Oral L-arginine protects against cyclosporine-induced hepatotoxicity in rats. ACTA ACUST UNITED AC. 2008;60:411-419. [PMID: 18583116 DOI: 10.1016/j.etp.2008.04.007]

Ferulic acid exerts a protective effect against cyclosporine-induced liver injury in rats via activation of the Nrf2/HO-1 signaling, suppression of oxidative stress, inflammatory response, and halting the apoptotic cell death

Drug-induced liver injury is one of the main challenges that leads to the withdrawal of several drugs in the clinical setting. Cyclosporine is one of the drugs that its long-term administration exerts devastating effects on the hepatocytes. In the present study, we aimed to evaluate the effect of ferulic acid, a natural compound found in plants, on cyclosporine-mediated hepatotoxicity. Forty-eight male Wistar rats were treated with cyclosporine and/or ferulic acid to evaluate the function as well as the morphology of liver cells. We found that ferulic acid dose-dependently recovered the functional as well as histopathological parameters of liver cells, as revealed by the improvement of hepatocellular vacuolation, portal fibroplasia, and necrosis. Moreover, this phenolic compound was able to restore the balance of the redox system in cyclosporine-treated rats by activating the nuclear factor (NF) erythroid 2-related factor 2 (Nrf2)/hemeoxygenase-1 (HO-1) signaling axis. Of note, the protective effects of ferulic acid against cyclosporine-mediated liver toxicity were not restricted only to induction of the potential antioxidant property, as in the presence of this agent, the expression of pro-inflammatory cytokines such as NF-κB, tumor necrosis factor (TNF)-α, and interleukin-1β was also diminished. Ferulic acid also shifted the equilibrium between the expression levels of proapoptotic to antiapoptotic proteins and thereby prevented the development of cyclosporine-induced liver injury. Overall, these findings highlighted that ferulic acid can reduce cyclosporine-induced liver injury due to its antioxidant properties.

Niclosamide modulates cyclosporin A-induced hepatotoxicity in a mouse model: PPAR-γ and Wnt/β-catenin crosstalk

OBJECTIVES

The aim of this study was to evaluate whether: 1) Wnt/β-catenin signaling is involved in cyclosporin A (CsA)-induced hepatotoxicity, and 2) knockdown of this pathway by niclosamide (NCL) attenuate CsA-induced hepatotoxicity.

METHODS

The experiment was accomplished in 21 days. Adult male mice were randomly distributed into five groups: control group, CsA (25 mg/kg/day) group, CsA + NCL (2.5 mg/kg/day) group, CsA + NCL (5 mg/kg/day) group, and NCL (5 mg/kg/day) group.

RESULTS

NCL showed marked hepatoprotection by significantly decreasing liver enzymes activities and ameliorating the histopathological alterations induced by CsA. Besides, NCL alleviated oxidative stress and inflammation. NCL-treated groups (2.5 and 5 mg/kg) displayed rise in the expression of hepatic peroxisome proliferator-activated receptor-γ (PPAR-γ) by 2.1- and 2.5-fold, respectively. Notably, NCL (2.5 and 5 mg/kg) significantly inhibited Wnt/β-catenin signaling, evidenced by a marked decrease in the hepatic expression of Wnt3a by 54 % and 50 %, frizzled-7 receptor by 50 % and 50 %, β-catenin by 22 % and 49 %, and c-myc by 50 % and 50 %, respectively.

CONCLUSIONS

NCL can be regarded as a potential agent to mitigate CsA-induced hepatotoxicity.

