Anti-arthritic and anti-inflammatory activity of combined pioglitazone and prednisolone on adjuvant-induced arthritis.

The aim of the present study was to evaluate the effect of combined treatment of pioglitazone (PGZ) and prednisolone (PDL) on the progression of adjuvant-induced arthritis in rats. Adjuvant arthritis was induced by single intra-dermal injection of 0.1 ml Freund's complete adjuvant (0.05% w/v Mycobacterium butyricum in mineral oil) into foot pads of left hind paws of Wistar rats of either sex. There were six experimental groups: Group I was healthy animals as control, Group II was arthritic animals without drug treatment, Group III was arthritic animals treated with a standard non-steroidal anti-inflammatory drug aspirin (100 mg/kg), Group IV was arthritic animals received PGZ (10 mg/kg) alone, Group V was arthritic animals received PDL (10 mg/kg) alone, and Group VI was arthritic animals treated with a combined suspension of PGZ and PDL (20 mg/kg). Drugs were administered daily orally at day 0 and continued upto 28th day after induction of arthritis. Induction of arthritis significantly increased hind paw volume (HPV), loss of body weight (BW), enhanced tibiotarsal joint thickness (TJT), and increased plasma tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6 levels. Treatment with aspirin or combined suspension of PGZ and PDL in the arthritic animals produced significant reductions in HPV and TJT, normalized BW, and significantly decreased plasma levels of TNF-α and IL-6. These observations suggest that the combined administration of PGZ and PDL was effective in modulating the inflammatory response and suppress arthritis progression in experimental animal model. These findings may help to improve the treatment of rheumatoid arthritis.

Protective effects of different antioxidants against endosulfan-induced oxidative stress and immunotoxicity in albino rats.

Endosulfan exposure (8 and 16 mg/kg) to rats significantly decreased the activities of superoxide dismutase and catalase, level of reduced glutathione and increased lipid peroxidation. The primary and secondary antiSRBC antibody titers, plaque forming cells counts and delayed hypersensivity reaction, and the TH1 or TH2 cytokines levels were significantly suppressed in a dose dependent manner. L-ascorbic acid and alpha-tocopherol produced a synergistic reversal of oxidative stress parameters following endosulfan exposure. N-acetylcysteine produced significant reversal of altered oxidative stress parameters and immune response after endosulfan exposure. A significant attenuation of the oxidative stress markers and immunotoxicity with a combined therapy of L-ascorbic acid plus alpha-tocopherol and with N-acetylcysteine was clearly demonstrated by the present results.

Role of HSP27 and reduced glutathione in modulating malathion-induced apoptosis of human peripheral blood mononuclear cells: ameliorating effect of N-acetylcysteine and curcumin.

Malathion exerts cholinergic effects at high doses. However, a consequence of low dose (non-cholinergic) exposure causes immunotoxicity and oxidative stress. Hence, this study was designed to find out (i) the cytotoxic and apoptotic effects of cholinergic and non-cholinergic doses of malathion using cultured peripheral blood mononuclear cells (PBMCs) and (ii) the role of GSH and HSP27 and (iii) protective effects of N-acetylcysteine (GSH inducer) and curcumin (HSP27 inducer). In low doses, malathion caused mild depletion of GSH, threefold increase in HSP27 level and a range bound cytotoxicity and apoptosis of PBMC. In contrast, cholinergic dose exposures caused severe GSH depletion and exhibited dose dependent cytotoxicity and necrosis without any significant effect on HSP27 levels. Curcumin increased the levels of HSP27 in PBMC only in presence of low doses and not at high doses of malathion. Both NAC and curcumin were able to prevent malathion-mediated apoptosis of PBMC effectively at non-cholinergic doses and at this concentration of malathion, HSP27 induction keeps apoptosis and GSH depletion under control. Also NAC and curcumin may act as potential therapeutic agents to prevent malathion-induced immunotoxicity.

Endosulfan-induced apoptosis and glutathione depletion in human peripheral blood mononuclear cells: Attenuation by N-acetylcysteine.

