Hamdy A.A. Aly

Testicular toxicity effects of magnetic field exposure and prophylactic role of coenzyme Q10 and L-carnitine in mice.

The protective effect of L-carnitine or coenzyme Q10 (CoQ10) against high magnetic field (20 mT) induced testicular toxicity in mice were evaluated. Animals were injected with L-carnitine (200 mg kg(-1), i.p.) or CoQ10 (200 mg kg(-1), p.o.) 1h before exposure to fractionated doses (30 min per day, three times per week for 2 weeks) or acute dose (3h) of magnetic field. Total sperm count, motility, daily sperm production, and testicular LDH-X activity as well as histopathological examination were investigated. Exposure of mice to fractionated doses of magnetic field caused a significant decrease in sperm count, motility, daily sperm production, and LDH-X activity, which was more pronounced than that of acute dose. Moreover, a marked testicular histopathological changes were observed after exposure to fractionated doses of magnetic field. Pretreatment of mice with L-carnitine or CoQ10 1h before exposure to magnetic field caused a significant recovery of mice testes damage induced by high magnetic field (20 mT).

Cytotoxicity and mitochondrial dysfunction of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in isolated rat hepatocytes.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental contaminant that induces hepatic and extrahepatic oxidative stress and the mechanisms of TCDD-induced reactive oxygen species are not fully investigated. Moreover, the potential toxicity of TCDD in isolated rat hepatocytes is not fully explored. The aim of the current study was to explore the possible cytotoxic effect of TCDD on primary rat hepatocytes and to explore the impact of mitochondria in TCDD-induced toxicity. Hepatocytes were isolated from adult rat liver and incubated with 0, 5, 10 or 15 nM of TCDD for 24, 48 and 72 h. Cell viability, lactate dehydrogenase (LDH) leakage into media along with reactive oxygen species (ROS) generation and hydrogen peroxide (H(2)O(2)) production, mitochondrial membrane potential (Deltapsi(m)), superoxide dismutase (SOD), catalse (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), total thiol contents, hepatic aryl hydrocarbon hydroxylase (AHH), and ethoxyresorufin O-deethylase (EROD) were performed in hepatocytes. In addition, superoxide anion generation, lipid peroxidation (LPO), mitochondrial protein carbonyl content and respiratory chain complexes II and IV were assayed in hepatocyte mitochondria. Cell viability was significantly decreased while LDH leakage into media was significantly increased in a dose and time related manner. ROS generation and H(2)O(2) production along with EROD and AHH activities were significantly increased in hepatocytes in the same pattern. The antioxidant enzymes SOD, CAT, GPx and GR and the non-enzymatic protein thiols, in addition to Deltapsi(m) were significantly decreased in hepatocytes in a concentration and time dependent pattern. On the other side, mitochondrial superoxide anion along with LPO and mitochondrial protein carbonyl content were significantly increased while the respiratory chain complexes II and IV activities were significantly decreased in hepatocyte mitochondria. This effect may lead to disruption in the functional integrity of hepatocytes and hepatocyte mitochondria. In conclusion, our data clearly show that TCDD induces hepatocyte toxicity and mitochondrial dysfunction by a mechanism involving generation of ROS. Mitochondria might be the primary source of (or at least contribute to) the oxidative stress response and resulting toxicological outcomes elicited by TCDD.

Aroclor 1254 impairs spermatogenesis and induces oxidative stress in rat testicular mitochondria.

Aroclor 1254 (A1254) has been shown to have potential testicular toxicity. The mechanism of action of A1254 on male reproduction is not clear. The present study was designed to investigate the potential toxicity of A1254 on rat spermatogenesis. Oxidative stress was also assessed in testicular mitochondria as an underlying mechanism. Adult male Wistar rats were injected with A1254 (0, 0.75, 1.5 or 3mg/kg/day i.p.) or with vehicle (corn oil) for 20 consecutive days. A1254 at doses of 1.5 and 3mg/kg/day resulted in a significant decrease in body weight, testes weight, epididymal and relative epididymal weight. Similarly, the relative testis weight was significantly decreased at 3mg/kg/day. Sperm count, motility and daily sperm production were significantly decreased at 1.5 and 3mg/kg/day. The same two doses significantly inhibited the activities of testicular mitochondrial CAT, GPx and GR while the activity of SOD was significantly decreased by 0.75, 1.5 and 3mg/kg/day. The levels of H(2)O(2) generation and LPO were significantly increased in mitochondria in a dose-related pattern. GSH and Vit C were significantly decreased at 0.75, 1.5 and 3mg/kg/day. In conclusion, A1254 impairs spermatogenesis as evidenced, at least partly, by induction of oxidative stress in testicular mitochondria.

