Chronic bronchial dilatations in different colonies of laboratory rats

Bronchiectasis occurred naturally in 12-month-old spontaneously diabetic eSS male rats. The lungs of 3 and 6-month-old eSS rats were compared in eumetabolic eSS rats from three inbred lines consisting of inbred spontaneously diabetic eSS derived from IIM strain; these were compared with eumetabolic, outbred Wistar rats, paired by sex and age. Acrylic casts of bronchial tree were obtained after injection of a plastic substance. The casts were pruned to focus on the first four bronchial branchings. Diameter and volume of the conductive bronchial tree were determined using a binocular magnifier. Histological sections were obtained. All lines showed multiple bronchiectasis, mostly fusiform, bronchial dilatation and inflammatory response with lymphocytic infiltrates. These symptoms were much more severe in 180-day-old eSS males. Bacteria were isolated from the lungs in 70% of cases (n = 32), except in eSS rats. Pseudomonas spp. (38%) and Gram-positive cocci as coagulase-negative Staphylococcus spp. (20%) were detected. Neither pathogenic bacteria nor saprophyte fungi were found. Although all lines were affected, diabetes in eSS appears to be an aggravating factor.     

Melatonin and taurine reduce early glomerulopathy in diabetic rats

Oxidative stress occurs in diabetic patients and experimental models of diabetes. We examined whether two antioxidants, melatonin and taurine, can ameliorate diabetic nephropathy. Enhanced expression of glomerular TGF-beta1 and fibronectin mRNAs and proteinuria were employed as indices of diabetic nephropathy. Experimental diabetes was induced by intravenous injection of streptozotocin 50 mg/kg. Two days after streptozotocin, diabetic rats were assigned to one of the following groups: i) untreated; ii) melatonin supplement by 0.02% in drinking water; or iii) taurine supplement by 1% in drinking water. Four weeks after streptozotocin, diabetic rats (n = 6: plasma glucose 516+/-12 mg/dl) exhibited 6.1 fold increase in urinary protein excretion, 1.4 fold increase in glomerular TGF-beta1 mRNA, 1.7 fold increase in glomerular fibronectin mRNA, 2.2 fold increase in plasma lipid peroxides (LPO), and 44 fold increase in urinary LPO excretion above the values in control rats (n = 6: plasma glucose 188+/-14 mg/dl). Chronic administration of melatonin (n = 6) and taurine (n = 6) prevented increases in glomerular TGF-beta1 and fibronectin mRNAs and proteinuria without having effect on blood glucose. Both treatments reduced lipid peroxidation by nearly 50%. The present data demonstrate beneficial effects of melatonin and taurine on early changes in diabetic kidney and suggest that diabetic nephropathy associated with hyperglycemia is largely mediated by oxidative stress.     

Role of 12-lipoxygenase in decreasing P-cadherin and increasing angiotensin II type 1 receptor expression according to glomerular size in type 2 diabetic rats

12-lipoxygenase (12-LO) was implicated in the development of diabetic nephropathy (DN), in which the proteinuria was thought to be associated with a decreased expression of glomerular P-cadherin. Therefore, we investigated the role of 12-LO in the glomerular P-cadherin expression in type 2 diabetic rats according to the glomerular sizes. Rats fed with high-fat diet for 6 wk were treated with low-dose streptozotocin. Once diabetes onset, diabetic rats were treated with 12-LO inhibitor cinnamyl-3,4-dihydroxy-cyanocinnamate (CDC) for 8 wk. Then glomeruli were isolated from diabetic and control rats with a sieving method. RT-PCR, Western blotting, and immunofluorescent staining were used for mRNA and protein expressions of P-cadherin and angiotensin II (Ang II) type 1 receptor (AT1). We found that CDC did not affect the glucose levels but completely attenuated diabetic increases in glomerular volume and proteinuria. Diabetes significantly decreased the P-cadherin mRNA and protein expressions and increased the AT1 mRNA and protein expressions in the glomeruli. These changes were significantly prevented by CDC and recaptured by direct infusion of 12-LO product [12(S)-HETE] to normal rats for 7 days. The decreased P-cadherin expression was similar between large and small glomeruli, but the increased AT1 expression was significantly higher in the large than in the small glomeruli from diabetic and 12(S)-HETE-treated rats. Direct infusion of normal rats with Ang II for 14 days also significantly decreased the glomerular P-cadherin expression. These results suggest that diabetic proteinuria is mediated by the activation of 12-LO pathway that is partially attributed to the decreased glomerular P-cadherin expression.     