Present study investigated whether endosulfan, an organochlorine pesticide is able to deplete glutathione (GSH) and induce apoptosis in human peripheral blood mononuclear cells (PBMC) in vitro. The role of oxidative stress in the induction of apoptosis was also evaluated by the measurement of the GSH level in cell lysate. The protective role of N-acetylcysteine (NAC) on endosulfan-induced apoptosis was also studied. Isolated human PBMC were exposed to increasing concentrations (0-100 microM) of endosulfan (alpha/beta at 70:30 mixture) alone and in combination with NAC (20 microM) up to 24 h. Apoptotic cell death was determined by Annexin-V Cy3.18 binding and DNA fragmentation assays. Cellular GSH level was measured using dithionitrobenzene. Endosulfan at low concentrations, i.e., 5 and 10 microM, did not cause significant death during 6 h/12 h incubation, whereas a concentration-dependent cell death was observed at 24 h. DNA fragmentation analysis revealed no appreciable difference between control cells and 5 microM/10 microM endosulfan treated cells, where only high molecular weight DNA band was observed. Significant ladder formation was observed at higher concentration, which is indicative of apoptotic cell death. Intracellular GSH levels decreased significantly in endosulfan-treated cells in a dose-dependent manner, showing a close correlation between oxidative stress and degree of apoptosis of PBMC. Cotreatment with NAC attenuated GSH depletion as well as apoptosis. Our results provide experimental evidence of involvement of oxidative stress in endosulfan-mediated apoptosis in human PBMC in vitro.

Melatonin treatment prevents modulation of cell-mediated immune response induced by propoxur in rats.

The effect of melatonin, a major secretory product of the pineal gland, in attenuation of propoxur (2-isopropoxy phenyl N-methyl carbamate)-induced modulation of cell-mediated immune (CMI) response was studied in rats. Male Wistar albino rats were exposed to propoxur (a widely used pesticide) orally (10 mg/kg) and/or melatonin (10 mg/kg) orally for 4 weeks. CMI was measured by delayed-type hypersensitivity (DTH), leucocyte and macrophage migration inhibition (LMI and MMI) responses and estimation of cytokines TNF-alpha and IFN-gamma levels. Rats exposed to propoxur for 4 weeks showed significant decrease in DTH, LMI and MMI responses. Propoxur also suppressed TNF-alpha and IFN-gamma production significantly. Administration of melatonin alone caused a significant increase in DTH response. Although there were no changes in the LMI and MMI response, the cytokine levels were significantly increased, as compared to control. Co-administration of melatonin along with propoxur significantly nullified the effect of the pesticide on the CMI response, except DTH and reversed levels of cytokines to near control/normal values. Thus, melatonin treatment considerably attenuated immunomodulation caused by sub-chronic treatment of propoxur in experimental animals.

Protective effects of dietary ginger (Zingiber officinales Rosc.) on lindane-induced oxidative stress in rats.

The protective effect of dietary feeding of Zingiber officinales Rosc. (ginger) against lindane-induced oxidative stress was investigated in male albino rats. Oxidative stress was monitored by estimating the extent of lipid peroxidation, activities of the oxygen free radical (OFR) scavenging enzymes superoxide dismutase (SOD) and catalase (CAT) and the status of the glutathione redox cycle antioxidants. Lindane administration (30 mg/kg bw orally for 4 weeks) was associated with enhanced lipid peroxidation and compromised antioxidant defenses in rats fed a normal diet. Concomitant dietary feeding of ginger (1%w/w) significantly attenuated lindane-induced lipid peroxidation, accompanied by modulation of OFR scavenging enzymes as well as reduced glutathione (GSH) and the GSH dependent enzymes glutathione peroxidase (Gpx), glutathione reductase (GR) and glutathione-S-transferase (GST) in these rats. These findings suggest that a diet containing naturally occurring compounds is effective in exerting protective effects by modulating oxidative stress.

Alteration of superoxide- and nitric oxide-mediated antimicrobial function of macrophages by in vivo cocaine exposure.

Cocaine is a popular drug of abuse and despite impressive advances in the understanding of its physiological, pharmacological, and toxic effects, its mechanism of immunosuppression at the cellular level is not well understood. In this paper we report the role of effector molecules like superoxide and nitric oxide in the antibacterial function of macrophages exposed to acute and chronic doses of cocaine in vivo. Bacterial killing by acute cocaine-exposed macrophages (ACE-Mphis) increased significantly, with a concomitant rise in respiratory burst and generation of superoxide and nitric oxide, compared with control macrophages. In contrast, chronic cocaine-exposed macrophages (CCE-Mphis) exhibited limited antimicrobial activity, which correlated closely with diminished respiratory burst and reduced production of superoxide and nitric oxide. Further, a killing assay was carried out in the presence of N(G)-methyl-L-arginine acetate, an inhibitor of iNOS, to evaluate the role of nitric oxide in the killing process. The results obtained indicate that while about 30% killing of input bacteria by control and ACE-Mphis was attributable to NO-mediated killing, only about 6% killing from NO was found with CCE-Mphis. The findings indicate that acute exposure to cocaine possibly caused upregulation of enzymes responsible for the generation of ROI (reactive oxygen intermediates) and RNI (reactive nitrogen intermediates), leading to enhanced antimicrobial function. On the other hand, chronic exposure to cocaine impaired the oxygen-dependent microbicidal capacity of macrophages, possibly through impaired expression of enzymes responsible for ROI and RNI formation. Proinflammatory cytokines may play a key role in cocaine-mediated immunosuppression, since exposure of macrophages to cocaine impairs the ability of the cells to produce these cytokines.