Avocado Seeds-Mediated Alleviation of Cyclosporine A-Induced Hepatotoxicity Involves the Inhibition of Oxidative Stress and Proapoptotic Endoplasmic Reticulum Stress

Previous studies reported disrupted hepatic function and structure following the administration of cyclosporine A (CsA) in humans and animals. Recently, we found that avocado seeds (AvS) ameliorated CsA-induced nephrotoxicity in rats. As a continuation, herein we checked whether AvS could also attenuate CsA-induced hepatotoxicity in rats. Subcutaneous injection of CsA (5 mg/kg) for 7 days triggered hepatotoxicity in rats, as indicated by liver dysfunction, redox imbalance, and histopathological changes. Oral administration of 5% AvS powder for 4 weeks ameliorated CsA-induced hepatotoxicity, as evidenced by (1) decreased levels of liver damage parameters (alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and bilirubin), (2) resumed redox balance in the liver (reduced malondialdehyde (MDA) and increased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)), (3) downregulated hepatic expression of endoplasmic reticulum (ER) stress-related genes (X-box binding protein 1 (XBP1), binding immunoglobulin protein (BIP), C/EBP homologous protein (CHOP)), and apoptosis-related genes (Bax and Casp3), (4) upregulated expression of the anti-apoptotic gene Bcl2, (5) reduced DNA damage, and (6) improved liver histology. These results highlight the ability of AvS to ameliorate CsA-induced hepatotoxicity via the inhibition of oxidative stress and proapoptotic ER stress.

Gryllus bimaculatus De Geer hydrolysates alleviate lipid accumulation, inflammation, and endoplasmic reticulum stress in palmitic acid-treated human hepatoma G2 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Nonalcoholic fatty liver disease (NAFLD) is one of the most common hepatic diseases closely intertwined with saturated fatty acids intake. Therefore, various studies are being conducted to find natural substances to prevent either the onset or progression of NAFLD. According to traditional medicinal literature, it has been reported that Gryllus bimaculatus De Geer (GB) has systemic detoxifying activity; however, the preventive effects of GB on NAFLD have not been elucidated to date.

AIM OF STUDY

To evaluate the potential of GB as a material for the mitigation of NAFLD, we investigated the effects of GB hydrolysates on the hepatic lipid accumulation, inflammation, and endoplasmic reticulum (ER) stress in human hepatoma G2 (Hep G2) cells treated with palmitic acid (PA).

METHODS

Steamed and dried GB was defatted, pulverized, and then lyophilized following hydrolyzation using Neutrase® (GB-N) or Flavourzyme® (GB-F). Hep G2 cells were incubated with GB-N or GB-F at various concentrations (0, 0.25, 0.5, and 1 mg/mL) for 24 h, and then PA was treated for another 24 h.

RESULTS

The GB-N and GB-F significantly prevented the PA-induced intracellular lipid accumulation in the human liver cells (p < 0.05). Moreover, the GB-N and GB-F increased the hepatic cellular viability against the PA-treatment (p < 0.05). In addition, the GB-N and GB-F significantly ameliorated the PA-inducible proinflammatory cytokines mRNA expression, such as tumor necrosis factor-α and interleukin-1β, compared to the PA-treated hepatic cells (p < 0.05). Furthermore, the GB-N and GB-F inhibited the PA-inducible lipogenic mRNA expression, such as fatty acid synthase, sterol regulatory element-binding protein 1c, and peroxisome proliferator-activated receptor-γ (p < 0.05). Moreover, the GB-N and GB-F alleviated the ER stress-related mRNA expression, such as glucose regulatory protein 78 and X-box binding protein increased in PA-treated cells (p < 0.05).

CONCLUSIONS

These results indicate that GB-N and GB-F could be used as materials to prevent the NAFLD onset or progression with alleviating hepatic lipid accumulation, inflammation, and ER stress.

