Protective Effect of Melatonin on the Nephrotoxicity by Cisplatin / 대한신장학회잡지

BACKGROUND: Cisplatin (CP), an antitumor agent widely used in the treatment of cancers, has nephrotoxicity. This side effect is closely related to oxidative stress. In the present study, we attempted to reduce CP-induced nephrotoxicity in rats by administering melatonin, an antioxidant. METHODS: Male Sprague-Dawley rats were divided into different groups and were treated as follows: (1) saline control; (2) CP (16 mg/kg, i.p.); (3) CP plus melatonin (10 mg/kg, i.p.). The rats were sacrificed at the 6th day after CP treatment. To evaluate renal damage, BUN, serum creatinine, creatinine clearance and microscopic examination were done. Hydrogen peroxide which is one of the oxygen free radicals, and malondialdehyde which is known as a marker of the oxygen free radical mediated injury, and the activities of the antioxidant enzymes such as superoxied dismutase, catalase, and glutathione peroxidase were also measured. RESULTS: CP-treated rats showed the increase of BUN, serum creatinine, malondialdehyde, hydrogen peroxide and superoxide dismutase (SOD) in kidney. And CP-treated rats also showed the decrease of creatinine clearance and catalase levels. CP-treated rats showed severe tubular necrosis in proximal convoluted tubules under the light microscopic examination. The light microscopic finding and all of the parameters except SOD were restored in the rats injected with CP plus melatonin than those with CP alone. SOD level was higher in the rats injected with CP plus melatonin than that with CP alone. CONCIUSION: These results suggest that melatonin suppresses CP-induced nephrotoxicity by suppressing the production of reactive oxygen species via the activation of SOD and catalase.

Metabolism of Reactive Oxygen Species in Neutrophils from Patients with End-Stage Renal Disease / 대한신장학회잡지

BACKGROUND: The present study was aimed to know the cause of impaired bactericidal activity, especially the metabolism of oxygen free radicals in neutrophils from patients with end-stage renal disease (ESRD). METHODS: We measured the amount of superox ide anion, the activity of three antioxidant enzymes, myeloperoxidase, copper ion level, zinc ion level and the amount of malondialdehyde in neutrophils from patients with ESRD before and after hemodialysis. Reverse transcription-polymerase chain reaction (RT-PCR) for superoxide dismutase (SOD) was also done. RESULTS: The malondialdehyde level, the amount of superoxide anion, catalase, and myeloperoxidase levels in the neutrophils from the patients with ESRD were higher than those from healthy controls. SOD activity, hydrogen peroxide level and zinc level were lower in ESRD patients. On the RT-PCR, the relative index, which is defined the ratio of the band densities for SOD to glyceraldehyde 3-phosphate dehydrogenase, was decreased in neutrophils from patients with ESRD. Glutathione peroxidase activity in the neutrophils from ESRD patients did not show any significant change. CONCLUSION: These results indicate that there are some alterations in metabolism of oxygen free radicals including lower levels of hydrogen peroxide which exerting a direct germicidal ability, due to decreased gene expression and mineral levels. And these alterations might be one of the major mechanisms of impaired microbicidal activity in patients with ESRD.

Effects of Intravenous Administration of Taurocholate on Liver and Serum Thiosulfate Sulfurtransferase Activities in Cholestatic Rat

PURPOSE: To Study the possible mechanisms of change of thiosulfate sulfurtransferase (TST) activity in cholestatic rat liver and serum. METHODS: Rats were divided into seven groups: those receiving a sham operation (Sham group), with a bile duct obstruction (BDO) alone (BDO group), with a BDO plus taurocholic acid (TCA) injection (BDO plus TCA group), with a BDO plus tauroursodeoxycholic acid (TUDCA) injection (BDO plus TUDCA group), a choledocho-caval shunt (CCS) operation (CCS groups), a CCS operation plus TCA injection (CCS plus TCA group) and a CCS operation plus TUDCA injection (CCS plus TUDCA group). The TST activities in the serum and in the hepatic subcellular fractions isolated from above experimental rats were determined. The Km and Vmax values of this hepatic enzyme were measured. RESULTS: The liver cytosolic, mitochondrial and microsomal TSTs activities, as well as the TST Vmax values were found to be significantly decreased in the BDO plus TCA and BDO groups compared to the control group. The activity and Vmax value of the liver cytosolic TST were also found to be significantly decreased in the CCS plus TCA group. Conversely, there was no variation in the Km values of the hepatic enzymes in any of the above experimental groups. The serum TST activities in the CCS plus TCA and BDO plus TCA groups, were significantly increased compared with the control, CCS and BDO groups. However, the serum and hepatic enzyme activities were unchanged in both the CCS plus TUDCA and BDO plus TUDCA groups. CONCLUSION: The above results indicate that TCA represses the biosynthesis of TST in the liver. Also, the elevated TST activity in the serum is most likely due to an increase in the permeability of hepatocytes membrane upon TCA mediated liver cell necrosis.

