Aminoguanidine impedes human pancreatic tumor growth and metastasis development in nude mice

AIM:To study the action of aminoguanidine on pancreatic cancer xenografts in relation to cell proliferation,apoptosis,redox status and vascularization.METHODS:Xenografts of PANC-1 cells were developed in nude mice. The animals were separated into two groups:control and aminoguanidine treated. Tumor growth,survival and appearance of metastases were determined in vivo in both groups. Tumors were excised and ex vivo histochemical studies were performed. Cell growth was assessed by Ki-67 expression. Apoptosis was studied by intratumoral expression of B cell lymphoma-2 protein (Bcl-2) family proteins and Terminal deoxynucleotidyl transferase biotin-dUTP Nick End Labeling (Tunel). Redox status was evaluated by the expression of endothelial nitric oxide synthase (eNOS),catalase,copper-zinc superoxide dismutase (CuZnSOD),manganese superoxide dismutase (MnSOD) and glutathione peroxidase (GPx). Finally,vascularization was determined by Massons trichromic staining,and by VEGF and CD34 expression.RESULTS:Tumor volumes after 32 d of treatment by aminoguanidine (AG) were significantly lower than in control mice (P < 0.01). Median survival of AG mice was significantly greater than control animals (P < 0.01). The appearance of both homolateral and contralateral palpable metastases was significantly delayed in AG group. Apoptotic cells,intratumoral vascularization (trichromic stain) and the expression of Ki-67,Bax,eNOS,CD34,VEGF,catalase,CuZnSOD and MnSOD were diminished in AG treated mice (P < 0.01),while the expression of Bcl-2 and GPx did not change.CONCLUSION:The antitumoral action of aminoguanidine is associated with decreased cell proliferation,reduced angiogenesis,and reduced expression of antioxidant enzymes.

Effect of aminoguanidine on caspase-3 expression in rat retina after ischemia-reperfusion injury

AIM: To investigate the effect of aminoguanidine (AG) on the Expression of caspase-3 in rat retina after ischemia-reperfusion injury. METHODS: The rats were anesthetized with 30mg/kg sodium pentobarbital introperitoneal (ip) injections. After topical application of 10g/L dicaine, the anterior chamber was punctured with a 5-gauge needle connected to a bottle containing normal saline. Intraocular pressure was raised to 100 mmHg by elevating the saline container. The infusion needle was removed from the anterior chamber 60 minutes later. Reperfusion of the retinal vasculature was confirmed by fundus examination. AG 100mg/kg was ip injected in drug group. The rats were then euthanatized at 6, 24, and 72 hours after reperfusion, and their eyes were enucleated for immunohistochemistry. RESULTS: No specific staining was detected by using the caspase-3 antibody in the retina of control group. In ischemia group, the protein of caspase-3 was over-expressed at 6 hours and relieved at 24 hours and 72 hours, while with drug treatment, the expression of protein of caspase-3 was decreased at each time point. CONCLUSION: AG provides retinal protection against ischemia-reperfusion injury in rat retina, probably through an inducible NOS-dependent mechanism.

Effects of aminoguanidine on retinal apoptosis in mice with oxygen-induced retinopathy

