smooth muscle (CCSM) cells in diabetic rats.

METHODSFrom a SD rat model of diabetes induced by a single dose of streptozotocin, CCSM cells were isolated for primary culture and identified using immunocytochemical assays for SMα-actin. The proliferation of CCSM cells was evaluated by WST-1 assay, and flow cytometry was used to detect the cells apoptosis. Real-time fluorescence quantitative RT-PCR (qRT-PCR) was used to analyze the relative expression of proliferation cell nucleus antigen (PCNA) and caspase-3 mRNA.

RESULTSThe proliferation rate of the primarily cultured CCSM cells from diabetic rats was significantly decreased and the apoptosis rate significantly increased compared with those of the cells from the control rats. The expression of PCNA mRNA was significantly lowered while caspase-3 mRNA significantly increased in the corpus cavernosum of the diabetic rats (P<0.001).

CONCLUSIONIn rats with persisted hyperglycemia, a higher apoptosis rate and a lower proliferation rate both contribute to the reduction of CCSM cells.

Animals ; Apoptosis ; physiology ; Cell Proliferation ; Diabetes Mellitus, Experimental ; pathology ; Male ; Myocytes, Smooth Muscle ; pathology ; Penis ; cytology ; physiopathology ; Primary Cell Culture ; Proliferating Cell Nuclear Antigen ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley

AIMTo study the effect of angiotensin-(1-7) on the kidney of diabetic rats by observing the mRNA expression of PDGF and TGF-beta1.

METHODSSD rats were divided into three groups: Group C (uni-nephrectomy control group), Group D (diabetic model control group), Group T (Ang-(1-7) treated group). We evaluated blood glucose,urea nitrogen, creatinine and urine albumin excretion respectively, studied the renal morphology by light microscope, and detected the gene expression of PDGF, TGF-beta1 in renal tissue by RT-PCR technique.

RESULTSThere was significant difference between the group D and T about the RW/BW, renal morphology, the total urine protein and the mRNA expression of PDGF and TGF-beta1.

CONCLUSIONAng-(1-7) can relieve the renal process of diabetic rats.

Angiotensin I ; pharmacology ; Animals ; Diabetes Mellitus, Experimental ; metabolism ; Diabetic Nephropathies ; metabolism ; Kidney ; metabolism ; pathology ; Male ; Peptide Fragments ; pharmacology ; Platelet-Derived Growth Factor ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Transforming Growth Factor beta1 ; genetics ; metabolism

The aim of the present study was to evaluate the protective effect of catalpol on vascular endothelial function in STZ-induced type 2 diabetes mellitus (T2DM) rats. 40 high-fat diet with STZ-induced diabetes rats were randomly divided into model group, catalpol low-dose, middle-dose and high-dose group (10, 50, 100 mg x kg(-1) x d(-1)), 10 normal Wistar rats were used as the normal group. The normal and model groups were given an equivalent amount of saline. All reagents were administered by oral gavage for 6 weeks. After 6 weeks, blood glucose and lipids were detected by an automatic biochemical analyzer. The endothelium-dependent vasodilation response of thoracic aortar was detected. The pathological changes of the thoracic aorta were observed by HE staining. Ser- um nitric oxide (NO), 8-iso prostaglandin F2α (8-iso-PGF2α) and superoxide dismutase (SOD) were detected by ELISA. Reactive oxygen species (ROS) level of thoracic aorta was detected by fluorescence method. The expression of Nox4 and p22phox mRNA and protein in aortic tissue were detected by RT-PCR and Western-blot respectively. After catalpol treatment, endothelial damage of thoracic aorta was attenuated significantly; ROS level of thoracic aorta and serum level of 8-iso-PGF2α were decreased significantly; serum NO and SOD levels were remarkably elevated; expression of Nox4, p22phox mRNA and protein in thoracic aorta were significantly reduced (P < 0.05). Therefore, catalpol has protective effect on endothelial of T2DM, its mechanism may be associated with the down-regulation of Nox4 and p22phox expression, inhibiting oxidative stress reaction response.
Animals ; Blood Glucose ; metabolism ; Diabetes Mellitus, Experimental ; pathology ; Diabetes Mellitus, Type 2 ; pathology ; Dinoprost ; analogs & derivatives ; metabolism ; Endothelium, Vascular ; drug effects ; metabolism ; pathology ; Enzyme Inhibitors ; pharmacology ; Gene Expression Regulation ; drug effects ; Iridoid Glucosides ; pharmacology ; Male ; NADPH Oxidase 4 ; NADPH Oxidases ; antagonists & inhibitors ; genetics ; metabolism ; Nitric Oxide ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Wistar ; Reactive Oxygen Species ; metabolism ; Superoxide Dismutase ; metabolism