Effects of Intravenous Administration of Taurocholate on Liver and Serum Thiosulfate Sulfurtransferase Activities in Cholestatic Rat

PURPOSE: To Study the possible mechanisms of change of thiosulfate sulfurtransferase (TST) activity in cholestatic rat liver and serum. METHODS: Rats were divided into seven groups: those receiving a sham operation (Sham group), with a bile duct obstruction (BDO) alone (BDO group), with a BDO plus taurocholic acid (TCA) injection (BDO plus TCA group), with a BDO plus tauroursodeoxycholic acid (TUDCA) injection (BDO plus TUDCA group), a choledocho-caval shunt (CCS) operation (CCS groups), a CCS operation plus TCA injection (CCS plus TCA group) and a CCS operation plus TUDCA injection (CCS plus TUDCA group). The TST activities in the serum and in the hepatic subcellular fractions isolated from above experimental rats were determined. The Km and Vmax values of this hepatic enzyme were measured. RESULTS: The liver cytosolic, mitochondrial and microsomal TSTs activities, as well as the TST Vmax values were found to be significantly decreased in the BDO plus TCA and BDO groups compared to the control group. The activity and Vmax value of the liver cytosolic TST were also found to be significantly decreased in the CCS plus TCA group. Conversely, there was no variation in the Km values of the hepatic enzymes in any of the above experimental groups. The serum TST activities in the CCS plus TCA and BDO plus TCA groups, were significantly increased compared with the control, CCS and BDO groups. However, the serum and hepatic enzyme activities were unchanged in both the CCS plus TUDCA and BDO plus TUDCA groups. CONCLUSION: The above results indicate that TCA represses the biosynthesis of TST in the liver. Also, the elevated TST activity in the serum is most likely due to an increase in the permeability of hepatocytes membrane upon TCA mediated liver cell necrosis.

Effects of Intravenous Administration of Taurocholate on Hepatic Thiol Methyltransferase Activity in Cholestatic Rat

PURPOSE: The possible mechanisms of increased thiol me thyltransferase (TMT) activity in cholestatic rat livers and serum were studied. METHODS: Rats were divided into seven groups: rats receiv ing a sham operation, rats with a bile duct obstruction (BDO) alone (BDO group), rats with BDO plus taurocholic acid (TCA) injection (BDO plus TCA group), rats with BDO plus tauroursodeoxycholic acid (TUDCA) injection (BDO plus TUDCA group), rats receiving a choledoco-caval shunt (CCS) operation (CCS groups), rats receiving a CCS operation plus TCA Injection (CCS plus TCA group), and rats receiving a CCS operation plus TUDCA injection (CCS plus TUDCA group). The TMT activities in the serum and in the hepatic subcellular fractions isolated from these experimental rats were determined. The values of Km and Vmax in this he patic enzyme were measured. RESULTS: The activities of liver mitochondrial and microsomal TMTs as well as the Vmax values of TMT were found to be increased significantly in both the CCS plus TCA and the BDO plus TCA groups, compared with the CCS and BDO groups. On the other hand, the Km values of hepatic subcellular TMT were the same in all experimental groups. The serum TMT activity increased significantly in both the CCS plus TCA and the BDO plus TCA groups, compared with the control, CCS and BDO groups. However, these serum and hepatic enzyme activities were the same in the CCS plus TUDCA and the BDO plus TUDCA groups. CONCLUSION: The above results suggest that TCA stimulates the biosynthesis of TMT in the liver. Also, the elevated TMT activity in the serum is thought to be caused by an increase in membrane permeability of hepatocytes from liver cell necrosis caused by TCA.