AIM:To explore the protective effects of amino-guanidine(AG) on retinal apoptosis in mice with oxygeninduced retinopathy(OIR).·METHODS:A total of 80 C57BL/6J mice,aged 7 days,were randomly divided into four groups:normal,high oxygen,high oxygen saline and high oxygen treated with AG.In the normal group,mice were housed in normoxic conditions from postnatal day P7 to P17.Mice in the other 3 groups were placed under hyperoxic conditions(75 ±2% O2) in an oxygen-regulated chamber for 5 days and subsequently placed in normoxic conditions for 5days.Mice in the AG group were treated once daily,from P12 to P17,with AG hemisulfate(100mg/kg body weight,intraperitoneally) dissolved in physiological saline.An equivalent amount of 0.9% physiological saline was administered,as above,to mice in the high oxygen saline group.Ten mice were randomly selected from each group on P14 and on P17,euthanized and the retinas examined.Apoptotic cells in the retina were detected using the terminal-deoxynucleoitidyl transferase mediated nick end labeling(TUNEL) method.The expression of nitric oxide synthase(iNOS) in the retina was detected by immunohistochemistry and changes in rod cells were observed using electron microscopy.·RESULTS:TUNEL-positive cells and iNOS immunoreactive neurons were present in the inner nuclear and ganglion cell retinal layers of mice in the high oxygen group.The number of TUNEL-positive cells was significantly greater in the high oxygen group compared with the normal group(t =-20.81,P14d【0.05;t =-15.05,P17d【0.05).However,the number of TUNEL-positive cells in the AG treatment group was significantly lower(t =-13.21,P14d【0.05;t =-6.61,P17d【0.05) compared with thehigh oxygen group.The expression of iNOS was significantly higher in the high oxygen group compared with the normal group(t =-21.95,P14d【0.05;t =-17.30,P17d【0.05).However,the expression of iNOS in the AG treatment group was significantly lower(t =-12.17,P14d【0.05;t =-10.30,P17d【0.05) compared with the high oxygen group.The outer segments of the rods were disorganized and short in the high oxygen group.Rod morphology appeared to be slightly improved in the AG group.·CONCLUSION:AG may protect retinal neurons in OIR by inhibiting apoptosis.The mechanism may be related to iNOS.

Molecular Structure of Aminoguanidine Sulfate Monohydrate

The single crystal of aminoguanidine sulfate monohydrate [（AG）2SO4· H2O] is obtained and its structure is determined by X-ray diffraction analysis. The compound crystallizes in orthorhombic system with space group Pnma and the empirical formula C2H16N8O5S. The unit cell parameters are as follows： a = 0.675 9（2）nm, b = 1.413 1（5）nm, c = 1. 165 0（4）nm, V = 1.112 8（6）nm^3, Z = 4, Dc = 1.578 g/cm^3, F（000） =560, s = 1.069, μ（MoKa） =0.318 mm^-1. The final R and wR are 0.031 2 and 0.083 3, respectively. The title compound is an ionic compound and its structure unit consists of two aminoguanidium cations, one sulfate anion and one crystal water molecule, which are interconnected by electrostatic forces and hydrogen bonds into net structure, making the title compound very stable. Under a linear heating rate, the thermal decomposition processes of （AG）2SO4·H2O have one endothermal dehydration stage, one melting process and one exothermic decomposition stage at 50 - 400 ℃, and can evolve abundant gas products.

Glycation Induced Physicochemical Changes in Low-Density Lipoprotein and Its Role in Promoting Cholesterol Accumulation in Macrophages along with Antiglycation Effect of Aminoguanidine

The present study aimed at investigating physicochemical changes in modified LDL by sugars specifically fructose due to recent reports on its involvement in cardiovascular diseases and also glucose and their role in subsequent in vitro accumulation of cholesterol in macrophages. Antiglycation action of aminoguanidine was also investigated. LDL isolated from human blood was incubated with fructose or glucose and aminoguanidine where indicated. The physicochemical changes in modified LDL were detected by electrophoretic, spectroscopic and chemical analysis. Accumulation of cholesterol and its inhibiton in human monocyte-derived macrophages incubated with modified LDL was determined by HPLC. Results showed increased relative electrophoretic mobility, hyperchromicity at 280 nm, development of AGE fluorescence, decrease in free amino groups and increased carbonyl content in glycated LDL as compared to native LDL. Also total cholesterol accumulated in macrophages was more for glycated LDL as compared to native LDL. The magnitude of changes was more prominent in case of fructose as compared to glucose. Aminoguanidine showed remarkable restriction of glycation-induced alterations in LDL and also in accumulation of cholesterol in macrophages. The study thus proclaims that LDL-AGEs formed by fructose may contribute to accelerated initiation of diabetes induced atherosclerosis via foam cells generation and aminoguanidine may have therapeutic potential against it.

