Prenatal and Lactational Lead Exposure Enhanced Oxidative Stress and Altered Apoptosis Status in Offspring Rats’ Hippocampus

Oxidative stress and apoptosis facilitation in the developing central nervous system (CNS) have been inferred as two mechanisms related to lead’s neurotoxicity, and excessive reactive oxygen species (ROS) can promote oxidative stress and apoptosis facilitation. Few studies systematically investigated the potential relationship among oxidative stress, ROS generation, and apoptosis facilitation after lead exposure in earlier life as a whole. To better understand the adverse effect on the developing central nervous system (CNS) after lead exposure during pregnancy and lactation, the indexes of oxidative stress, apoptosis status, and Bax and Bcl-2 expression of offspring rats’ hippocampus were determined. Pregnant rats were randomly divided into four groups and given free access to drinking water which contained 0 %, 0.05 %, 0.1 %, and 0.2 % Pb(AC)₂ respectively from gestation day 0 to postnatal day 21 (PND21). Results showed that ROS and malondialdehyde level of either PND7 or PND21 pups’ hippocampus were significantly raised; reduced glutathione level and superoxide dismutase activity were obviously decreased following the increase of blood and brain lead level. Similar to apoptotic indexes, Bax/Bcl-2 ratio increased after 0.1 % and 0.2 % Pb(AC)₂ exposure, especially for the pups on PND7. Comparing with cortex, the hippocampus seemed much more sensitive to damage induced by lead. We concluded that the disruption of pro-oxidant and antioxidant balance and apoptosis facilitation could be associated with the mechanisms of neurotoxicity after lead exposure in earlier life.     

The Role of Klotho Protein Against Sevoflurane-Induced Neuronal Injury

The effects of general anesthetics on the developing brain have aroused much attention in recent years. Sevoflurane, a commonly used inhalation anesthetic especially in pediatric anesthesia, can induce developmental neurotoxicity. In this study, the differentially expressed mRNAs in the hippocampus of newborn rats exposed to 3% sevoflurane for 6 h were detected by RNA-Sequencing. Those data indicated that the mRNA of Klotho was increased after exposure to sevoflurane. Moreover, the protein expression of Klotho was assayed by Western Blot. Besides over-expression and under-expression of Klotho protein, we also detected changes of cell proliferation, ROS, JC-1, and Bcl-2/Bax ratio in PC12 cells exposed to sevoflurane. After exposure to 3% sevoflurane, the expression of Klotho protein increased in the hippocampus of neonatal rats. In PC12 cells, exposure to sevoflurane could increase cellular ROS level, reduce mitochondrial membrane potential and Bcl-2/Bax ratio. While overexpression of Klotho alleviated the above changes, knockdown of Klotho aggravated the injury of sevoflurane. Klotho protein could reduce oxidative stress and mitochondrial injury induced by sevoflurane in the neuron.

     

Neuroprotective Effect of Crocin on Acrylamide-induced Cytotoxicity in PC12 cells

Acrylamide (ACR) is a potent neurotoxic in human and animal models. In this study, the effect of crocin, main constituent of Crocus sativus L. (Saffron) on ACR-induced cytotoxicity was evaluated using PC12 cells as a suitable in vitro model. The exposure of PC12 cells to ACR reduced cell viability, increased DNA fragmented cells and phosphatidylserine exposure, and elevated Bax/Bcl-2 ratio. Results showed that ACR increased intracellular reactive oxygen species (ROS) in cells and ROS played an important role in ACR cytotoxicity. The pretreatment of cells with 10–50 μM crocin before ACR treatment significantly attenuated ACR cytotoxicity in a dose-dependent manner. Crocin inhibited the downregulation of Bcl-2 and the upregulation of Bax and decreased apoptosis in treated cells. Also, crocin inhibited ROS generation in cells exposed to ACR. In conclusion, our results indicated that pretreatment with crocin protected cells from ACR-induced apoptosis partly by inhibition of intracellular ROS production.     