Metformin and silymarin afford protection in cyclosporine A induced hepatorenal toxicity in rat by modulating redox status and inflammation

The use of cyclosporine A (CsA) as an immunosuppressive agent is often limited owing to its hepatotoxic and nephrotoxic properties. The present study was designed to evaluate the protective effect of metformin and silymarin in a rat model of CsA induced hepatorenal toxicity. The study included seven groups of Wistar albino rats (n = 6 per group): normal control, experimental control (CsA alone, 25 mg/kg), CsA + metformin (50 and 500 mg/kg), CsA + silymarin (50 and 200 mg/kg) and CsA + vitamin E (100 mg/kg). All the drugs were given daily for a period of 21 days by oral gavage and their effect was evaluated on serum levels of organ function markers (serum glutamate pyruvate transaminase, serum glutamate oxaloacetate transaminase, bilirubin, urea/blood urea nitrogen, creatinine), markers of oxidative stress (thiobarbituric acid reactive substances, glutathione, superoxide dismutase), inflammation (nitrite, myeloperoxidase, tumour necrosis factor-alpha, prostaglandin E₂ ), apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labelling positivity) in addition to tissue histology, cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) immunoreactivity. Administration of metformin and silymarin along with CsA ameliorated functional damage to liver and kidneys in a dose-dependent manner. Significant and comparable improvement in the tissue levels of oxidative stress, inflammation, apoptotic markers was also observed following treatment with both the test drugs. Normalization of histology scores, as well as COX-2 and iNOS immunoreactivity scores, further strengthened these findings. The hepatoprotective and nephroprotective effects of metformin and silymarin were comparable and matched with that of reference drug, vitamin E. The findings of the present study suggest that both metformin and silymarin have a potential for clinical use in patients receiving long-term CsA treatment to maintain their liver and kidney functions.

The Effects of Short-Term Immunosuppressive Therapy on Redox Parameters in the Livers of Pregnant Wistar Rats

Immunosuppressive drugs are widely used to avoid graft rejection, but they are also known to be strongly hepatotoxic. The goal of the current study was to determine: (i) the immunoexpression of SOD1, CAT, GPX1; (ii) the concentration of MDA, GSH; (iii) the activity of SOD, CAT, GPX, in the native liver of a pregnant female rats undergoing immunosuppressive therapy. The study was based on archival material obtained from Department of Nephrology, Transplantology and Internal Medicine of the Independent Public Clinical Hospital No. 2 at the Pomeranian Medical University in Szczecin, Poland. The study was carried out on 32 female rats exposed to oral administration of immunosuppressants two weeks before and during pregnancy. The percentage of SOD1 immunopositive hepatocytes in rats treated with cyclosporine A, mycophenolate mofetil, everolimus, and glucocorticosteroid was significantly elevated above that of the control rats. The concentration of MDA in the liver of animals exposed to cyclosporine A, everolimus, and glucocorticosteroid was significantly higher than in other groups. Among the groups of dams treated with immunosuppressive drugs, the highest significant concentration of GSH was found in the livers of rats treated with cyclosporine A, mycophenolate mofetil and glucocorticosteroid. Immunosuppressive therapy during pregnancy affects the oxidoreductive balance in the livers of rats, depending on the regimen used.

Hepatoprotective potential of glyceryl trinitrate against chemically induced oxidative stress and hepatic injury in rats

Glyceryl trinitrate (GTN) has been used widely as a potent vasodilator to treat heart conditions, such as angina pectoris and chronic heart failure. This study aims to elucidate the effect of exogenous nitric oxide (NO) administration, using GTN, on carbon tetrachloride (CCl4)-induced oxidative stress and liver injury in rats. The results obtained demonstrated that NO generated by the administration of GTN affords protection against CCl4-induced oxidative stress and liver injury. Administration of CCl4 resulted in a significant ( p < 0.001) increase in lipid peroxidation and tissue damage markers (aspartate and alanine transaminase and lactate dehydrogenase) release in serum. Parallel to these changes, CCl4 also caused downregulation of antioxidant enzymes including glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione-S-transferase (GST), and several fold induction in γ-glutamyl transpeptidase (GGT) activity. Subsequent administration of GTN resulted in significant ( p < 0.001) recovery of GSH-metabolizing enzymes in a dose-dependent manner. Further, administration of NO inhibitor, NG-nitro-l-arginine methyl ester (l-NAME), exacerbated CCl4-induced oxidative tissue injury. Overall, the study suggests that GTN might suppress oxidant-induced tissue injury and hepatotoxicity in rats.