Electrochemical Evaluation of Aminoguanidine Hydrazone Derivative with Potential Anticancer Activity:Studies of Glassy Carbon/CNT and Gold Electrodes Both Modified with PAMAM

Aminoguanidine hydrazones (AGHs) are a class of compounds that have interesting pharmacological activities. They are derived from the same chemical group as aminoguanidine, so it has mixed properties (receptor and donor) in the formation of hydrogen bonds. Its anticancer agent properties were recently highlighted, but the molecules of this class have solubility in aqueous solutions that can be considered low. The identification of this class, by a simple, sensitive and low-cost technique, such as electrochemistry, which also allows the evaluation of its solubilization process through agents such as PAMAM dendrimer is the main objective of the work described here. The electrochemical response of the LQM10 (AGH derivative) was evaluated, as well as its behavior in different electrochemical sensors. Electrochemical experiments were performed in buffered (phosphate at pH 7.02 and acetate at 4.5). LQM10 has a reversible oxidation peak with a potential of +0.22 V. It was efficiently detected in different electrodes tested (glass carbon/CNT, glass carbon/CNT/PAMAM), which proves the viability of the electrodes for various analyses and has the determination of the apparent constant association, indicating its interaction with the analysis that is higher in the presence of the PAMAM encapsulating agent. This was corroborated by the results for the modified gold electrode with MUA and PAMAM. The sum of the results shows the possibility of electrochemically evaluating the Aminoguanidine hydrazone derivative, the viability of electrodes employed and the greater solubilization of LQM10 in the presence of the PAMAM dendrimer.

Aminoguanidine delays the replicative senescence of human diploid fibroblasts

Background The accumulation of free radicals and advanced glycation end products （AGEs） in cell plays a very important role in replicative senescence. Aminoguanidine （AG） has potential antioxidant effects and decreases AGE levels. This study aimed to investigate its effect on replicative senescence in vitro. Methods The effects of aminoguanidine on morphology, replicative lifespan, cell growth and proliferation, AGEs, DNA damage, DNA repair ability and telomere length were observed in human fetal lung diploid fibroblasts （2BS）. Results Aminoguanidine maintained the non-senescent phenotype of 2BS cells even at late population doubling （PD） and increased cumulative population doublings by at least 17-21 PDs. Aminoguanidine also improved the potentials of growth and proliferation of 2BS cells as detected by the MTT assay. The AGE levels of late PD cells grown from early PD in DMEM containing aminiguanidine decreased significantly compared with those of late PD control cells and were similar to those of young control cells. In addition, the cells pretreated with aminoguanidine had a significant reduction in DNA strand breaks when they were exposed to 200 μmol/L H2O2 for 5 minutes which indicated that the compound had a strong potential to protect genomic DNA against oxidative stress. And most of the cells exposed to 100 μmol/L H2O2 had much shorter comet tails and smaller tail areas after incubation with aminoguanidine-supplemented DMEM, which indicated that the compound strongly improved the DNA repair abilities of 2BS cells. Moreover, PD55 cells grown from PD28 in 2 mmol/L or 4 mmol/L aminoguanidine retain telomere lengths of 7.94 kb or 8.12 kb, which was 0.83 kb or 1.11 kb longer than that of the control cells. Conclusion Aminoguanidine delays replicative senescence of 2BS cells and the senescence-delaying effect of aminoguanidine appear to be due to its many biological properties including its potential for proliferation improvement, its inhibitory effect of AGE formation, antioxidant effect, improvement of DNA repair ability and the slowdown of telomere shortening.