Hydrogen Sulfide Attenuates Neuronal Injury Induced by Vascular Dementia Via Inhibiting Apoptosis in Rats

Hydrogen sulfide (H₂S) is a gaseous messenger and serves as an important neuromodulator in the central nervous system. The current study was undertaken to investigate whether H₂S attenuates the neuronal injury induced by vascular dementia (VD). Rats were subjected to bilateral common carotid artery and vertebral artery occlusion for 5 min three times in an interval of 5 min to induce VD. An H₂S donor, sodium hydrosulfide (NaHS) or an inhibitor of cystathionine-β-synthase, hydroxylamine (HA) was administered intraperitoneally. The number of neurons in the hippocampus was determined by hematoxylin and eosin staining, and the performance of learning and memory was tested by the Morris water maze. H₂S content in plasma was evaluated. Apoptosis in the hippocampus was assessed by flow cytometry. In addition, Bcl-2 and Bax expression was analyzed by immunohistochemical staining. The neuronal injury occurred gradually with a decreased number of neurons and increased apoptosis ratio in the hippocampus over 720 h after VD. The H₂S level was also gradually decreased in plasma over 720 h after VD, which negatively correlated with the apoptosis ratio in the hippocampus after VD. In addition, NaHS treatment significantly attenuated neuronal injury and improved neural functional performance, whereas HA exaggerated the neuronal injury and exacerbated learning and memory at 720 h after VD. Furthermore, NaHS treatment markedly improved the ratio of Bcl-2 over Bax with increased Bcl-2 expression and decreased Bax expression. In contrast, HA reduced the ratio of Bcl-2 over Bax. It is suggested that H₂S attenuates VD injury via inhibiting apoptosis and may have potential therapeutic value for VD.     

The timing of re-institution of good blood glucose control affects apoptosis and expression of Bax and Bcl-2 in the retina of diabetic rats

Hyperglycemia initiates a sequence of events that leads to the development of diabetic retinopathy. We explored the effect of re-institution of good blood glucose control on apoptosis and apoptosis related genes (Bax and Bcl-2) in the retina of diabetic rats. Fifty male Wistar rats randomly divided into five groups : normal control group (CON), diabetic rats with high blood glucose levels for 8 months group (DM) ,diabetic rats with good blood glucose control for 8 months group (DM₁),diabetic rats with poor blood glucose control for 2 month followed by good blood glucose control for six additional months group (DM₂), rats with poor blood glucose control for 4 months followed by good blood glucose levels for four additional months group (DM₃). Expression of Bax and Bcl-2 in the retina was studied by immunohistochemistry and the apoptotic cells were stained using the TUNEL method. The apoptotic cell, expression of Bax and Bcl-2 and the ratio of Bax to Bcl-2 in the retina was increased in DM group compared with normal rats’ (P < 0.01). There was no significant difference in apoptotic cells and the ratio of Bax to Bcl-2 between DM₁ group and CON group. The number of TUNEL positive cells and Bax to Bcl-2 ratio was partially reversed in DM₂ group. But glucose control had no effect on the apoptotic cells and the expression of Bax and Bcl-2 in DM₃ group. There was a positive correlation between apoptotic cells and Bax/Bcl-2 ratio in the retina (r = 0.808, P < 0.01). Good blood glucose control at early stage can decrease the number of apoptotic cells in the retina; the decreased apoptosis is correlated with the down-regulation of Bax to Bcl-2 ratio.     