Contrasting effects of early and late orchiectomy on hypertension and renal disease in fawn-hooded rats

Fawn-hooded (FH) rats, primarily males, develop spontaneous low-renin hypertension associated with reduced urinary excretion of kallikrein as early as 2 months of age, followed by progressive glomerular sclerosis and proteinuria as early as 3 months of age. In the present study we determined the effects of early (5-7 weeks) or late (5 months) orchiectomy on the blood pressure and nephropathy of FH rats, compared to sham-operated (control) FH males. Early orchiectomy reduced significantly the progression of glomerular sclerosis and of proteinuria and ameliorated the hypertension but had no significant effect on excretion of urinary kallikrein. Late orchiectomy, in contrast, had no significant effect on the progression of glomerular sclerosis or proteinuria but did significantly reduce the blood pressure and marginally increase the excretion of urine kallikrein. These results suggest that (a) male sex hormones may play a role in the pathogenesis of hypertension and nephropathy in the FH rats and (b) renal disease in this strain progresses in spite of improvement in blood pressure.     

Influence of intrauterine growth restriction on renal function in the adult rat

Intrauterine growth restriction (IUGR) has been shown to influence renal development and lead to fewer nephrons. Data on long term renal function after IUGR are limited. We studied the effect on renal function of IUGR in aging rats. IUGR was induced using a model of bilateral uterine artery ligation in pregnant Wistar rats. Renal function was studied at the age of 18 months. In male IUGR rats, estimated glomerular filtration rate was significantly decreased compared to male control rats [1.1 (SD 0.3) 1.7 (SD 0.3) ml x min(-1), p<0.05]. Female IUGR rats showed an increased urinary protein excretion compared with female control rats [84 (SD 73) vs. 12 (SD 13) mg x 24h(-1), p<0.01]. All male rats showed heavy proteinuria (p<0.01 vs. female rats from same experimental group), with no significant differences between the groups. Tubular reabsorption of phosphorus was lower in females, but showed no differences between the experimental groups. In conclusion, IUGR impairs renal function in the rat. It is suggested that a low nephron endowment leads to proteinuria as a sign of glomerular damage, and ends with a decrease in glomerular filtration rate as a sign of glomerular loss.     

Enalapril improves albuminuria by preventing glomerular loss of heparan sulfate in diabetic rats

Angiotensin converting enzyme (ACE) inhibitors, particularly enalapril and captopril, have been shown to decrease proteinuria in diabetic animals and human subjects. Since heparan sulfate proteoglycan confers a negative charge on the glomerular basement membrane, and either decreased synthesis or loss of this charge causes albuminuria in diabetic animals, we examined the possibility that enalapril prevents albuminuria through glomerular preservation of heparan sulfate in long-term diabetic rats. A total of 22 male Wistar rats were used in the study. Diabetes was induced in 15 rats by a single intraperitoneal injection of streptozotocin (60 mg/kg). The remaining 7 rats received buffer. One week following induction of diabetes, 8 diabetic rats were allowed to drink tap water containing enalapril at a concentration of 50 mg/liter; the remaining 7 diabetic and 7 nondiabetic rats were given only tap water. The drug treatment was continued for 20 weeks. Systolic blood pressure and 24-hr urinary excretion of albumin were measured at 2, 8, 16, and 20 weeks. At the end of 20 weeks, all rats were killed, kidneys were removed, and glomeruli were isolated by differential sieving technique. Total glycosaminoglycan and heparan sulfate synthesis was determined by incubating glomeruli in the presence of [35S]sulfate. Characterization of heparan sulfate was performed by ion-exchange chromatography. Systolic blood pressures were significantly lower in enalapril-treated diabetic rats compared to untreated diabetic rats. Diabetic glomeruli synthesized less heparan sulfate than glomeruli from nondiabetic rats. Also, glomerular heparan sulfate content of diabetics was significantly lower than that of nondiabetics. Further characterization of heparan sulfate showed that the fraction eluted with 1 M NaCl was significantly lower and the fraction eluted with 1.25 M NaCl significantly higher in diabetic than in normal rats. Enalapril treatment normalized not only glomerular synthesis and content but also various fractions of heparan sulfate in diabetic rats. Diabetic rats excreted increased quantities of heparan sulfate and albumin than nondiabetic rats. Enalapril therapy prevented both these increases in diabetic rats. These data suggest that enalapril treatment improves albuminuria through preservation of glomerular heparan sulfate and prevention of its urinary loss in diabetic rats.     