一氧化氮在梗阻性黄疸大鼠肝、肾、肠组织中含量变化及意义

目的 了解一氧化氮（NO）在梗阻性黄疸大鼠肝、肾、肠组织中含量变化及意义。方法 大鼠胆总管结扎后,分别于第一周内和第三周内应用Aminoguanidine（AG）抑制NO合成,同时应用生理盐水（NS）作对照,检测不同时段抑制NO合成后大鼠肝、肾、肠组织中NO和丙二醛（MDA）含量、肌酐清除率（Ccr）血清总胆红素（T-BIL）和丙氨酸氨基转移酶（ALT）含量及肠系膜淋巴结细菌移位（BT）率的变化。结果 胆总管结扎后,大鼠肝、肾、肠组织中NO含量明显升高,在胆总管结扎第一周抑制NO合成后,肝、肾、肠组织中NO含量明显下降,MDA含量明显升高,血ALT明显升高、Ccr明显下降、肠系膜淋巴结BT率明显升高;而在胆总管结扎第三周抑制NO合成后,肝、肾、肠组织中NO和MDA含量明显下降,血ALT明显下降、Ccr明显升高。肠系膜淋巴结BT率明显下降。结论NO在胆道梗阻引起的肝、肾、肠粘膜屏障功能障碍的发生机制中具有重要作用,既有保护作用,又有损害作用。梗阻早期表现为对组织的保护作用,后期表现为对组织的损害作用。

Structural and Functional Changes of Immune System in Aging Mouse Induced by D-Galactose

Objective To investigate the role of D-galactose, especially in the structural and functional changes of the immune system in aging. Methods Serum levels of advanced glycation end-products （AGE） were determined by ELISA method. Ultra-structures of thymus and spleen were detected by transmission electron microscopy. MTT method was used to determine the lymphocyte proliferation. IL-2 activity was determined by bioassay. Northern blot was used to detect the IL-2 mRNA levels. Results Serum AGE levels of D-galactose- （P〈0.01） and AGE-treated （P〈0.05） mice （n=8） were increased significantly. The ultra-structures of thymus and spleen in D-galactose- and AGE-treated mice showed regressive changes similar to those in the aged control group. The lymphocyte mitogenesis and IL-2 activity of spleen were also decreased significantly （P〈0.01, n=8）. The change of IL-2 activity shown by Northern blot resulted from the change of mRNA expression. The AGE plus aminoguanidine group, however, showed no significant change in these parameters in comparison with the young control group （P〈0.01 or P〈0.05, n=8）. Conclusion D-galactose and AGE lead to a mimic regression change of aging in the immune system in vivo.

Protective effect of inducible nitric oxide synthase inhibitor on pancreas transplantation in rats

AIM: To investigate the effect of inducible nitric oxide synthase inhibitor, aminoguanidine, on pancreas transplantation in rats. METHODS: A model of pancreas transplantation was established in rats. Streptozotocin-induced diabetic male Wistar rats were randomly assigned to sham-operation control group (n= 6), transplant control group (n= 6), and aminoguanidine (AG) treatment group (n=18). In the AG group, aminoguanidine was added to intravascular infusion as the onset of reperfusion at the dose of 60 mg/kg, 80 mg/kg, 100 mg/kg body weight, respectively. Serum nitric oxide (NO) level, blood sugar and amylase activity were detected. Nitric oxide synthase (NOS) test kit was used to detect the pancreas cNOS and inducible NOS (iNOS) activity. Pancreas sections stained with HE and immunohistochemistry were evaluated under a light microscope. RESULTS: As compared with the transplant control group, the serum NO level and amylase activity decreased obviously and the evidence for pancreas injury was much less in the AG group. The AG (80 mg/kg body weight) group showed the most signifi cant difference in NO and amylase (NO: 66.0 ± 16.6 vs 192.3 ± 60.0, P < 0.01 and amylase: 1426 ± 177 vs 4477 ± 630, P < 0.01). The expression and activity of tissue iNOS, and blood sugar in the AG (80 mg/kg body weight) group were much lower than those in the transplant control group (iNOS: 2.01 ± 0.23 vs 26.59 ± 5.78, P < 0.01 and blood sugar: 14.2 ± 0.9 vs 16.8 ± 1.1, P < 0.01). CONCLUSION: Selective iNOS inhibitor, aminoguanidine as a free radical, has a protective effect on pancreas transplantation in rats by inhibiting NO and reducing its toxicity.