Dietary intervention of cow ghee and soybean oil on expression of cell cycle and apoptosis related genes in normal and carcinogen treated rat mammary gland

The present study investigated the effect of cow ghee (clarified butter fat) versus soybean oil on the expression of cyclins A and D1, and apoptosis regulating Bax, Bcl-2 and PKC-α genes in mammary gland of normal and 7,12-dimethylbenz(a)anthracene (DMBA) treated rats. Two groups of 21 days old female rats were fed for 44 weeks diet containing cow ghee or soybean oil (10%). The animals were given DMBA (30 mg/kg body weight) through oral intubation after 5 weeks feeding. Another two groups fed similarly but not given DMBA served as respective controls. In control groups, the expression of cyclin A was similar on both cow ghee and soybean oil, but that of cyclin D1 was more on soybean oil diet. However, in DMBA treated groups, the expression levels of cyclins A and D1 were significantly greater on soybean oil than on cow ghee. The expression levels of Bax, Bcl-2 and PKC-α were similar in two control groups. However, in tumor tissue expression levels of Bcl-2 and PKC-α were significantly lower in cow ghee fed rats than in soybean oil fed ones, but Bax was similarly expressed in both DMBA treated groups. The pro-apoptotic ratio Bax/Bcl-2 increased and the anti-apoptotic ratio PKC-α*(Bcl-2/Bax) decreased in cow ghee group compared to soybean oil group in DMBA treated rats. Hence, the decreased expressions of cyclins A and D1, Bcl-2 and PKC-α mediate the mechanism by which cow ghee protects from mammary carcinogenesis.     

硒对铅暴露致神经损伤的拮抗作用研究

目的:研究铅暴露诱导的神经毒性损伤作用,明确铅暴露引发神经毒性损伤的部分机制以及硒的保护作用。方法:通过哺乳期染铅及补充硒建立铅暴露动物模型;通过TUNEL实验确定铅暴露引发的神经损伤;通过Western blot实验检测Bax、Bcl-2、Caspase-3水平确定铅暴露对凋亡途径的启动;并确证补硒在铅神经毒性作用下对机体的保护作用。结果:1.哺乳期铅暴露能够引起仔鼠海马神经细胞凋亡的发生;2.铅暴露能够诱导Bax/Bcl-2水平改变,激活Caspase-3。3.同时给予硒干预后,机体抗铅神经毒性能力显著增加。结论:1.铅暴露能够诱导海马部位神经毒性损伤,损伤可能通过启动凋亡途径而发生,2.补硒能够通过拮抗凋亡发生从而拮抗铅的神经毒性,产生保护作用。     

Neuroprotective effect of rutin against colistin-induced oxidative stress,inflammation and apoptosis in rat brain associated with the CREB/BDNF expressions

The purpose of the current study was to examine the neuroprotective effect of rutin against colistin-induced neurotoxicity in rats. Thirty-five male Sprague Dawley rats were randomly divided into 5 groups. The control group (orally received physiological saline), the rutin group (orally administered 100 mg/kg body weight), the colistin group (i.p. administered 15 mg/kg body weight), the Col?+?Rut 50 group (i.p. administered 15 mg/kg body weight of colistin, and orally received 50 mg/kg body weight of rutin), the Col?+?Rut 100 group (i.p. administered 15 mg/kg body weight of colistin, and orally received 100 mg/kg body weight of rutin). Administration of colistin increased levels of glial fibrillary acidic protein and brain-derived neurotrophic factor and acetylcholinesterase and butyrylcholinesterase activities while decreasing level of cyclic AMP response element binding protein and extracellular signal regulated kinases 1 and 2 (ERK1/2) expressions. Colistin increased oxidative impairments as evidenced by a decrease in level of nuclear factor erythroid 2-related factor 2 (Nrf-2), glutathione, superoxide dismutase, glutathione peroxidase and catalase activities, and increased malondialdehyde content. Colistin also increased the levels of the apoptotic and inflammatoric parameters such as cysteine aspartate specific protease-3 (caspase-3), p53, B-cell lymphoma-2 (Bcl-2), nuclear factor kappa B (NF-κB), Bcl-2 associated X protein (Bax), tumor necrosis factor-α (TNF-α) and neuronal nitric oxide synthase (nNOS). Rutin treatment restored the brain function by attenuating colistin-induced oxidative stress, apoptosis, inflammation, histopathological and immunohistochemical alteration suggesting that rutin supplementation mitigated colistin-induced neurotoxicity in male rats.

