Detrimental Effects of N-Acetylcysteine Plus Desferoxamine Combination in an Experimental Nephrotic Syndrome Model

Targeting oxidative stress, a crucial challenge in renal transplantation outcome

Disorders characterized by ischemia/reperfusion (I/R) are the most common causes of debilitating diseases and death in stroke, cardiovascular ischemia, acute kidney injury or organ transplantation. In the latter example the I/R step defines both the amplitude of the damages to the graft and the functional recovery outcome. During transplantation the kidney is subjected to blood flow arrest followed by a sudden increase in oxygen supply at the time of reperfusion. This essential clinical protocol causes massive oxidative stress which is at the basis of cell death and tissue damage. The involvement of both reactive oxygen species (ROS) and nitric oxides (NO) has been shown to be a major cause of these cellular damages. In fact, in non-physiological situations, these species escape endogenous antioxidant control and dangerously accumulate in cells. In recent years, the objective has been to find clinical and pharmacological treatments to reduce or prevent the appearance of oxidative stress in ischemic pathologies. This is very relevant because, due to the increasing success of organ transplantation, clinicians are required to use limit organs, the preservation of which against oxidative stress is crucial for a better outcome. This review highlights the key actors in oxidative stress which could represent new pharmacological targets.

The effects of antioxidants on a porcine model of liver hemorrhage

PURPOSE

The aim of this study is to assess the efficacy of the combination of N-acetylcysteine (NAC) and deferoxamine (DFO) in the resuscitation from hemorrhagic shock in a porcine model of bleeding during hepatectomy.

METHODS

Twenty-one pigs were divided randomly to three groups: Sham (S) group, n = 5; fluid (F) resuscitation group, n = 8; and fluid plus NAC plus DFO (NAC&DFO) resuscitation group, n = 8. The animals of groups F and NAC&DFO were subjected to left hepatectomy and controlled hemorrhage from the traumatic liver surface. Shock was established within 10 minutes and maintained for 30 minutes at mean arterial pressure (MAP) of 30 to 40 mm Hg. Resuscitation followed the shock period with crystalloids and colloids. Group NAC&DFO received additionally NAC and DFO in doses of 200 mg/kg and 65 mg/kg, respectively. The total time of the experiment was 6 hours.

RESULTS

Animal weight, blood loss, excised liver mass, and MAP at the end of the shock period were comparable between experimental groups. Group NAC&DFO received significantly lower volume of both crystalloids and colloids (35% and 42% less, respectively) compared to group F. Hepatocellular proliferation (proliferating cell nuclear antigen) was higher in the antioxidant group. Apoptosis, measured by caspase-3, was restored to sham group levels when NAC and DFO were administered.

CONCLUSIONS

Our experimental study showed that coadministration of NAC and DFO during liver hemorrhage can decrease the amounts of fluids needed for resuscitation. Moreover, the antioxidant combination restores the energy dependent apoptosis and proliferation of the hepatocytes.

N-acetylcysteine potentiates doxorubicin-induced ATM and p53 activation in ovarian cancer cells

Doxorubicin has been used clinically to treat various types of cancer, and yet the molecular mode of actions of doxorubicin remains to be fully unraveled. In this study, we investigated the effect of doxorubicin on cultured ovarian cancer cells (CaOV3). MTT assay data showed that doxorubicin inhibits cell proliferation in a time- and dose-dependent manner. Phagokinetic cell motility assay data indicated that doxorubicin inhibits both basal level and EGF-induced cell migration in CaOV3 cells. Confocal microscopic data revealed that doxorubicin induces reorganization of cytoskeletal proteins including actin, tubulin and vimentin. Doxorubicin induces phosphorylation of p53 at Ser15 and 20, acetylation of p53 and ATM activation. Doxorubicin also induces phosphorylation of histone H2AX at Ser139. Interestingly, doxorubicin also inhibits mTOR activity, measured by phosphorylation of S6 ribosomal protein. Pretreatment of CaOV3 cells with antioxidant N-acetylcysteine (NAC), but not pyrrolidine dithiocarbamate (PDTC) potentiates doxorubicin-induced phosphorylation of p53 and ATM. Collectively, we conclude that doxorubicin induces ATM/p53 activation leading to reorganization of cytoskeletal networks, inhibition of mTOR activity, and inhibition of cell proliferation and migration. Our data also suggest that removal of oxidants by antioxidants such as NAC may enhance the efficacy of doxorubicin in vivo.

Effects of N-acetylcysteine, deferoxamine and selenium on doxorubicin-induced hepatotoxicity

The aims of our study were to evaluate the antioxidant defence mechanisms of liver tissue challenged by doxorubucin (DOX) and to compare the possible protective effects of N-acetylcysteine (NAC) (n=10), deferoxamine (DOF) (n=10), DOF+NAC (n= 10) and selenium (n=9) on doxorubicin-induced hepatotoxicity. Fifty-six male rats (Mean weight = 250 ± 50 g) randomly divided into five groups. Animals in study groups were pretreated with a single dose of Dox, which was administered intravenously. Control group (n=7) was treated with intravenous saline injection. Selenium was given intraperitoneally. Blood and urine samples were collected before sacrifice. Liver tissue samples were collected and tissue superoxide dismutase (SOD), glutathione peroxidase (GSH-px), CAT activity, MDA, Zn, iron and copper were determined. DFO decreased lipid peroxidation significantly. DFO and NAC decreased CAT activity significantly. Antioxidant regimes increase SOD activities significantly. DOF and NAC increase GSH-px activities and copper levels significantly. Beneficial effect of selenium seems to result from its stimulation of SOD but not to GSH-px. It has been found that DOF, NAC and selenium have protective effects on Dox-induced hepatocellular damage. DOF+NAC did not result additional benefit.