Influence of tonifying kidney recipe on advanced glycation endproducts and lipid peroxidation in ovariectomized rats

BACKGROUND： Previous studies have demonstrated that reduced estrogen levels may accelerate the formation of advanced glycation endproducts （AGE） in brain tissue, raise the concentration of lipid peroxidation products in vivo, and speed up deterioration of learning and memory. A tonifying kidney recipe is hypothesized to improve the ability of learning and memory in ovariectomized rats by downregulating AGE and lipid peroxidation products. OBJECTIVE： To simulate a postmenopausal state, bilateral ovariectomy （OVX） was performed in rats, and the effects of tonifying kidney recipe （TKR） on AGE and lipid peroxidation in the rat cerebral cortex, hippocampus, and blood serum levels was measured. In addition, the effects on learning and memory were evaluated, and the effect of AGE -specific inhibitor aminoguanidine （AG） was compared with TKR. DESIGN, TIME AND SETTING： A randomized, in vivo, control experiment was performed at the scientific research center （Provincial Key Laboratory） in the Fourth Hospital of Hebei Medical University （Shijiazhuang, Hebei Province, China） from May 2005 to January 2007. MATERIALS： Forty healthy, adult, female, Sprague Dawley rats were used for this study. TKR was composed of prepared rehmannia rhizome, epimedium herb, desert-living cistanche, and Szechwan lovage rhizome, which were provided by Shijiazhuang Medical Materials Company （China）. A TKR extraction was prepared for further use. AG was provided by Sigma （USA）. Forty rats were randomly divided into four groups： sham, OVX, AG, and TKR, with 10 rats in each group. METHODS： The rat ovaries were resected in the OVX, AG, and TKR groups, whereas the same volume of fat was resected in the sham group. At four weeks after OVX, the AG group received 1% AG water solution by lavage; the TKR group was administrated by lavage once per day at a dose of 6.3 g （crude drug）/kg; OVX and sham groups received equal volumes of tap water. MAIN OUTCOME MEASURES： Learning and memory behavior of rats was tested in a Y-electric maze 16 weeks after the OVX procedure. The contents of advanced glycation endproducts in the rat cerebral cortex, hippocampus, serum, and urine were detected by competitive ELISA and spectrofluorophotometer. The contents of lipid peroxidation in rat serum, cerebral cortex, and hippocampus were assayed using a biochemical method. RESULTS： Compared with the sham group, serum content of advanced glycation endproducts in the OVX group was significantly increased, and lipid peroxidation content increased in cerebral cortex, hippocampus, and serum （t = 3.04-4.22, P 〈 0.05 0.01）. Both AG and TKR decreased the amount of AGE in cerebral cortex and serum （t = 2.53, 3.64, P 〈 0.05, 0.01）, increased AGE urine content （t = 3.25 4.87, P 〈 0.01）, and decreased lipid peroxidation content in cerebral cortex, hippocampus, and serum （t = 2.80 3.70, P 〈 0.05 0.01）. In comparison to the OVX and sham groups, the correct escape rate in the Y-electric maze was significantly increased （t = 3.46, 3.28, P 〈 0.01）, and escape latency was significantly decreased （t=3.12, 2.48 P 〈 0.05） in the AG and TKR groups, which indicated that both AG and TKR improved learning and memory The OVX group had a significantly lower correct escape compared with the sham group （t = 4.21, P 〈 0.01 ）.CONCLUSION： The tonifying kidney recipe decreased deposition of advanced glycation endproducts and lipid peroxidation in ovariectomized rats, and concomitantly improved learning and memory. The effect of TKR was equal to that of AG.

SIRT2 regulates microtubule stabalization in diabetic cardiomyopath＇.