Oxidative Stress and Liver Morphology in Experimental Cyclosporine A-Induced Hepatotoxicity

Cyclosporine A is an immunosuppressive drug used after organ's transplantation. The adverse effects on such organs as kidney or liver may limit its use. Oxidative stress is proposed as one of the mechanisms of organs injury. The study was designed to elucidate CsA-induced changes in liver function, morphology, oxidative stress parameters, and mitochondria in rat's hepatocytes. Male Wistar rats were used: group A (control) receiving physiological saline, group B cyclosporine A in a dose of 15 mg/kg/day subcutaneously, and group C the CsA-vehicle (olive oil). On the 28th day rats were anesthetized. The following biochemical changes were observed in CsA-treated animals: increased levels of ALT, AST, and bilirubin in the serum, statistically significant changes in oxidative stress parameters, and lipid peroxidation products in the liver supernatants: MDA+4HAE, GSH, GSSG, caspase 3 activity, and ADP/ATP, NAD(+)/NADH, and NADP(+)/NADPH ratios. Microscopy of the liver revealed congestion, sinusoidal dilatation, and focal hepatocytes necrosis with mononuclear cell infiltration. Electron microscope revealed marked mitochondrial damage. Biochemical studies indicated that CsA treatment impairs liver function and triggers oxidative stress and redox imbalance in rats hepatocytes. Changes of oxidative stress markers parallel with mitochondrial damage suggest that these mechanisms play a crucial role in the course of CsA hepatotoxicity.

The effects of cyclosporin A and Heteropterys tomentosa on the rat liver

Cyclosporin A (CsA) is a widely employed immunosuppressive drug that is associated with several side effects, among then hepatotoxicity. Heteropterys tomentosa is a Brazilian plant efficient in reducing damage caused by CsA on the rat testis and prostate. The aim of this study was to evaluate the effect of CsA and H. tomentosa (administered isolated or simultaneously) on the liver of Wistar rats. The animals were treated daily with water (control), CsA (15 mg/kg/day), H. tomentosa infusion or CsA+H. tomentosa, for 21 or 56 days. The treatments did not alter liver morphology or cause fibrosis. H. tomentosa administered for 21 days increased the number of hepatocyte nuclei and Kupffer cell volumetric proportion. After 56 days of treatment, H. tomentosa administration did not alter the parameters analyzed. Biochemical plasma dosages and liver stereology showed impairment caused by CsA-treatment after 21 days; these results were not observed after 56 days of treatment. The simultaneous treatment with CsA and H. tomentosa for 21 or 56 days did not alleviate nor accentuate CsA hepatic effects. The present study showed that the 21 days treatment with CsA caused more alteration to the liver than the 56 days treatment; this could be related to hepatic recovery after the long term treatment.

Beneficial effects of quercetin on renal injury and oxidative stress caused by ciprofloxacin in rats: A histological and biochemical study

Ciprofloxacin is a broad-spectrum quinolone antibiotic commonly used in clinical practice. Quercetin is an antioxidant belongs to flavonoid group. It inhibits the production of superoxide anion. In this study, we aimed to evaluate the effects of quercetin on renal injury and oxidative stress caused by ciprofloxacin. Twenty-eight female Wistar albino rats were divided into four groups: control, quercetin (20 mg kg(-1) day(-1) gavage for 21 days), ciprofloxacin (20 mg kg(-1) twice a day intraperitoneally for 10 days), and ciprofloxacin + quercetin. Samples were processed for histological and biochemical evaluations. Malondialdehyde (MDA) and glutathione (GSH) levels, superoxide dismutase (SOD), and catalase (CAT) activities were measured in kidney tissue. The ciprofloxacin group showed histopathological changes such as infiltration, dilatation in tubules, tubular atrophy, reduction of Bowman's space, congestion, hemorrhage, and necrosis. In the ciprofloxacin + quercetin group, these histopathological changes markedly reduced. MDA levels increased in the ciprofloxacin group and decreased in the ciptofloxacin + quercetin group. SOD and CAT activities and GSH levels significantly decreased in the ciprofloxacin group. On the other hand, in the ciprofloxacin + quercetin group, SOD and CAT activities and GSH levels significantly increased with regard to the ciprofloxacin group. We concluded that quercetin has antioxidative and therapeutic effects on renal injury and oxidative stress caused by ciprofloxacin in rats.