Effect of Melatonin on Hemolysis Induced by Cyclosporine / 대한신장학회잡지

Hemolysis is one of the side effects of cyclosporine(CsA). Some experimental and clinical data have strongly suggested that CsA-induced hemolysis is resulted from the increased production of free radical species by CsA. Melatonin, a pineal secretory product, acts as a highly efficient free radical scavenger. Thus, melatonin may have a protective effect on the CsA-induced hemolysis. To test this hypothesis, the final concentration of 4.2x106/mL with human erythrocytes was incubated in test tube at 37 degrees C water bath with 1.67 mg/mL of CsA and 72 nmol/mL of melatonin. The degree of hemolysis and the amount of malondialdehyde which gives an indirect index of oxidative injury were measured in group 1 containing only isotonic buffer solution, in group 2 containing only CsA, and in group 3 containing both CsA and melatonin. The degrees of hemolysis in group 2 were higher than those of group 1. The degrees of hemolysis in group 3 were higher than those of group 1, and lower than those of group 2. The amounts of malondialdehyde in group 2 were higher than those of group 1. The amounts of malondialdehyde in group 3 were higher than those of group 1, and lower than those of group 2. These results indicate that the direct contact of erythrocytes with CsA results in free radical mediated hemolysis and the hemolysis by CsA can be prevented with melatonin.

Induction of Hepatic Arylamine N-Methyltransferase by a Taurocholate Load in Rats

PURPOSE: The possible mechanisms of increased arylamine N-methyl- transferase (AMT) activity in cholestatic rat livers and serum were studied. METHODS: Rats were divided into eight groups: rats receiving a sham operation, rats with a bile duct obstruction (BDO) alone (BDO group), rats with a BDO plus taurocholic acid (TCA) injection (BDO plus TCA group), rats with a BDO plus tauroursode oxycholic acid (TUDCA) injection (BDO plus TUDCA group), rats receiving a choledocho-caval shunt (CCS) operation (CCS groups), rats receiving a CCS operation plus TCA injection (CCS plus TCA group), and rats receiving a CCS operation plus TUDCA injection (CCS plus TUDCA group). The AMT activities in the serum and in the hepatic subcellular fractions isolated from the above experimental rats were determined. The values of Km and Vmax in this hepatic enzyme were measured. RESULTS: The activities of liver mitochondrial and microsomal AMTs as well as the Vmax values of AMT, were found to be increased significantly in both the CCS plus TCA group and the BDO plus TCA group compared with the CCS and BDO groups. On the other hand, the values of Km of hepatic subcellular AMT was the same in all experimental groups. The serum AMT activity increased significantly in both the CCS plus TCA group and the BDO plus TCA group compared with control the CCS and BDO group. However, these serum and hepatic enzyme activities were the same in both the CCS plus TUDCA group and the BDO plus TUDCA group. CONCLUSION: The above results suggest that TCA stimulates the biosynthesis of AMT in the liver. Also, the elevated AMT activity in the serum is thought to be caused by an increase in the membrane permeability of hepatocytes from liver cell necrosis caused by TCA.

Mechanism of Renal Oxidative Damage following 4-week Head-down Suspension in Rats

The purpose of this study was to observe the variation of malondialdehyde (MDA), an indirect index of oxidative damage, following 4-week of head-down suspension (HDS) at -45degreein rats as a model of simulated weightlessness. We also measured the activities of antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase for clarifying the mechanisms of renal oxidative damage. MDA was increased (p<0.05) at the 4th week of HDS rats compared to control horizontal positioned rats. Following HDS, the renal activity of SOD was also significantly increased (p<0.01) at the 4th week of HDS whereas the changes of renal GSH-Px and catalase activities were not significantly different from controls. The expression of renal SOD mRNA used by polymerase-chain reaction method showed the similar pattern with the change of renal SOD activity and was more increased (p<0.05) than control horizontal positioned rat. These results indicate that simulated weightlessness induces the augmented SOD gene expression in the kidney which results in increased SOD activity, and thus increased production of MDA due to increased production of hydrogen peroxide. And under this condition, GSH-Px and catalase do not play their protective roles against hydrogen peroxide.