Aim Stable microtubules （MTs） is involved the mechanism of diabetic cardiomyopathy （DCM）, which is induced by acetylation of α-tubulin. The present study investigated whether SIRT2, a deacetylase, regulates MT stability through α-tubulin deacetylation in DCM and whether the receptor of advanced glycation end products （AGEs） signaling pathway is involved in this effect. Methods Type 1 diabetic mellitus （T1DM） rats model was established by a single intraperitoneal injection of streptozotocin （STZ, 65 mg · kg^-1） , and neonatal rat cardio- myocytes were also cultured. Heart function was detected by Doppler. MT stability was elevated by β-tubulin ex- pression density. The protein expression of SIRT2, acetylated α-tubulin and AGEs receptor were detected by immu- nohistochemistry or Western blots. The interaction of SIRT2 and acetylated α-tubulin was detected by Co-immuno- precipitation. Results In an animal model of T1DM, Western blot and immunohistochemistry revealed downregu- lation of SIRT2 but upregulation of the acetylated α-tubulin protein. These effects were reduced by treatment of aminoguanidine, an inhibitor of AGEs production. HDAC6 expression did not regulated in heart. In primary cul- tures of neonatal rat cardiomyocytes, the AGEs treatment impaired the SIRT2/acetylated α-tubulin signaling path- way, and SIRT2-overexpression reversed the function of AGEs on cardiomyocytes. In addition, gene silencing of AGEs receptor alleviated the impairment effect of AGEs on cardiomyocytes. Conclusion In conclusion, these data demonstrate that AGEs/AGEs receptor promote MT stabilization via the suppression of the SIRT2/acetylated α-tu- bulin signaling pathway in DCM development.

Role of gastric oxidative stress and nitric oxide in formation of hemorrhagic erosion in rats with ischemic brain

AIM： To investigate the role of gastric oxidative stress and nitric oxide （NO） in the formation of gastric hemorrhagic erosion and their protection by drugs in rats with ischemic brain. METHODS： Male Wistar rats were deprived of food for 24 h. Under chloral hydrate （300 mg/kg） anesthesia, bilateral carotid artery ligation was performed. The pylorus and carotid esophagus of the rats were also ligated. The stomachs were then irrigated for 3 h with either normal saline or simulated gastric juice containing 100 mmol/L HCI plus 17.4 mmol/L pepsin and 54 mmol/L NaCI. Rats were killed and stomachs were dissected. Gastric mucosa and gastric contents were harvested. The rat brain was dissected for the examination of ischemia by triphenyltetrazolium chloride staining method. Changes in gastric ulcerogenic parameters, such as decreased mucosal glutathione level as well as enhanced gastric acid back-diffusion, mucosal lipid peroxide generation, histamine concentration, luminal hemoglobin content and mucosal erosion in gastric samples, were measured. RESULTS： Bilateral carotid artery ligation produced severe brain ischemia （BI） in rats. An exacerbation of various ulcerogenic parameters and mucosal hemorrhagic erosions were observed in these rats. The exacerbated ulcerogenic parameters were significantly （P〈 0.05） attenuated by antioxidants, such as exogenous glutathione and allopurinol. These gastric parameters were also improved by intraperitoneal aminoguanidine （100 mg/kg） but were aggravated by N^G-nitro-L-argininemethyl ester （L-NAME： 25 mg/kg）. Intraperitoneal L-arginine （0-500 mg/kg） dose-dependently attenuated BI-induced aggravation of ulcerogenic parameters and hemorrhagic erosions that were reversed by L-NAME. CONCLUSION： BI could produce hemorrhagic erosions through gastric oxidative stress and activation of arginine-nitric oxide pathway.

Synthesis, Thermal Behaviour, XRD, and Luminescent Properties of Lighter Lanthanidethiodipropionate Hydrates Containing Aminogunidine as Neutral Ligand

Aminoguanidine lanthanide thiodipropionate hydrates of composition [Ln(Agun)2(tdp)3&#183nH2O], Agun = Aminoguanidine, tdp = thiodipropionic acid, where Ln = La, Pr, Nd and Sm if n = 2, have been prepared and characterized by physic-chemical techniques.

