Mohamed A. Dkhil

The protective effect of flaxseed oil on lead acetate-induced renal toxicity in rats

Lead is a toxic metal inducing many destructive effects leading to a broad range of physiological, biochemical, and neurological dysfunctions in humans. Here, we investigated the effects of flaxseed oil (1000 mg/kg) on the outcome of renal cytotoxicity induced by lead acetate (20mg/kg) in male rats. Lead induced injury of the renal tissue. This was evidenced (i) as increases in lead concentration in the kidney, (ii) as increases in the histopathological damage of the renal tissue, (iii) as increases in uric acid, urea and creatinine, (iv) as increases in lipid peroxidation, nitric oxide and reactive oxygen species, and (v) as lowered glutathione levels and decreased activities of catalase and superoxide dismutase, glutathione reductase, glutathione-S-transferase, and glutathione peroxidase, respectively. All these lead-induced parameters were significantly altered during flaxseed oil treatment. Therefore, our study suggests the role of flaxseed oil in limiting renal cytotoxicity-induced by lead acetate as a model for lead toxicity.

Testosterone-induced upregulation of miRNAs in the female mouse liver.

Testosterone (T) regulates expression of protein-encoding genes directly through androgen receptor (AR) targeting androgen response element (ARE) in gene promoters or indirectly through non-genotropic mechanisms, but only limited information is available about T effects on expression of gene-regulatory non-coding miRNAs. Here, we investigate the effect of T on miRNA expression profiles in the female mouse liver using miRXplore microarrays and quantitative RT-PCR. T treatment for 3 weeks induced upregulation of the 6 miRNAs miR-22, miR-690, miR-122, let-7A, miR-30D and let-7D, reaching maximal expression at different time-points during T treatment. This upregulation was transient, i.e. it disappeared after T withdrawal for 12 weeks, and it was rather robust since it was not essentially affected by blood-stage infections with Plasmodium chabaudi malaria. In silico analysis revealed an ARE in the miR-122 promoter, while the other 5 miRNAs did not contain any ARE in their 2000bp promoters. The T-induced upregulation of the 6 miRNAs coincided with a downregulation of some of their target protein-encoding genes, the majority of which did incidentally not contain any ARE in their promoters. T treatment did not affect expression of AR and estrogen receptor beta (ERbeta), but significantly downregulated the miR-22 target genes ERalpha and aromatase. This downregulation is presumably not caused by T after its aromatase-mediated conversion to E(2) through ER, but rather by the T-induced upregulation of miR-22. Collectively, our data suggest that T can regulate expression of distinct miRNAs in vivo by both genotropic and non-genotropic mechanisms.

Testosterone Suppresses Protective Responses of the Liver to Blood-Stage Malaria

ABSTRACT Testosterone induces a lethal outcome in otherwise self-healing blood-stage malaria caused by Plasmodium chabaudi. Here, we examine possible testosterone effects on the antimalaria effectors spleen and liver in female C57BL/6 mice. Self-healing malaria activates gating mechanisms in the spleen and liver that lead to a dramatic reduction in trapping activity, as measured by quantifying the uptake of 3-μm-diameter fluorescent polystyrol particles. However, testosterone delays malaria-induced closing of the liver, but not the spleen. Coincidently, testosterone causes an ∼3- to 28-fold depression of the mRNA levels of nine malaria-responsive genes, out of 299 genes tested, only in the liver and not in the spleen, as shown by cDNA arrays and Northern blotting. Among these are the genes encoding plasminogen activator inhibitor (PAI1) and hydroxysteroid sulfotransferase (STA2). STA2, which detoxifies bile acids, is suppressed 10-fold by malaria and an additional 28-fold by testosterone, suggesting a severe perturbation of bile acid metabolism. PAI1 is protective against malaria, since disruption of the PAI1 gene results in partial loss of the ability to control the course of P. chabaudi infections. Collectively, our data indicate that the liver rather than the spleen is a major target organ for testosterone-mediated suppression of resistance against blood-stage malaria.

Anticoccidial and antiinflammatory activity of garlic in murine Eimeria papillata infections

Coccidiosis with the protozoan parasite Eimeria as the infectious agent causes enormous economic losses, particularly in poultry farms. Here, we investigated the effects of garlic on the outcome of coccidiosis caused by Eimeria papillata in male Balb/c mice. The data showed that mice infected with E. papillata revealed an output of 3260 ± 680 oocysts per gram faeces on day 4 p.i.. This output is significantly decreased to 1820 ± 415 oocysts in garlic-treated mice. Infection also induced inflammation and injury of the liver. This was evidenced (i) as increases in inflammatory cellular infiltrations, dilated sinusoids, and vacuolated hepatocytes, (ii) as increased mRNA levels of inducible nitric oxide synthase (iNOS) and of the cytokines interferon gamma (IFN-γ), and interleukin-6 (IL-6), (iii) as increased plasma levels of alanine and aspartate aminotransferases, alkaline phosphatase, γ-glutamyl transferase and total bilirubin, (iv) as increased production of nitric oxide derived products (nitrite/nitrate) and malondialdehyde, and (v) as lowered glutathione levels and decreased activities of catalase and superoxide dismutase, respectively. All these infection-induced parameters were significantly less altered during garlic treatment. In particular, garlic counteracted the E. papillata-induced loss of glutathione and the activities of catalase and superoxide dismutase. Our data indicated that garlic treatment significantly attenuated inflammation and injury of the liver induced by E. papillata infections.