STZ诱导糖尿病肾病大鼠模型的建立

目的建立糖尿病大鼠动物模型,探讨其肾脏损害规律。方法用STZ65mg/kg一次性腹腔内注射方式制作糖尿病大鼠模型,设立空白对照组,饲养14周,期间观察大鼠血糖、尿糖及一般情况变化,实验结束时测定血肌酐、尿素氮、尿蛋白、尿白蛋白排泄率,取肾作病理及超微病理检查。结果模型组大鼠出现血肌酐、尿素氮、尿蛋白、尿白蛋白明显升高,出现肾脏肥大,病理显示明显的肾小球、肾小管病变。结论STZ诱导糖尿病大鼠肾脏表现肾小球及小管间质损害,可以用作糖尿病肾病研究的动物模型。     

Nephro-protective effect of granulocyte colony-stimulating factor in streptozotocin induced diabetic rats

Diabetic nephropathy is one of the most serious complications of diabetes and the major cause of end-stage renal failure. Consequences of diabetic nephropathy include increased kidney size and glomerular volume, thickening of basement membranes and progressive accumulation of extracellular matrix. Reports in the literature support an association between increased secretion of inflammatory molecules, such as cytokines, growth factors and metalloproteinases, and development of diabetic nephropathy. We investigated the potential of granulocyte colony- stimulating factor (G-CSF) as a therapeutic candidate for preventing diabetic nephropathy. We used 21 8-week-old male rats; 14 were administered a single dose of 60 mg/kg streptozotocin (STZ) to induce diabetes. The rats were divided into three groups of seven: group 1, control; group 2, diabetic; group 3, diabetic plus G-CSF treatment. After 4 weeks, immunoexpressions of transforming growth factor β1 (TGF-β1), Akt and CD34 levels were measured in the kidney tissue. Blood glucose, urine protein and the glomerular area also were measured for each group. We found that G-CSF treatment decreased TGF-β1 immunoexpression, urine protein and glomerular area in kidneys of diabetic rats, and increased CD 34 and Akt immunoexpression in kidneys of diabetic rats. The effects of G-CSF were independent of blood glucose levels. G-CSF may be a useful therapeutic agent for preventing diabetic nephropathy.     

Decrease in the Time-Dependent Difference in Urinary Excretion of Furosemide with Age

The influence of age on the time-dependent difference in urinary excretion of furosemide, a loop diuretic agent, was examined in this longitudinal study. Male Wistar rats were maintained under conditions of light from 07:00 to 19:00 h and dark from 19:00 to 07:00 h. Furosemide (30 mg/kg) was given orally at 12:00 h (day trial) or 00:00 h (night trial) to rats at 3 months of age, and urine was collected for 8 h after dosage. Thereafter, the identical protocol was repeated using the same animals at 6, 9, 12, 15, 18, and 21 months of age. The urinary excretion of furosemide was significantly greater in the day than in the night trial at 3 months of age. Such a time-dependent difference was observed for up to 15 months, but disappeared at 18 and 21 months of age. The time-dependent difference in urinary excretion of furosemide (day trial — night trial) decreased gradually throughout the observation period of the study. These results suggest that the time-dependent difference in the urinary excretion of furosemide diminishes during the aging process and disappears by 18 months of age in male Wistar rats.     