Effects of antioxidant agents against cyclosporine-induced hepatotoxicity

BACKGROUND

To investigate the potential protective antioxidant role of ursodeoxycholic acid (UDCA), melatonin, and allopurinol treatment in cyclosporine (CsA)-induced hepatotoxicity.

METHODS

Hepatotoxicity was established in Sprague-Dawley rats by daily administration of CsA. Treatment groups were additionally administered UDCA, melatonin, or allopurinol treatments. Rats that received no CsA and no treatments served as a control group. Liver samples from each group were examined by histopathologic analysis to determine the effects of CsA treatment on liver morphology. Biochemical assays were also used to determine the effect of CsA treatment on liver function, in the presence or absence of UDCA, melatonin, or allopurinol.

RESULTS

CsA treatment induced hepatotoxicity, resulting in sinusoidal dilatation, congestion, infiltration, hydropic degeneration, and loss of glycogen storage in the liver. From a molecular perspective, the CsA treatment increased levels of malondialdehyde (MDA) levels, decreased levels of reduced glutathione and xanthine oxidase, and decreased activities of superoxide dismutase and catalase. The CsA treatment also resulted in decreased serum total antioxidant capacity, whereas alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bilirubin levels, and total oxidant status were increased. Treatment with UDCA, melatonin, or allopurinol reduced the CsA-induced histopathologic changes, as compared with CsA-treated samples. In addition, UDCA, melatonin, or allopurinol treatment mitigated the CsA-induced effects on glutathione and MDA levels, and on superoxide dismutase and catalase activities, as well as reduced the CsA-mediated perturbations in serum levels of total antioxidant capacity, total oxidant status, and alkaline phosphatase.

CONCLUSIONS

UDCA, allopurinol, and melatonin may each help to protect against CsA-induced damage to liver tissues, possibly through effects on the antioxidant system.

Heteropterys tomentosa (A. Juss.) infusion counteracts Cyclosporin a side effects on the ventral prostate

BACKGROUND

Cyclosporin A (CsA) is an immunosuppressive drug widely used in treatment of auto-immune diseases or after organ transplants. However, several side effects are commonly associated with CsA long term intake, some regarding to loss of reproductive organ function due to oxidative damage. Considering that phytotherapy is an important tool often used against oxidative stress, we would like to describe the beneficial effects of Heteropterys tomentosa intake to minimize the damage caused by CsA to the ventral prostate tissue of Wistar rats under laboratorial conditions.

METHODS

Thirty adult Wistar rats (Rattus norvegicus albinus) were divided into: control group (water); CsA group (Cyclosporin A); Ht group (H. tomentosa infusion) and CsA + Ht group (CsA and H. tomentosa infusion). Plasmic levels of hepatotoxicity markers, triglycerides, cholesterol and glucose were quantified. The ventral prostate tissue was analyzed under light microscopy, using stereological, morphometrical and immunohistochemical techniques.

RESULTS

H. tomentosa did not cause any alterations either of the plasmic parameters or of the ventral prostate structure. CsA caused alterations of GOT, total and indirect bilirubin, cholesterol, triglycerides and glucose levels in the plasma; CsA-treated rats showed alterations of the ventral prostate tissue. There were no alterations regarding the plasma levels of GOT, triglycerides and glucose of CsA + Ht animals. The same group also showed normalization of most of the parameters analyzed on the ventral prostate tissue when compared to the CsA group. The treatments did not alter the pattern of AR expression or the apoptotic index of the ventral prostate epithelium.