This study examined the potential roles of astragalus and angiotensin II type 2 receptor (AT2) in rats with streptozotocin (STZ)-induced diabetic cardiomyopathy. Of 52 female 4-week-old Wistar rats treated with high glucose and lipid diet to induce insulin resistance, 7 treated with sodium citrate buffer (pH=4.5) served as controls (con1) and the other 45 were treated by intraperitoneal injection (ip) of STZ to induce type 2 diabetes. After 20 weeks, the maximal velocity decrease of pressure per second in left ventricle within the period of isovolumic relaxation (-dp/dtmax) was detected by inserting cannula through right carotid artery. Of the 45 rats, 24 with -dp/dtmax < or = 700 mmHg/s (1 mmHg=0.133 kPa) developing diabetic cardiomyopathy were grouped as follows: 7 treated with double distilled H2O (ip) were included in control group 2 (con2); other 8 treated with AT2 agonist (CGP42112A, ip) were included in experimental group1 (exp); 9 treated with astragalus (po) constituted experimental group 2 (exp2). All injections lasted 4 weeks (qd) and the heart weight (HW) was recorded. Cardiomyocyte apoptosis index (CAI), mRNA of AT2 and Bcl-2 as well as AT2 and Bcl-2 protein values in cardiomyocytes were also measured. Our results showed that -dp/dtmax in exp1, exp2 and con2 were much lower than those in con1 (P<0.01). CAI and AT2 in both mRNA and protein in con1 were lower than those in the other three groups (P<0.01). The three parameters above were higher in exp1 but less in exp2 than those in con2, respectively (P<0.01). The three parameters and HW in exp1 were much higher than those in exp2 (P<0.01). Changes of Bcl-2 were opposite to those of AT2. Our results suggested that high expression of AT2 might accelerate the apoptosis of cardiomyocytes in diabetic rats and play an important role in precipitating diabetic cardiomyopathy and astragalus protects diabetic rats from developing cardiomyopathy by downregulating AT2.
Animals ; Apoptosis ; drug effects ; Astragalus membranaceus ; chemistry ; Cardiomyopathies ; etiology ; pathology ; prevention & control ; Diabetes Mellitus, Experimental ; complications ; metabolism ; Down-Regulation ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Female ; Myocytes, Cardiac ; pathology ; Phytotherapy ; Rats ; Rats, Wistar ; Receptor, Angiotensin, Type 2 ; biosynthesis ; genetics

OBJECTIVETo investigate the ultrastructure of myocardium and gene expression of calcium handling proteins in diabetic rat heart.

METHODSDiabetes was induced in male Sprague-Dawley rats by a single injection of alloxanm (40 mg/kg ) and the rats in control group were injected with normal saline. At the end of 2, 4, 6 weeks after the induction of diabetes, the animals were sacrificed. The expression of calcium handling proteins was detected by reverse transcription-polymerase chain reaction (RT-PCR) and actin mRNA was used as internal standard. Heart tissue at the apex was obtained for light and electron microscope study.