Resveratrol ameliorates early diabetic nephropathy associated with suppression of augmented TGF-β/smad and ERK1/2 signaling in streptozotocin-induced diabetic rats

Diabetic nephropathy (DN) is the major cause of end-stage renal disease. The early changes in DN are characterized by an increased in kidney size, glomerular volume, and kidney function, followed by the accumulation of glomerular extracellular matrix, increased urinary albumin excretion (UAE), glomerular sclerosis, and tubular fibrosis. Resveratrol (RSV) has been shown to ameliorate hyperglycemia and hyperlipidemia in streptozotocin-induced diabetic rats. In the present study, we examined the beneficial effects of RSV on DN and explored the possible mechanism of RSV action.Male Sprague–Dawley rats were injected with streptozotocin at 65 mg/kg body weight. The induction of diabetes mellitus (DM) was confirmed by a fasting plasma glucose level ≥300 mg/dL and symptoms of polyphagia and polydipsia. The DM rats were treated with or without RSV at 0.75 mg/kg body weight 3 times a day for 8 weeks. Animals were sacrificed and kidney histology was examined by microscopy. Urinary albumin excretion, glomerular hypertrophy and expressions of fibronectin, collagen IV, and TGF-β in the glomeruli were alleviated in RSV-treated DM rats, but not in untreated DM rats. In addition, RSV treatment reduced the thickness of the glomerular basement membrane (GBM) to the original thickness and increased nephrin expressions to normal levels in DM rats. Moreover, RSV inhibited phosphorylation of smad2, smad3 and ERK1/2 in diabetic rat kidneys. This is the first report showing that RSV alleviates early glomerulosclerosis in DN through TGF-β/smad and ERK1/2 inhibition. In addition, podocyte injuries of diabetic kidneys are lessened by RSV.     

The diabetic rat kidney mediates inosituria and selective urinary partitioning of D-chiro-inositol

Diabetic nephropathy is a serious complication of diabetes mellitus with a pressing need for effective metabolic markers to detect renal impairment. Of potential significance are the inositol compounds, myo-inositol (MI), and the less abundant stereoisomer, D-chiro-inositol (DCI), which are excreted at increased levels in the urine in diabetes mellitus, a phenomenon known as inosituria. There is also a selective urinary excretion of DCI compared to MI. As the biological origins of altered inositol metabolism in diabetes mellitus are unknown, the aim of this study was to determine whether the diabetic kidney was directly responsible. Kidneys isolated from four-week streptozotocin-induced diabetic rats were characterized by a 3-fold reduction in glomerular filtration rate (GFR) compared to matched non-diabetic kidneys. When perfused with fixed quantities of MI (50 µM) and DCI (5 µM) under normoglycemic conditions (5 mM glucose), GFR-normalized urinary excretion of MI was increased by 1.7-fold in diabetic vs. non-diabetic kidneys. By comparison, GFR-normalized urinary excretion of DCI was increased by 4-fold. Perfusion conditions replicating hyperglycemia (20 mM glucose) potentiated DCI but not MI urinary excretion in both non-diabetic and diabetic kidneys. Overall, there was a 2.4-fold increase in DCI urinary excretion compared to MI in diabetic kidneys that was independent of glucose ambience. This increased urinary excretion of DCI and MI in diabetic kidneys occurred despite increased renal expression of the inositol transporters, sodium myo-inositol transporter subtype 1 and 2 (SMIT1 and SMIT2). These findings show that the diabetic kidney primarily mediates inosituria and altered urinary partitioning of MI and DCI. Urinary inositol levels might therefore serve as an indicator of impaired renal function in diabetes mellitus with wider implications for monitoring chronic kidney disease.     

Anti-hyperglycemic activity of zinc plus cyclo (his-pro) in genetically diabetic Goto-Kakizaki and aged rats