Taurine reverses endosulfan-induced oxidative stress and apoptosis in adult rat testis

The present study was aimed to investigate the mechanistic aspect of endosulfan toxicity and its protection by taurine in rat testes. Pre-treatment with taurine (100 mg/kg/day) significantly reversed the decrease in testes weight, and the reduction in sperm count, motility, viability and daily sperm production in endosulfan (5 mg/kg/day)-treated rats. Sperm chromatin integrity and epididymal L-carnitine were markedly decreased by endosulfan treatment. Endosulfan significantly decreased the level of serum testosterone and testicular 3β-HSD, 17β-HSD, G6PDH and LDH-X. Sperm Δψm and mitochondrial cytochrome c content were significantly decreased after endosulfan. Testicular caspases-3, -8 and -9 activities were significantly increased but taurine showed significant protection from endosulfan-induced apoptosis. Oxidative stress was induced by endosulfan treatment as evidenced by increased H2O2 level and LPO and decreased the antioxidant enzymes SOD, CAT and GPx activities and GSH content. These alterations were effectively prevented by taurine pre-treatment. In conclusion, endosulfan decreases rat testes weight, and inhibits spermatogenesis and steroidogenesis. It induces oxidative stress and apoptosis by possible mechanisms of both mitochondria and non-mitochondria pathways. These data provide insight into the mode of action of endosulfan-induced toxicity and the beneficial role provided by taurine to counteract endosulfan-induced oxidative stress and apoptosis in rat testis.

Abrogation of cisplatin-induced nephrotoxicity in mice by alpha lipoic acid through ameliorating oxidative stress and enhancing gene expression of antioxidant enzymes

Cisplatin is chemotherapeutic drug used in treatment of malignancies. However, its clinical utility is limited by nephrotoxicity. The purpose of present study is to investigate biochemical and molecular effects of alpha lipoic acid (ALA) to protect against cisplatin-induced nephrotoxicity in mice. Cisplatin (12 mg/kg/day) was administered i.p. for 4 days. Group of mice were given ALA (20 mg/kg/day) for 18 days. Another set were administered ALA for 4 days before and 14 days after cisplatin intoxication. The results obtained revealed that kidney/body weight ratio of cisplatin-treated mice was increased by +40%. ALA intake declined the ratio by -19%. Serum creatinine and urea levels were increased in cisplatin-treated mice by +375% and +69%, respectively. These changes were moved to normalcy upon ALA intake. Cisplatin treatment elevated malondialdehyde (MDA) by 27 fold and declined reduced glutathione (GSH) by -49%. Cisplatin decreased catalase, superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymes by -47%, -49% and -59%, respectively. ALA decreased the MDA by -286% and increased the GSH, catalase, SOD and GPx levels by +60%, +81%, +90% and +38%, respectively. ALA increased mRNA expression of catalase, CuZn SOD and GPx genes near to normalcy compared to cisplatin-treated mice. Cisplatin-treated mice increased caspase-3-activity by +223%, nitric oxide (NO) by +74% and inducible nitric oxide synthase (iNOS) by 10 fold. ALA intake declined these changes by -43%, -45% and -73%, respectively. ALA may play renoprotective role on cisplatin-induced nephrotoxicity through antioxidant and antiapoptotic mechanisms combined with initiation of mRNA expression of antioxidant genes.

Cancer therapy and vaccination.