CONCLUSIONS

The results suggest a protective action of the H. tomentosa infusion against the side effects of CsA on the ventral prostate tissue, which could also be observed with plasmic biochemical parameters.

Protective effect of nitric oxide on hepatopulmonary syndrome from ischemia-reperfusion injury

AIM: To evaluate immunological protection of nitric oxide (NO) in hepatopulmonary syndrome and probable mechanisms of ischemia-reperfusion (IR) injury in rat liver transplantation.

METHODS: Sixty-six healthy male Wistar rats were randomly divided into three groups (11 donor/recipient pairs). In group II, organ preservation solution was lactated Ringer’s solution with heparin 10  000/μL at 4 °C. In groups I and III, the preservation solution added, respectively, L-arginine or N^G-L-arginine methyl ester (L-NAME) (1 mmol/L) based on group II, and recipients were injected with L-arginine or L-NAME (50 mg/kg) in the anhepatic phase. Grafted livers in each group were stored for 6 h and implanted into recipients. Five rats were used for observation of postoperative survival in each group. The other six rats in each group were used to obtain tissue samples, and executed at 3 h and 24 h after transplantation. The levels of alanine aminotransferase (ALT), tumor necrosis factor (TNF)-α and NO metabolites (NOx) were detected, and expression of NO synthase, TNF-α and intercellular adhesion molecule 1 (ICAM-1) was examined by triphosphopyridine nucleotide diaphorase histochemical and immunohistochemical staining.

RESULTS: By supplementing L-arginine to strengthen the NO pathway, a high survival rate was achieved and hepatic function was improved. One-week survival rate of grafted liver recipients in group I was significantly increased (28.8 ± 36.6 d vs 4 ± 1.7 d, P < 0.01) as compared with groups II and III. Serum levels of ALT in group I were 2-7 times less than those in groups II and III (P < 0.01). The cyclic guanosine monophosphate (cGMP) levels in liver tissue and NOx in group I were 3-4 times higher than those of group II after 3 h and 24 h reperfusion, while in group III, they were significantly reduced as compared with those in group II (P < 0.01). The levels of TNF-α in group I were significantly lower than in group II after 3 h and 24 h reperfusion (P < 0.01), while being significantly higher in group III than group II (P < 0.01). Histopathology revealed more severe tissue damage in graft liver and lung tissues, and a more severe inflammatory response of the recipient after using NO synthase inhibitor, while the pathological damage to grafted liver and the recipient’s lung tissues was significantly reduced in group I after 3 h and 24 h reperfusion. A small amount of constitutive NO synthase (cNOS) was expressed in liver endothelial cells after 6 h cold storage, but there was no expression of inducible NO synthase (iNOS). Expression of cNOS was particularly significant in vascular endothelial cells and liver cells at 3 h and 24 h after reperfusion in group II, but expression of iNOS and ICAM-1 was low in group I. There was diffuse strong expression of ICAM-1 and TNF-α in group III at 3 h after reperfusion.

CONCLUSION: The NO/cGMP pathway may be critical in successful organ transplantation, especially in treating hepatopulmonary syndrome during cold IR injury in rat orthotopic liver transplantation.

Protective effect of trapidil and l-arginine against renal and hepatic toxicity induced by cyclosporine in rats

RATIONALE

Cyclosporine A (CsA) leads to renal and liver injury, production of free radicals and nitric oxide (NO) deficiency. This study investigates the possible protective effects of trapidil and L-arginine against CsA-induced tissue injury.

OBJECTIVES

Forty adult male Wistar rats (180 +/- 20 g) were divided into five groups, eight animals in each. The first group served as control, second group served as CsA group, third group served as CsA + trapidil group, fourth group served as CsA + L-arginine group, and fifth group served as CsA + trapidil + L-arginine group. Kidney and liver functions, inflammatory mediators, cytokines, oxidant and antioxidant parameters as well as histopathological studies of renal and liver tissue were assessed in all groups.