We previously reported that treatment of streptozotocin-induced diabetic rats with zinc plus cyclo (his-pro) (CHP) decreased fed blood glucose levels and water intake. The present study was conducted to examine the dose-dependent, acute, and chronic treatment effects of CHP on oral glucose tolerance (OGT), fed blood glucose levels, water intake, and plasma insulin levels in young and aged Sprague-Dawley (S-D) rats, nondiabetic Wistar rats, and genetically diabetic Goto-Kakizaki (G-K) rats. Acute gastric gavage of 10 mg zinc plus 1.0 mg CHP/kg body weight significantly improved OGT in 4- and 13-month-old nondiabetic S-D rats and in 2-month-old diabetic G-K rats. Young S-D and G-K rats returned to pretreatment OGT values 1 week after acute gavage of zinc plus CHP (ZC), but improved OGT values persisted for at least 1 week after gavage in aged S-D rats. OGT values and fed blood glucose decreased to the greatest extent among other treatments when G-K rats were given free access to drinking water containing 1.0 to 1.5 mg CHP/L plus 10 mg zinc/L for 2 weeks. Although food and water intake showed a tendency to decrease, no statistically significant differences were observed in young G-K rats. Plasma insulin levels and blood glucose levels in both normal and diabetic G-K rats decreased with 2-week treatment with ZC. To test the direct effects of ZC on muscle tissue, we observed the effect of various doses of ZC on normal and G-K rat muscle slices. The optimal level of CHP alone for maximal muscle glucose uptake in muscle slices from normal rats was 10 microg/mL and 5.0 microg/mL in G-K rats, and ZC stimulated glucose uptake. However, no statistically significant difference was demonstrated between normal and G-K rat tissues in this study. These results indicate that oral intake of an optimal dose of ZC stimulates blood glucose metabolism, probably by stimulating muscle glucose utilization.     

Progression of early phase diabetic nephropathy in streptozotocin-induced diabetic rats: evaluation of various kidney-related parameters

Diabetic nephropathy (DN) is one of the serious secondary complications of diabetes, which results in end-stage renal failure. Reports on the progressive nature of early phase DN especially with respect to kidney parameters such as kidney weight, type IV collagen excretion, total kidney and urinary glycosaminoglycans (GAGs) are few. This work was undertaken to determine systematically the progression of early phase DN in relation to various kidney-related parameters for a period of four months. Experimentally-induced diabetic rats were grouped based on fasting blood glucose levels. Various basic and kidney-related parameters such as kidney weight, microalbuminuria, urinary excretion of GAGs and type IV collagen, total kidney GAGs, histopathology, glomerular area and glomerular volume were examined in control and diabetic rats. There was a progressive increase in fasting blood sugar, urine sugar, kidney weight, microalbuminuria, urine glycosaminoglycans, urine type IV collagen, glomerular area and glomerular volume but there was a progressive decrease in kidney glycosaminoglycans. Glomerular sclerotic condition was aggravated with the increase in duration of diabetes from 1 to 4 months. Onset of DN in rats begins subtly after one month of diabetes but gets vitiated and more pronounced at the end of four months.     

Role for thromboxane A2 from glomerular thrombi in nephropathy with type 2 diabetic rats

We used rats (the Otsuka Long-Evans Tokushima Fatty strain) as a model of type 2 diabetes to find whether thromboxane (TX) A2 is involved in diabetic nephropathy, and if so, to identify where it is synthesized. We measured urinary excretion of TXB2 and 2,3-dinor-TXB2 in rats up to 60 weeks of age as markers of renal and platelet synthesis of TXA2, respectively. Some diabetic rats were given daily oral doses of OKY-046 (100 mg/kg), a TXA2 synthase inhibitor, starting when they were 10 weeks of age. Healthy Long-Evans Tokushima Otsuka rats served as the controls. Urinary excretion of protein was greater in diabetic rats at 26 weeks than in controls, and the difference increased with age. Urinary excretion of TXB2 by diabetic rats was about 150% that of controls at 14 weeks, and remained at that level. In diabetic rats, urinary excretion of 2,3-dinor-TXB2 increased with age in parallel to increases in proteinuria, but in controls, excretion of these metabolites did not change with age. In diabetic rats, OKY-046 prevented the increase in urinary excretion of both metabolites, and decreased the proteinuria. Histologic examination at 60 weeks showed intraglomerular thrombi in diabetic rats but not in controls. OKY-046 reduced intraglomerular thrombi formation and the score for glomerulosclerosis. When platelet aggregation began, more TXA2 than before was released from the thrombi that formed, and the TXA2 contributed to the progress of nephropathy in this rat model of type 2 diabetes.     