Cancer remains one of the leading causes of death worldwide, both in developed and in developing nations. It may affect people at all ages, even fetuses, but the risk for most varieties increases with age. Current therapeutic approaches which include surgery, chemotherapy and radiotherapy are associated with adverse side effects arising from lack of specificity for tumors. The goal of any therapeutic strategy is to impact on the target tumor cells with limited detrimental effect to normal cell function. Immunotherapy is cancer specific and can target the disease with minimal impact on normal tissues. Cancer vaccines are capable of generating an active tumor-specific immune response and serve as an ideal treatment due to their specificity for tumor cells and long lasting immunological memory that may safeguard against recurrences. Cancer vaccines are designed to either prevent (prophylactic) or treat established cancer (therapeutic). Identification of tumor-associated antigens (TAAs) and tumor-specific antigens (TSAs) has led to increased efforts to develop vaccination strategies. Vaccines may be composed of whole cells or cell extracts, genetically modified tumor cells to express costimulatory molecules, dendritic cells (DCs) loaded with TAAs, immunization with soluble proteins or synthetic peptides, recombinant viruses or bacteria encoding tumor-associated antigens, and plasmid DNA encoding TSAs or TAAs in conjunction with appropriate immunomodulators. All of these antitumor vaccination approaches aim to induce specific immunological responses and localized to TAAs, destroying tumor cells alone and leaving the vast majority of other healthy cells of the body untouched.

Crocin “saffron” protects against beryllium chloride toxicity in rats through diminution of oxidative stress and enhancing gene expression of antioxidant enzymes

Beryllium chloride (BeCl(2)) is a highly toxic substance that accumulates in different tissues after absorption. The purpose of this study was to investigate protective role of crocin against BeCl(2)-intoxication in rats. Male Wistar rats were used in this study and categorised into four groups (n=8). Group I served as normal control rats. Group II treated orally with BeCl(2) 86 mg/kg b.w. for five consecutive days. This dose was equivalent to experimental LD(50). Group III treated intraperitoneally with crocin 200 mg/kg b.w. for seven consecutive days. Group IV received crocin for seven consecutive days before BeCl(2) administration. Blood samples and liver and brain homogenates were obtained for haematological, biochemical and RT-PCR examinations. The haematocrit value, RBCs count and haemoglobin concentration were significantly decreased in BeCl(2)-treated rats. A significant increase was observed in rat liver and brain malondialdehyde level and protein carbonyls content in BeCl(2) exposed group compared to the control group, and these values were significantly declined upon administration of crocin. Lactate dehydrogenase levels in rat liver and brain significantly increased compared to the control group and was associated with significant decrease in catalase and superoxide dismutase activities. Reduced glutathione hepatic contents of BeCl(2)-treated rats were significantly decreased. There was significant decline in mRNA expression of catalase and superoxide dismutase genes in BeCl(2)-intoxicated rats compared to the normal rats. Crocin treatment prior to BeCl(2) intake resulted in significant increase in mRNA expressions of catalase and superoxide dismutase genes near to normalcy. The haematological and biochemical parameters were restored near to normal levels. Our results suggested that, BeCl(2) induced oxidation of cellular lipids and proteins and that administration of crocin reduced BeCl(2)-induced oxidative stress combined with initiation of mRNA expression of antioxidant genes.

Aroclor 1254 induced cytotoxicity and mitochondrial dysfunction in isolated rat hepatocytes.