The Redox Status in Rats Treated with Flaxseed Oil and Lead-Induced Hepatotoxicity

Lead is a persistent environmental pollutant, and its toxicity continues to be a major health problem due to its interference with natural environment. In the present study, we have evaluated the effect of flaxseed oil on lead acetate-mediated hepatic oxidative stress and toxicity in rats. Lead acetate enhanced lipid peroxidation and nitric oxide production in both serum and liver with concomitant reduction in glutathione, catalase, superoxide dismutase, glutathione reductase, glutathione-S-transferase, and glutathione peroxidase activities, these findings were associated with DNA fragmentation. In addition, lead acetate caused liver injury as indicated by histopathological changed of the liver with an elevation in total bilirubin, serum alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transpeptidase, and alkaline phosphatase. Treatment of rats with flaxseed oil resulted in marked improvement in most of the studied parameters as well as histopathological features. On the basis of the above results it can hypothesized that flaxseed oil is a natural product can be protect against lead acetate-mediated hepatic cytotoxicity.

Massive Destruction of Malaria-Parasitized Red Blood Cells despite Spleen Closure

ABSTRACT It is currently accepted that malaria-parasitized red blood cells (pRBC) are eliminated, like senescent erythrocytes, phagocytically by macrophages in the red pulp of the spleen. Here, however, we show that self-healing Plasmodium chabaudi malaria activates spleen closure in C57BL/6 mice. Confocal laser scanning microscopy revealed that spleen closing was manifested by elimination of entry into the red pulp of 3-μm polystyrol particles, pRBC, and nonparasitized red blood cells but not of bovine serum albumin. This spleen closure did not reflect a reduction in the number of phagocytic cells, as shown by flow cytometry, whereas marginal zone macrophages (MZM) were lost and red pulp macrophages entered the white pulp. Splenic trapping of pBRC was strongly reduced in the absence of MZM and marginal metallophilic macrophages (MMM), as it is in noninfected mice with a disrupted lymphotoxin β receptor (LTβR−/−), and it was still significantly reduced when the number of MZM and MMM was diminished, as in tumor necrosis factor alpha-deficient (TNF-α−/−) mice. Moreover, mice deficient in TNF-α, tumor necrosis factor receptor I (TNFRI−/−), and LTβR exhibited progressive impairment in malaria-induced spleen closing. Treatment of C57BL/6 mice with TNF-α induced loss of MZM and spleen closing by about 20%. Our data indicate that TNF/TNFRI signaling is involved in regulating malaria-induced spleen closure, which is maximal during crisis, when parasitemia declines more than 100-fold. Consequently, the vast majority of pRBC cannot be destroyed by the spleen during crisis, suggesting that the known sophisticated sequestration system of Plasmodium parasites did not evolve to avoid splenic clearance.

The potential protective role of Physalis peruviana L. fruit in cadmium-induced hepatotoxicity and nephrotoxicity

This study aimed to investigate the potential protective role of Physalis peruviana L. (family Solanaceae) against cadmium-induced hepatorenal toxicity in Wistar rats. Herein, cadmium chloride (CdCl2) (6.5 mg/kg bwt/day) was intraperitoneally injected for 5 days, and methanolic extract of physalis (MEPh) was pre-administered to a group of Cd-treated rats by an oral administration at a daily dose of 200 mg/kg bwt for 5 days. The findings revealed that CdCl2 injection induced significant decreases in kidney weight and kidney index. Cadmium intoxication increased the activities of liver enzymes and the bilirubin level, in addition to the levels of uric acid, urea and creatinine were increased in the serum. The pre-administration of MEPh alleviated hepatorenal toxicity in Cd-treated rats. Physalis was noted to play a good hepatorenal protective role, reducing lipid peroxidation, nitric oxide, and enhancing enzymatic activities and non-enzymatic antioxidant molecule, glutathione, in hepatic and renal tissues of Cd-treated rats. Moreover, physalis treatment was able to reverse the histopathological changes in liver and kidney tissues and also increased the expression of Bcl-2 protein in liver and kidney of rats. Overall, the results showed that MEPh can induce antioxidant and anti-apoptotic effects and also exerts beneficial effects for the treatment of Cd-induced hepatorenal toxicity.