Arylamine Acetyltransferase Activity from a Regenerating Liver after Partial Hepatectomy and from a Cholestatic Liver after Common Bile Duct Ligation in Rats

A study was made of the change in arylamine acetyltransferase(AAT) activity in regenerating and/or cholestatic rat livers. Cytosolic, mitochondrial and microsomal AAT activities were determined over a period of 10 days in rat livers which were regenerating after 70%(median and left lateral lobes) partial hepatectomy and over a period of 42 days in rat livers with cholestasis induced by a common bile duct ligation. The values of Km and Vmax in these hepatic enzymes were measured. Both the cytosolic and the microsomal AAT activities in the regenerating rat livers showed significant increases from the first day to the third day after the partial hepatectomy. However, the mitochondrial AAT activity did not change. The cytosolic and the microsomal AAT activities in the cholestatic rat livers showed a significant increase on the first day and from the first day to the second day, respectively after the ligation; Both the cytosolic and the microsomal AAT activities showed significant decreases from the fourteenth day to the forty-second day after the ligation. However, the mitochondrial AAT activity did not change. The Vmax values of both the cytosolic and the microsomal AAT activity in the regenerating and/or cholestatic rat livers showed significant increases on the first day after the partial hepatectomy and/or the ligation. However, the Vmax values of both the cytosolic and the microsomal AAT activities in the cholestatic rat livers showed significant decreases on the twenty-eighth day after the ligation. On the other hand, the Km values of the above enzymes did not change. In view of the above results, the AAT activity in the regenerating rat liver appears to be due to the enzyme increasing its biosynthesis in the regenerating stage. The AAT activity in the cholestatic rat liver suggests that the enzymes is increasing its biosynthesis in the severe necrotizing stage, but decreasing its biosynthesis severe hepatic dysfunction stage.

Activities of Hepatic Antioxidant Enzymes in Rats during 14 Days of Head-down Suspension as a Model of Simulated Weightlessness

Cells and tissues of human and animal are protected against free radicals by several complex mechanisms including the action of antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase. There had been a few reports that simulated or actual weightlessness induced the decrease in activity of antioxidant enzymes and the increase in lipid peroxidation, The purpose of this study was to observe the time-course variation of antioxidant enzymes activities in rats during 14 days of head-down suspension(HDS) at -45 degrees as a model of simulated weightlessness. During HDS, the hepatic activity of SOD significantly decreased (p<0.05) at 3 day of HDS and then maintained a lower value compared to control horizontal position, GSH-Px activity also significantly decreased (p<0.05) at 3 and 7 day of HDS, thereafter showed a slight increasing trend to control horizontal value. The activity of hepatic catalase increased during HDS and the value at the end of HDS showed significant increase (p<0.05). From these results, there is a possibility that weightlessness induce the increase of oxygen free radicals according to the decrease of some antioxidant enzyme activities. The main scavenger to oxygen free radicals is operated via catalase system in rats during HDS. Therefore, we suggest that it is necessary to administrate the antioxidants for protection of the body against oxygen free radicals during first 1 week after exposure of weightlessness, at least.

Correlation between Levels of Serum Creatinine and Erythrocytic Malondialdehyde(MDA) and Antioxidant Enzymes in Patients with Diabetic Nephropathy / 대한신장학회잡지

Oxygen free radical activity is elevated in diabetes mellitus and has been implicated in the etiology of vascular complications and diabetic nephropathy is a serious microvascular complication in patients with IDDM. Despite intensive investigation, the pathophysiology of diabetic renal disease has not been fully elucidated. However, several clinical and experimental studies have suggested that endothelial dysfunction and changes of peritubular microcirculation might deteriorate renal function in patients with IDDM. We performed this study to examine the oxidative stress and correlation between levels of serum creatinine and erythrocytic MDA, SOD, catalase, GPX in IDDM patients with diabetic nephropathy. Twenty one patients with IDDM(diabetic duration >5 years) and persistent albuminuria(albumin excretion>1000mg/day) and 15 normal healthy controls were investigated prospectively for erythrocytic MDA(thiobarbituric acid assay) and antioxidant enzymes[SOD(Hyland et al.), catalase(Nelson and Kiesow), GPX(Palgia and Valentine)] and correlation to serum creatinine levels. Levels of erythrocytic MDA were significantly higher in patients with diabetic nephropathy than in normal healthy controls(p0.05) and group 2(r=0.12,p>0.05) but there was significant correlation between serum levels of creatine and erythrocytic MDA in group 3(r=0.96, p0.05). We concluded that increased oxidative stress and decreased antioxidative defense mechanism might be factors in the initiation of diabetic nephropathy and the oxidative stress correlated with higher serum levels of creatinine(more than 5mg/dL)(p<0.05).