普罗布考对糖尿病大鼠肾组织氧化应激的影响

目的研究普罗布考（Probucol）对糖尿病大鼠肾组织氧化应激的影响。方法采用腹腔注射链脲佐菌素（STZ）建立糖尿病大鼠模型。30只Wistar大鼠分为正常对照组（NC）、糖尿病组（DM）、糖尿病普罗布考治疗组（DP）。8周末称取体重、肾重、计算肾肥大指数（肾重/体重）,检测尿白蛋白排泄率（UAER）;测定各组生化指标包括血糖（BG）、胆固醇（TC）、三酰甘油（TG）、血清肌酐（SCr）、血尿素氮（BUN）;检测肾组织中丙二醛（MDA）的含量及超氧化物歧化酶（SOD）、过氧化氢酶（CAT）与谷胱甘肽过氧化物酶（GSH-Px）活性;肾组织切片行PAS染色分析肾小球面积及肾小球体积。结果 DM组大鼠肾重、肾重/体重、UAER、TC、TG、SCr、BUN、肾小球面积、肾小球体积较NC组均明显增加,DP组上述改变较DM组均明显减轻（P〈0.05）。DP组肾组织中MDA含量明显低于DM组,SOD、CAT、GSH-Px活性明显高于DM组（P〈0.05）。结论普罗布考可能部分通过减轻肾组织氧化应激反应实现对糖尿病大鼠肾脏的保护作用。     

Glomerular hyperfiltration in hypertensive fawn-hooded rats

The glomerular filtration rate (GFR), effective renal plasma flow (ERPF), systolic blood pressure (SBP) and urinary protein excretion (UpV) were determined in 12-week-old male rats of the spontaneously hypertensive Fawn-Hooded (FH) strain. These data were compared with those of either age-matched or weight-matched male, normotensive Wistar Albino Glaxo (WAG) rats. The GFR was significantly higher in FH rats than in both WAG control groups. In contrast, the ERPF did not differ between the FH and WAG rats. Thus, a higher filtration fraction was present in the FH rats. As no differences were found in the total number of glomeruli per kidney comparing FH and WAG rats, the high GFR was not due to an increase in the number of glomeruli. The SBP and the UpV were significantly higher in FH rats than in WAG rats. To our opinion, the arterial hypertension associated with glomerular hyperfiltration proteinuria suggests the presence of glomerular hypertension in FH rats.     

Altering expression of alpha3beta1 integrin on podocytes of human and rats with diabetes

The adhesion molecule integrin alpha3beta1 is the major receptor of podocyte to the glomerular capillary basement membrane (GBM). Since progressive alteration of the glomerular extracellular matrix (ECM) compartment leading to GBM thickening is common in diabetic nephropathy, we investigated the cellular distribution of alpha3beta1 integrin in podocytes of patients with diabetic nephropathy and streptozotocin-induced diabetic rats, and we evaluated the effects of high glucose on the cultured rat podocytes. Both human and rat kidneys were stained using the immunoelectron microscopy and immunoperoxidase technique with mouse monoclonal antibodies to human integrin alpha3 subunit. The results showed that both the number of immunogold particles and the staining of integrin alpha3 subunit on podocytes were weaker in patients with diabetic nephropathy than those of control kidneys. The staining of alpha3 on podocytes in the poorly-controlled diabetic rats was also weaker after one and three months of hyperglycemia. However, the staining was identical to controls in rats with only one week of hyperglycemia. High glucose (25 mM) but not streptozotocin in vitro suppressed the alpha3 expression of cultured rat podocytes. Our results demonstrated that the expression of integrin alpha3beta1 on podocytes was suppressed in both human and rats with diabetes, possibly due to the effects of hyperglycemia, and the suppression became more severe with the duration of diabetes.     

Activation of vasopressinergic and oxytocinergic neurons during aging in the Wistar rat

The activity of the hypothalamo-neurohypophyseal system (HNS) was determined in male Wistar rats from 3 to 32 months of age. Plasma levels of vasopressin (AVP) and oxytocin (OXT) were measured by means of a radioimmunoassay. In addition, the distribution of the Golgi apparatus marker enzyme thiamine-pyrophosphatase (TPP-ase) was measured as a parameter for neurosecretory activity in the hypothalamic supraoptic and paraventricular nuclei (SON and PVN). Plasma levels of radioimmunoassayable AVP were increased in the 32-month-old animals. Plasma levels of radioimmunoassayable OXT in 32-month-old animals did not differe from the levels found in the youngest group, but were higher than in 11-month-old animals. Neurosecretory activity in the SON was similar in 3- and 32-month-old animals, whereas in the PVN neurosecretory activity was increased in the 32-month-old animals. Urine excretion decreased between 6 and 11 months of age and remained on the same level until 32 months of age. In other words, instead of a loss of HNS function as has been suggested in the literature, an increased neurosecretory activity was observed in aged rats.     