Dietary Selenium in Adjuvant Therapy of Viral and Bacterial Infections

Viral and bacterial infections are often associated with deficiencies in macronutrients and micronutrients, including the essential trace element selenium. In selenium deficiency, benign strains of Coxsackie and influenza viruses can mutate to highly pathogenic strains. Dietary supplementation to provide adequate or supranutritional selenium supply has been proposed to confer health benefits for patients suffering from some viral diseases, most notably with respect to HIV and influenza A virus (IAV) infections. In addition, selenium-containing multimicronutrient supplements improved several clinical and lifestyle variables in patients coinfected with HIV and Mycobacterium tuberculosis. Selenium status may affect the function of cells of both adaptive and innate immunity. Supranutritional selenium promotes proliferation and favors differentiation of naive CD4-positive T lymphocytes toward T helper 1 cells, thus supporting the acute cellular immune response, whereas excessive activation of the immune system and ensuing host tissue damage are counteracted through directing macrophages toward the M2 phenotype. This review provides an up-to-date overview on selenium in infectious diseases caused by viruses (e.g., HIV, IAV, hepatitis C virus, poliovirus, West Nile virus) and bacteria (e.g., M. tuberculosis, Helicobacter pylori). Data from epidemiologic studies and intervention trials, with selenium alone or in combination with other micronutrients, and animal experiments are discussed against the background of dietary selenium requirements to alter immune functions.

Piroxicam-induced hepatic and renal histopathological changes in mice

Piroxicam is a non-steroidal anti-inflammatory drug widely used in rheumatic diseases. The aim of this study was to investigate Piroxicam-induced histopathological changes in livers and kidneys of male albino mice. Methods: Animals were classified into a control group and 4 treated groups. Piroxicam was injected intraperitoneally using 0.3 mg/kg every day for four weeks. Each week a group of mice was sacrificed. Liver and kidneys were obtained for histological and histochemical examination. Animals were classified into a control group and 4 treated groups. Piroxicam was injected intraperitoneally using 0.3 mg/kg every day for four weeks. Each week a group of mice was sacrificed. Liver and kidneys were obtained for histological and histochemical examination. Results: Liver sections appeared with inflammatory cellular infiltration, vacuolated hepatocytes, dilated sinusoids, and increased number of Kupffer cells. Kidney sections appeared with some cellular inflammations. The glomeruli were shrunk resulting in widening of the urinary space. Oedema and vacuolations were noticed in the tubular cells. There was a positive correlation between these pathological changes and the increased treatment periods. Histochemical staining revealed that glycogen and protein contents had decreased in the hepatocytes. This depletion worsened gradually in liver cells after two, three, and four weeks. Similar depletion of the glycogen content was observed in kidney tissue. However, protein content appeared to be slightly decreased in the kidney tubules and glomeruli. Incensement of coarse chromatin in the nuclei of hepatocytes, Kupffer cells and most inflammatory cells were detected by Fuelgen method. Kidney tissues appeared with a severe decrease in coarse chromatin in the nuclei. Liver sections appeared with inflammatory cellular infiltration, vacuolated hepatocytes, dilated sinusoids, and increased number of Kupffer cells. Kidney sections appeared with some cellular inflammations. The glomeruli were shrunk resulting in widening of the urinary space. Oedema and vacuolations were noticed in the tubular cells. There was a positive correlation between these pathological changes and the increased treatment periods. Histochemical staining revealed that glycogen and protein contents had decreased in the hepatocytes. This depletion worsened gradually in liver cells after two, three, and four weeks. Similar depletion of the glycogen content was observed in kidney tissue. However, protein content appeared to be slightly decreased in the kidney tubules and glomeruli. Incensement of coarse chromatin in the nuclei of hepatocytes, Kupffer cells and most inflammatory cells were detected by Fuelgen method. Kidney tissues appeared with a severe decrease in coarse chromatin in the nuclei. Conclusion: Piroxicam has a time-dependent toxic effect on both liver and kidney tissues.

Protective role of flaxseed oil against lead acetate induced oxidative stress in testes of adult rats

Although the delayed-type hypersensitivity (DTH) skin reaction to tuberculin is used worldwide for tuberculosis (TB) detection, it has poor diagnostic specificity due to the presence of common antigens in tuberculin shared by many mycobacterial species. The problem is noticed, especially in countries where the Bacillus Calmette-Gue´rin (BCG) vaccination is widely practiced. Thus, a new skin test antigen specific for the diagnosis of Mycobacterium tuberculosis (MTB) infection is urgently needed. CFP-10, a mycobacterial secretary protein that is absent in Mycobacterium bovis BCG and most other mycobacterial species including Mycobacterium avium, Mycobacterium intracellulare, has been shown to elicit cellular immune responses in MTB infected individuals and can be a good candidate for MTB specific diagnosis. We prepared recombinant MTB CFP-10, rCFP-10, and its utility as specific antigen for TB diagnosis was evaluated by skin testing in guinea pigs sensitized with M . tuberculosis, M. bovis, and M. bovis BCG. Our results show that the purified MTB rCFP-10 antigen elicits a positive skin response only in the guinea pigs sensitized with M. tuberculosis and M. bovis , and not in the animals sensitized with M. bovis BCG vaccine. The data presented in this study supports further testing of the use rCFP-10 as the specific antigen in the skin test for the diagnosis of MTB infection in humans. Key words : Recombinant CFP-10 protein, skin test, delayed-type hypersensitivity, tuberculosis infection, Mycobacterium tuberculosis, Mycobacterium bovis, Bacillus Calmette-Gue´rin.