Comparative effect of topical application of lindane and permethrin on oxidative stress parameters in adult scabies patients.

OBJECTIVES: The insecticides lindane and permethrin are commonly used for treatment of scabies. Animal studies have shown the presence of insecticide induced oxidative stress. Hence, this study was undertaken to assess and compare the effects of topical application of lindane and permethrin on oxidative stress parameters in scabies patients. DESIGN AND METHODS: Patients were alternatively assigned to treatment by either 1% lindane lotion or 5% permethrin cream. Blood samples were collected before and 12-14 h after the application of the drugs and evaluated for oxidative stress parameters and compared with healthy controls. RESULTS: Serum malondialdehyde (MDA) levels, erythrocyte superoxide dismutase (SOD) and catalase (CAT) activity were significantly increased while blood glutathione (GSH) levels were significantly decreased in the lindane group as compared to controls and the permethrin group. The permethrin treated group showed a non significant alteration in the oxidative stress parameters. CONCLUSION: Topical application of lindane induced significant oxidative stress as compared to permethrin which appears to be a safer option for the treatment of scabies.

Impact of oral vitamin E supplementation on oxidative stress & lipid peroxidation in patients with polymorphous light eruption.

BACKGROUND & OBJECTIVES: Polymorphous light eruption (PMLE) is a photo-induced disease which clinically manifests in the form of pruritic eruptions on sun/light exposed parts. Little is known about lipid peroxidation and free radical scavengers in patients during PMLE. The present study was therefore undertaken to evaluate oxidative stress and levels of antioxidant enzymes in patients of PMLE. METHODS: The PMLE was diagnosed clinically by a consultant dermatologist and validated independently by another and through histopathologic findings. Blood samples were collected on day 1 and patients were given oral vitamin E supplementation (400 mg OD) along with topical sunscreen and advice for photo-protection. Samples were collected again after one week. The blood samples were evaluated for lipid peroxidation, oxygen free radical (OFR) scavenging enzymes, glutathione (GSH) and related enzymes such as glutathione reductase (GR), glutathione peroxidase (GPx), gamma glutamyl transpeptidase (GGT) and glutathione- S-transferase (GST) in erythrocytes and compared with healthy controls. RESULTS: The serum malondialdehyde (MDA) level was higher and GSH level was lower in PMLE cases as compared to controls. There was a significant decrease in superoxide dismutase (SOD) activity while activities of catalase (CAT) and glutathione related enzymes were increased in PMLE cases. Administration of oral vitamin E for one week, along with photoprotection resulted in a significant decrease in MDA levels and activities of all others enzymes except SOD. The GSH was replenished and returned to normal. INTERPRETATION & CONCLUSION: Oxidative stress and differential modulation of antioxidant enzymes in PMLE might play a pathogenic role in humans, which supports the incorporation of antioxidant drugs in the treatment protocol of the disease.

Immunotoxicity of phosphamidon following subchronic exposure in albino rats.

Effect of subchronic doses of phosphamidon exposure on humoral and cell mediated immune (CMI) responses were studied in male albino rats using SRBC, ovalbumin and KLH as antigens. Humoral immune responses were assessed by estimating antibody titre against antigen and splenic plaque forming cells (PFC) assay. CMI responses were studied by using leucocyte migration inhibition (LMI), macrophage migration inhibition (MMI) and delayed type hypersensitivity (DTH) response. Results obtained in the present study revealed marked suppression of humoral and CMI responses in a dose dependent pattern. Hence, suppression of immune responses by phosphamidon even at subchronic doses is clearly an important aspect for its safety evaluation.

Lindane-induced immunological alterations in human poisoning cases.

OBJECTIVES: Evaluation of immunological alterations in the blood of human lindane poisoning cases. DESIGN AND METHODS: Serum IgG, IgM, IgA, IgE, IL-2, IL-4, TNF-alpha, and IFN-gamma levels were measured using immunoassay in 20 human cases of lindane poisoning. The presence of lindane in blood was confirmed by HPLC. RESULTS: Serum IL-2, IL-4, and TNF-alpha levels were significantly raised with decrease in IFN-gamma levels in the lindane-exposed cases. Immunoglobulin levels were not altered. CONCLUSIONS: The results suggest that lindane exposure at chronically high levels affects cytokine levels in humans and indicates the severity of immunotoxicity.