Nitridergic Modulation of the Antinociceptive Activity of Rosuvastatin in Mice

Statins, 3-hydroxy-3 methylglutaryl coenzyme A (HMG-CoA) reductase enzyme inhibitors, are lipid-lowering drugs, often used in the treatment of cardiovascular diseases (hyperlipidemia, atherosclerosis). It has been shown that statins have antiinflammatory effects independent of their lipid-lowering effects and these anti-inflammatory effects inhibit the inflammation and pain process. This study evaluated the antinociceptive and anti-inflammatory effects of rosuvastatin using the acetic acid writhing, the formalin hind paw, the orofacial formalin and the hot plate tests. The following experimental group were used: control, acute (1 day) and chronic (3 days) after oral gavage with rosuvastatin (3, 10, 30, 100 and 300 mg/kg). Rosuvastatin produced a dose-dependent antinociception, with different potency, in all the tests. Additionally, nitric oxide synthase inhibitors (Abbreviationsand aminoguanidine) were used to assess the nitric oxide participation on this induced rosuvastatin antinociception. The data demonstrated the antinociceptive and anti-inflammatory activity of rosuvastatin in algesiometer models of tonic or phasic pain. These activities seem to be induced by modulation of iNOS expression, a result that may be relevant in the pharmacological treatment of human pain where rosuvastatin and nitric oxide synthase inhibitors must be used.

Effect of advanced glycosylation end products on activity of protein kinase C in human peripheral blood mononuclear cells

To investigate the effect of advanced glycosylation end products (AGEs) on the activity of protein kinase C (PKC) in human peripheral blood mononuclear cells (PBMC) and to observe whether aminoguanidine (AG) can influence the effect of AGEs Methods After PBMC were isolated from human peripheral blood and incubated with different concentrations of AGEs BSA for various periods, total PKC activity in PBMC was determined by measuring the incorporation of 32 P from [γ 32 P] ATP into a special substrate using Promega PKC assay kit Results AGEs BSA increased the total PKC activity in PBMC from 83 43±6 57?pmol/min/mg protein to 116 8±13 82?pmol/min/mg protein with a peak at 15?min AGEs BSA also increased the total PKC activity in a concentration dependent manner from 83 1±6 4?pmol/min/mg protein (control) to 119 1±13 3?pmol/min/mg protein (control vs AGEs BSA 400?mg/L, P <0 01) Furthermore, AGEs BSA induced an elevation of PKC activity in a glycosylating time related manner, from 80 9±8 2 (control) to 118 3±11 5?pmol/min/mg protein (glycosylation for 12 wk, P <0 01) The total PKC activity stimulated by AGEs BSA pretreated with AG (100, 200?mg/L) was markedly lower than that of AGEs BSA group not pretreated with AG ( P <0 05, P <0 01) Conclusions AGEs BSA increased the total PKC activity in PBMC in a concentration and incubation time dependent manner The ability of AGEs BSA to stimulate PKC activity was markedly decreased by pretreatment of AGEs BSA with AG

Advanced glycosylation end products, protein kinase C and renal alterations in diabetic rats

To study the relationship between advanced glycosylation end products (AGE) and protein kinase C (PKC), and their effects on renal alteration in diabetic rats Methods Insulin or aminoguanidine was administered to diabetic rats Blood glucose, hemoglobin A 1C (HbA 1C ), glomerular tissue extracts AGE (GTE AGE), PKC, glomerular basement membrane thickness (GBMT) and urine protein/creatinine (Pr/Cr) ratio in diabetic rats were measured and analysed Results Levels of blood glucose, HbA 1C and AGE, PKC activity, the Pr/Cr ratio and GBMT were all significantly increased ( P values all less than 0 01) in diabetic rats Insulin could decrease the formation of HbA 1C and AGE, and improve PKC activity Aminoguanidine had no influence on PKC activity ( P >0 05) although it decreased the formation of AGE Both drugs could delay the increase of urine Pr/Cr ratio and GBMT ( P <0 05 or P <0 01) Conclusions Chronic hyperglycemia may lead to an increase of PKC activity HbA 1C and AGE may not directly contribute to alterations of PKC activity, but the increase of PKC activity could promote the action of AGE on GBM thickening It is important to inhibit the formation of AGE and reduce the PKC activity so as to prevent or delay the development of diabetic nephropathy