阿霉素肾病大鼠尿液糖胺聚糖与尿液蛋白含量的相关性

目的探讨阿霉素肾病大鼠疾病进展过程中尿液糖胺聚糖含量的变化及其与尿蛋白的关系。方法采用一次性尾静脉注射阿霉素6mg/kg制作肾病综合征大鼠模型,第1、2、3、4、6周分别收集大鼠24h尿液测定尿糖胺聚糖和尿蛋白含量。43d后结束实验取血及肾脏,检测血生化,观察肾组织病理改变。结果第2、3、4、6周与正常对照组比较,阿霉素肾病大鼠24h尿蛋白排泄量呈进行性明显上升趋势;造模43d后模型组血清白蛋白含量显著下降,总胆固醇和甘油三酯含量显著升高,肾组织病理所见,模型组肾小球系膜区见中度至重度的系膜细胞增殖及基质增生。从第3周开始阿霉素肾病大鼠尿糖胺聚糖浓度显著高于正常组,且与24h尿蛋白排泄量呈正相关关系。第6周尿糖胺聚糖浓度与血清白蛋白浓度负相关,与甘油三酯浓度正相关。结论阿霉素肾病综合征大鼠尿液中糖胺聚糖浓度升高,并与24h尿蛋白排泄、血清白蛋白、甘油三酯浓度显著相关。     

The renal expression of heat shock protein 47 and collagens in acute and chronic experimental diabetes in rats

Glomerulosclerosis and tubulointerstitial fibrosis are the main structural changes found in the later stages of diabetic nephropathy, which is clinically characterized by proteinuria, and progressive renal insufficiency. Heat shock protein (HSP) 47, a collagen-binding stress protein, has a specific role in the intracellular processing of procollagen molecules during collagen synthesis. It is implicated in the pathogenesis of various fibrotic diseases. However, the expression and significance of HSP47 in acute and chronic phases of diabetic nephropathy is not yet known. In this study, we studied the expression of HSP47 in the kidneys obtained from streptozotocin-induced diabetic rats, in both short- and long-term diabetes. To determine the renal expression of HSP47, and collagens (type III and IV) in acute (days 1, 3 and 14) and chronic (weeks 4, 12 and 24) diabetes, we have performed a time-course study using streptozotocin-induced diabetic rats. The expression pattern of alpha-smooth muscle actin (to identify mesangial cell damage), vimentin (to identify tubular epithelial cell damage), and desmin (to identify glomerular epithelial cell damage) was also determined in kidneys of these diabetic rats. Antibodies specific for HSP47, type III and type IV collagens, alpha-smooth muscle actin, vimentin, and desmin were used to assess the relative expression of their proteins in paraffin-embedded kidney sections by immunohistochemistry. Compared to control rat kidneys, no significant changes in the expression of HSP47 was found in the kidneys of acute diabetic rats. However a significant increase in the expression of HSP47 was noted in the kidneys of chronic diabetic rats; increased expression of HSP47 correlated with an increased renal deposition of types III and IV collagens. Similarly, compared to kidneys of control and acute diabetic rats, an increased expression of alpha-smooth muscle actin (in mesangial cells), vimentin (in tubular epithelial cells), and desmin (in glomerular epithelial cells) was detected in the kidneys of chronic diabetic rats; by dual immunostaining, these phenotypically-altered renal cells in kidneys of chronic diabetic rats were found to be HSP47-producing cells. Importantly, HSP47 up-regulation coincided with the initiation and progression of renal fibrosis, as determined by the expression and deposition of collagens. Our results strongly support a pathological role for HSP47 in the later stages (sclerotic phase) of streptozotocin-induced diabetic nephropathy, which is associated with glomerulosclerosis and tubulointerstitial fibrosis.