The protective effect of allopurinol on cholestatic liver injury induced by bile duct ligation

To determine whether oxygen free radicals are responsible for the pathogenesis of the cholestasis induced by ligation of common bile duct (CBD) variables which reflect the hepatic function in the serum, the amount of superoxide radical production, and xanthine oxidase(XO) activity were studied. The activity of serum alanine aminotransferase, bilirubin level in the serum and the amount of superoxide radical production were lower in a CBD ligation with allopurinol treated group than in a CBD ligation without allopurinol treated group. Abnormalities of the microscopic structures were reduced in a CBD ligation with allopurinol treated group than in a CBD ligation without allopurinol treated group. Allopurinol, an inhibitor of XO, prevented the hepatic damage induced by CBD ligation through the inhibition of XO. These experiments demonstrate that oxygen free radicals are responsible for the pathogenesis of the cholestatic liver.

Effect of hypocapnia on extracellular glutamate and glycine concentrations during peri-ischemic period in the rabbit hippocampus

Glutamate (GLU) is a neurotransmitter. Massive release of GLU and glycine (GLY) into the brain's extracellular space may be triggered by ischemia, and may result in acute neuronal lysis or delayed neuronal death. The aim of this study was to evaluate the possible relationship between hyperventilation and the level of GLU and GLY during brain ischemia. Rabbits were anesthetized with halothane and oxygen. Group 1 was allowed to hyperventilate (PaCO2 25-35 mmHg). PaCO2 was maintained throughout the study. Group 2 was a normal control group that maintained normocapnia. Two global cerebral ischemic episodes were produced. Microdialysate was collected during the peri-ischemic and reperfusion periods from the dorsal hippocampus. GLU and GLY concentrations were determined using high-performance liquid chromatography. In the control group, GLU and GLY were significantly elevated during each episode of ischemia; these levels returned to baseline within 10 minutes after reperfusion. In contrast, in the hyperventilation group GLU and GLY concentrations increased during ischemia, but they were not statistically significant. We were able to demonstrate that hypocapnia during periischemic period lowered extracellular GLU and GLY concentrations. These results can explain a part of the protective action of hypocapnia during cerebral ischemia.

Levels of Urinary Neopterin in Patients with Lepromatous Leprosy and Patients with Erythema Nodosum Leprosum / 대한피부과학회지

In lepromatous leprosy, it is generally believed that there is not only defective CMl specific for M. leprae, but also generalized impairment of CMI and in erythema nodosum leprosum, an immune complex-mediated pathogenesis as well cell mediated immune pathogenesis have been proposed. Neopterin is a pyrazinopyrirnidine compound derived from GTP, its raised excretion has been related to activation of T-lymphocyte/macrophage axis. A study was performed to evaluate generalized CMI status in the LL and ENL and to investigate a relationship between levels of urinary neopterin and disease activity. Urinary neopterin was measured by high pressure liquid chromatography in 25 healthy subjects, in 25 patients with LL and in 25 patients with ENL. The results were as follaws 1. Urinary Neopterin levels of patients with LL was 188.9+147.3umol/mol creatinine, which was higher than that of control group(144.8+40.4umol/mol creatinine)(p<0.01). 2. Urinary Neopterin levels of patients with ENL was 884.1+970.5umol/mol creatinine, which was higher than of control group, and patients with LL(p<0.01, p<0.01). 3. Serial measurement of urinary neopterin from 1 week to 13 weeks after treatment of ENL in 4 cases of ENL showed good correlation between urinary neopterin levels and disease activity. In summary, it thus appears that measurement of urine neopterin in leprosy provides generalized CMI status and reliable index for activity of disease.