MAIN FINDINGS

CsA induced renal and hepatic dysfunction, which was confirmed by laboratory and histopathological examination. Administration of trapidil diminished the renal and liver injury and significantly attenuated the levels of serum creatinine, urea, aspartate aminotransferase (AST), alanine aminotransferase (ALT), interleukin-1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), monocyte chemoattractant protein-1 (MCP-1), and oxidative stress, while it significantly elevated the level of serum nitric oxide and the activity of antioxidative stress. L-Arginine gave the same trend as trapidil, but trapidil effect was more pronounced. Coadministration of trapidil + L-arginine significantly ameliorated the toxic effect of CsA, but did not differ significantly from the effect of trapidil alone.

CONCLUSIONS

Treatment with trapidil or L-arginine diminished the renal and hepatic CsA-induced toxicity. However, the effect of trapidil was more pronounced. Therefore, treatment with trapidil alone may be the most economic and effective as a potential therapeutic agent in CsA injury.

Cyclosporine A: impact on mitochondrial function in endothelial cells

INTRODUCTION

Although cyclosporine A (CSA) is considered to be an efficient immunosuppressive compound in transplantation, vascular side effects like arterial hypertension, neurologic complications and other adverse reactions occur. Interference of CSA with mitochondrial function may be responsible for these side effects.

METHODS

We evaluated the effect of CSA on mitochondrial and glycolytic function by measuring fatty acid oxidation (FAO), activities of respiratory chain complexes (RC) and citratesynthase (CS), lactate/pyruvate-ratios, energy-rich phosphates as well as activities of some glycolytic enzymes in human umbilical vein endothelial cells.

RESULTS

After 48 h of CSA incubation, global FAO, RC-complexes 1 + 3; 4 and 5 as well as CS were compromised while energy charges were not reduced. Lactate/pyruvate-ratios increased; cellular lactate dehydrogenase (LDH)-, hexokinase- and phosphofructokinase-activities were not impaired by CSA. Moderate cellular toxicity, assessed by LDH leakage, appeared only at the highest CSA concentration.

CONCLUSION

Part of CSA toxicity may arise from alterations in mitochondrial function as judged by impaired FAO and respiratory chain enzymes. To some extent, energy balance seems to be maintained by cytosolic energy production. Although only demonstrated for endothelial cells, it is conceivable that such effects will alter energy metabolism of different organs with high oxidative energy demands.

Long-term cyclosporine treatment: evaluation of serum biochemical parameters and histopathological alterations in Wistar rats

The immunosuppressant agent cyclosporine (CsA) is currently used in transplanted patients and in the therapy of autoimmune disorders. CsA treatment has significant acute and chronic side effects on the liver and kidney. However, in the clinical setting, it is difficult to distinguish a direct effect of CsA treatment from other confounding variables, such as allograft rejection and effects due to other drug therapies. In the present study, we assessed for direct associations between CsA immunosuppressive therapy and cytokines levels, kidney and liver functionality, as well as lung histopathological status in rats submitted to chronic CsA treatment without undergoing any transplantation. Male Wistar rats were divided into three groups. The control group received vehicle (corn oil), and treated groups received CsA 5 or 15 mg/kg, by daily gastric gavage during 8 weeks. The results demonstrated that CsA treatment decreases blood levels of interleukins 1α (IL-1α), 1β (IL-1β) and interleukin 2 (IL-2), but does not alter interleukin 6 (IL-6) and IFN-γ levels. Serum biochemical markers of renal (creatinine) and hepatic (SGPT and SGOT) injury/dysfunction did not vary with CsA treatment, despite the presence of small histological alterations, suggesting that the function of these metabolic organs were preserved. Pulmonary histopathological lesions were observed in the CsA groups, and they were attributed to the activation of the local immunoresponse mechanisms by the normal microbiota in immunosuppressive CsA cases. These results suggest that the CsA concentrations administered in our experimental protocol were able to induce immunosuppression in rats without causing nephro and hepatotoxicity.