RESULTSAt the end of 4 and 6 weeks, cardiosomatic ratio of diabetic rats was higher than that of control. Electron microscopy revealed a spectrum of subcellular remodeling in myocardium which was characterized by damaged myofibrils and mitochondria, dilated and swollen sarcoplasmic reticulum. Expression of phospholamban mRNAs was significantly increased, but 1,4,5-trisphosphate inositol receptor type 2, ryanodine receptor type 2 mRNAs were significantly decreased compared with those in the age-matched control rats. In contrast, the expression of sarco/endoplasmic reticulum Ca(2+)-ATPase mRNAs was not affected.

CONCLUSIONIn diabetic rat heart, gene expression of calcium handling proteins was characterized by up-regulation of phospholamban and down-regulation of sarcoplasmic reticulum calcium release channel while electron microscopic analysis of myocardium revealed a spectrum of subcellular remodeling.

Animals ; Calcium ; metabolism ; Calcium Channels ; metabolism ; Calcium-Binding Proteins ; biosynthesis ; genetics ; metabolism ; Diabetes Mellitus, Experimental ; metabolism ; pathology ; Endoplasmic Reticulum ; metabolism ; ultrastructure ; Male ; Myocardium ; metabolism ; ultrastructure ; RNA, Messenger ; biosynthesis ; genetics ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Sarcoplasmic Reticulum ; metabolism ; ultrastructure

OBJECTIVE: To evaluate the effect of hepatic insulin gene therapy on diabetic enteric neuropathy. METHODS: Mice were randomly allocated into 3 groups: a normal control group, a diabetic group, and a diabetic gene therapy group. Diabetes were induced by penial vein injection of streptozocin (STZ). The gene therapy group received hepatic insulin gene therapy while the other 2 groups only received an empty virus expressing green fluorescent protein. Random blood glucose, body weight growth, gastric emptying, total bowel length, absolute and relative bowel transit, electric field stimulation of colon smooth muscle, colon nuclei staining and counting were measured. RESULTS: We successully established a mouse model of diabetic enteric neuropathy which manifests as: 8 weeks of continuous hyperglycemia,increased total bowel length, decreased relative bowel transit, impaired colon smooth muscle relaxation and loss of inhibitory neurons in colon. Through gene therapy, the above indexes were normalized or ameliorated, suggesting hepatic insulin gene therapy is capable of preventing diabetic enteric neuropathy. CONCLUSION Hepatic insulin gene therapy can prevent STZ induced diabetic enteric neuropathy.
Adenoviridae ; Animals ; Diabetes Mellitus, Experimental ; complications ; therapy ; Diabetic Neuropathies ; therapy ; Enteric Nervous System ; metabolism ; pathology ; Gastrointestinal Diseases ; etiology ; therapy ; Gene Transfer Techniques ; Genetic Therapy ; Genetic Vectors ; Hepatocytes ; metabolism ; Insulin ; genetics ; metabolism ; Mice ; Proinsulin ; genetics