Polychlorinated biphenyls (PCBs) are widespread persistent environmental contaminants that display a complex spectrum of toxicological properties, including hepatotoxicity. Although Aroclor 1254 is ubiquitous in the environment, its potential cytotoxic effect on rat hepatocytes and the mechanism underlines its cytotoxicity are not fully investigated. Therefore, the present study was conducted to investigate: (1) the potential cytotoxicity of Aroclor 1254 in rat hepatocytes, and (2) characterization of the molecular mechanisms involved in the Aroclor 1254-induced hepatotoxicity, particularly the role of mitochondria, possibly a primary target in such event, could greatly explain the cytotoxic effect of Aroclor 1254 in rat hepatocytes. Hepatocytes were isolated from adult male albino rats and incubated for 24h in a fresh media containing 0, 20, 30, 40, 50 or 60muM of Aroclor 1254. At the end of incubation, hepatocytes and hepatocyte mitochondria were used for the assay. Our results showed cytotoxicity of Aroclor 1254 in rat hepatocytes starting at a concentration of 30muM as manifested by increased lactate dehydrogenase (LDH) leakage, decreased cell viability (MTT assay) and increased lipid peroxidation. As mitochondria are known to be one possible site of the cell damage, the effects of Aroclor 1254 on hepatocyte mitochondria was investigated. Aroclor 1254 induced reactive oxygen species (ROS) generation in hepatocyte mitochondria, inhibited mitochondrial respiratory chain complexes I and III and beta-oxidation of free fatty acids, depletion of mitochondrial antioxidant enzymes GPx and GR and the non-enzymatic antioxidant reduced glutathione, inhibited mitochondrial membrane potential (Deltapsi(m)), decreased mitochondrial aconitase and cardiolipin content, and elevated levels of cytochrome P450 subfamily, CYP1A and CYP2B activities as indicated by ethoxyresorufin O-deethylase (EROD) and pentoxyresorufin O-deethylase (PROD). Therefore, we can conclude that Aroclor 1254 induced rat hepatocyte toxicity and our findings provide evidence to propose that mitochondria are one of the most important and earliest cell targets in Aroclor 1254-mediated toxicity and delineate several mitochondrial processes at least, in part, by induction of oxidative stress. These findings can be useful in future cytoprotective therapy approaches. Since mitochondrial events appear to be targeted in hepatocellular damage induced by Aroclor 1254, an antioxidant therapy targeted to mitochondria may constitute an interesting strategy to ameliorate its toxicity.

Dibutyl phthalate induces oxidative stress and impairs spermatogenesis in adult rats

Phthalates are abundantly produced plasticizers, and dibutyl phthalate (DBP) is the most widely used derivative in various consumer products and medical devices. This study was conducted to further explore the potential testicular toxicity of DBP in adult rats and to elucidate the underlying mechanisms. Adult male albino rats were treated orally with DBP at doses of 0, 200, 400, or 600 mg/kg/day for 15 consecutive days. Testicular weight, sperm count, and motility were significantly decreased. Treatment with DBP decreased serum follicle-stimulating hormone and testosterone levels and testicular lactate dehydrogenase activity. DBP treatment also decreased serum total antioxidant capacity and the activities of the testicular antioxidant enzymes, such as superoxide dismutase, catalase, and glutathione reductase. Further, DBP treatment provoked degeneration with absence of spermatogenesis and sperms and necrosis in some of seminiferous tubules. These results indicated that oxidative stress and subsequent decrease in testosterone secretion were the potential underlying mechanism of DBP-induced testicular toxicity.

Lipoic acid mitigates bisphenol A-induced testicular mitochondrial toxicity in rats

Bisphenol A (BPA) is one of the highest volume chemicals produced worldwide. BPA is used in the production of polycarbonate plastics and epoxy resins used in manufacturing plastic baby bottles and lining of food cans. In this study, we investigated the BPA-induced testicular oxidative stress and perturbation of mitochondrial marker enzymes in male albino rats and its amelioration by α-lipoic acid (LA). Rats were administered a dose of BPA (10 mg/kg body weight) orally for 14 days. This resulted in decreased testes weight, total testicular protein content, testicular enzymes such as acid phosphatase, alkaline phosphatase and lactate dehydrogenase and decline in activities of marker mitochondrial enzymes such as succinate dehydrogenase, malate dehydrogenase, isocitrate dehydrogenase, monoamine oxidase and NADH dehydrogenase. The serum testosterone and total antioxidant status were reduced. Besides, it also affected the activities of testicular antioxidant enzymes such as glutathione reductase, glutathione peroxidase, superoxide dismutase and catalase. BPA also caused lipid peroxidation and decrease in reduced glutathione content of mitochondria. The co-administration of LA (20 mg/kg body weight; orally for 14 days) together with BPA resulted in restoration of the mitochondrial marker enzyme activities and increasing enzymatic and non-enzymatic antioxidants of mitochondria. The obtained results demonstrated that LA has a potential role in mitigating BPA-induced mitochondrial toxicity through antioxidant mechanism or by direct free radical scavenging activity.