The aim of this study is to investigate the therapeutic effect of RegIII-proinsulin-pBudCE4.1 plasmid on streptozotocin (STZ)-induced type 1 diabetes mellitus and its underlying mechanisms. The model of type 1 diabetes mellitus was established by intraperitoneal injections of STZ (40 mg kg(-1)) to Balb/c mice for five consecutive days. Then, ten type 1 diabetic mice were intramuscularly injected with 100 microg RegIII-proinsulin-pBudCE4.1 plasmid for 4 weeks (one time/week) and the blood glucose levels were monitored every week; whereas another ten diabetic mice served as negative control group were injected with pBudCE4.1 vector at the same dose. Normal control and model control mice were treated with normal saline at identical volume under the same way. Western blotting, MTT assay, ELISA, HE staining and Tunel assay were applied to explore the underlying mechanisms. Results showed that RegIII-proinsulin-pBudCE4.1 plasmid ameliorated the hyperglycemia symptoms in diabetic mouse remarkably. It induced an immunological tolerance state in type 1 diabetic mice by inhibiting the proliferation of splenic lymphocytes and recovering Th1/Th2 balance evidenced by MTT and ELISA analysis. Furthermore, it elevated insulin concentration in the serum of type 1 diabetic mice and promoted the regeneration of beta cells supported by the results of HE staining and Tunel assay. In conclusion, RegIII-proinsulin-pBudCE4.1 plasmid possesses powerful anti-diabetic ability, which may be involved in the inducing of immunological tolerance and enhancing beta cells recovery.
Animals ; Apoptosis ; Blood Glucose ; metabolism ; Cell Proliferation ; Diabetes Mellitus, Experimental ; metabolism ; pathology ; therapy ; Diabetes Mellitus, Type 1 ; chemically induced ; metabolism ; pathology ; therapy ; Genetic Therapy ; Hyperglycemia ; therapy ; Injections, Intramuscular ; Insulin ; blood ; Islets of Langerhans ; cytology ; Male ; Mice ; Mice, Inbred BALB C ; Plasmids ; Proinsulin ; genetics ; metabolism ; therapeutic use ; Proteins ; genetics ; metabolism ; therapeutic use ; Streptozocin ; T-Lymphocytes ; cytology ; Th1-Th2 Balance

BACKGROUNDThe most intimidatory pathological changes in patients with DM are cardiovascular illnesses, which are the major causes of death in diabetic patients and are far more prevalent than in nondiabetics because of accelerated atherosclerosis. In this study, we tried to clarify the changes in macrovascular endothelial ultrastructure and in the gene expression of endothelial nitric oxide synthase (eNOS)mRNA in diabetic rats.

METHODSThe study was conducted on 52 of 10-week old Sprague Dawley (SD) rats with body weight of (320 +/- 42) g. SD rats were divided into: experimental group treated with a single intraperitoneal injection of streptozotocin (STZ, 60 mg/kg), (male, n = 20, diabetes mellitus (DMM)); female, n = 12, diabetes mellitus female (DMF)) and control group (male, n = 10, diabetes mellitus male control (DMMC); female, n = 10, diabetes mellitus female control (DMFC)). Four weeks after treatment, half of the rats were sacrificed; the remainders were sacrificed ten weeks after treatment. One part of the abdominal aortic sample was stored under glutaraldehyde (volume fraction psiB = 2.5%). After the process of chemical fixation, chemical dehydration, drying and conductivity enhancement, all samples were observed and photographed using scanning electron microscopy (Leica-Stereoscan 260, England). The other part of the abdominal aortic sample was treated with liquid nitrogen and the expression of eNOSmRNA was assessed by semi-quantitative RT-PCR.

RESULTSThe aortic lumen of both experimental groups adsorbed much more debris than that of either control group. The endothelial surfaces of diabetic rats were coarse, wrinkled and protuberant like fingers or villi. The vascular endothelial lesions of diabetic male rats were very distinct after 4 weeks, and as obvious as those at 10 weeks. The vascular endothelial lesions of diabetic female rats were not severe at 4 weeks and only became marked after 10 weeks. In both males and females, the abdominal aortic eNOSmRNA content of 4 weeks and 10 weeks diabetic rats was very significantly lower (P < 0.01) than that of controls.

CONCLUSIONSAortic endothelial ultrastructure in DM rats is injured compared with controls. Abnormal changes of aortic endothelia in male DM rats are more obvious than those in females. Expression of abdominal aortic eNOSmRNA content of DM rats is significantly lower than that of controls.

Animals ; Aorta, Abdominal ; enzymology ; Blood Glucose ; analysis ; Diabetes Mellitus, Experimental ; enzymology ; pathology ; Endothelium, Vascular ; ultrastructure ; Female ; Male ; Nitric Oxide Synthase ; genetics ; Nitric Oxide Synthase Type III ; RNA, Messenger ; blood ; Rats ; Rats, Sprague-Dawley ; Sex Factors ; Streptozocin