     

Protective Role of Quercetin on PCBs-Induced Oxidative Stress and Apoptosis in Hippocampus of Adult Rats

Polychlorinated biphenyls (PCBs) exposure produces neurodegeneration and induces oxidative stress. Neuroprotective role of quercetin, on PCBs induced apoptosis in hippocampus has not yet been studied. The present study is focused to see whether quercetin supplementation precludes against PCBs induced oxidative stress and hippocampal apoptosis. The results have shown that quercetin at 50 mg/kg bwt/30 days has protected oxidative stress in hippocampus of adult male rats. Quercetin, a free radical scavenger decreased the levels of oxidative stress markers in the hippocampus of simultaneous PCB+quercetin treated rats. The pro-apoptotic and anti-apoptotic molecules such as Bad, Bid, Bax and Bcl2 were altered in the hippocampus of experimental animals. PCBs increased the DNA damage and induced neurodegeneration were assessed by histological studies. PCB induced ROS may be linked to increased hippocampal neuronal apoptosis. Quercetin supplementation decreased the neuronal damage and scavenged the free radicals induced by PCBs and protects PCBs induced apoptosis and oxidative stress.     

Activation of Akt/GSK-3β signaling pathway is involved in intermedin1–53 protection against myocardial apoptosis induced by ischemia/reperfusion

Intermedin (IMD) is a novel member of the calcitonin/calcitonin gene-related peptide family. We investigated the cardioprotective mechanism of IMD_1–53 in the in vivo rat model of myocardial ischemia/reperfusion (I/R) injury and in vitro primary neonatal cardiomyocyte model of hypoxia/reoxygenation (H/R). Myocardial infarct size was measured by 2,3,5-triphenyl tetrazolium chloride staining. Cardiomyocyte viability was determined by trypan blue staining, cell injury by lactate dehydrogenase (LDH) leakage, and cardiomyocyte apoptosis by terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling assay, Hoechst staining, gel electrophoresis and caspase 3 activity. The translocation of mitochondrial cytochrome c of myocardia and expression of apoptosis-related factors Bcl-2 and Bax, phosphorylated Akt and phosphorylated GSK-3β were determined by western blot analysis. IMD_1–53 (20 nmol/kg) limited the myocardial infarct size in rats with I/R; the infarct size was decreased by 54%, the apoptotic index by 30%, and caspase 3 activity by 32%; and the translocation of cytochrome c from mitochondria to cytosol was attenuated. IMD_1–53 increased the mRNA and protein expression of Bcl-2 and ratio of Bcl-2 to Bax by 81 and 261%, respectively. IMD_1–53 (1 × 10⁻⁷ mol/L) inhibited the H/R effect in cardiomyocytes by reducing cell death by 43% and LDH leakage by 16%; diminishing cellular apoptosis; decreasing caspase 3 activity by 50%; and increasing the phosphorylated Akt and GSK-3β by 41 and 90%, respectively. The cytoprotection of IMD_1–53 was abolished with LY294002, a PI3K inhibitor. In conclusion, IMD_1–53 exerts cardioprotective effect against myocardial I/R injury through the activation of the Akt/GSK-3β signaling pathway to inhibit mitochondria-mediated myocardial apoptosis.     

Lead Affects Apoptosis and Related Gene <Emphasis Type="Italic">XIAP</Emphasis> and <Emphasis Type="Italic">Smac</Emphasis> Expression in the Hippocampus of Developing Rats

Lead (Pb) exposure poses devastating effects on central nervous system development of children. To replicate aspects of this neurotoxicity, we examined the effect of lead on the expression of apoptosis and of apoptosis-related genes, XIAP (X chromosome-linked inhibitor of apoptosis protein) and Smac (second mitochondrial activator of caspase), in the hippocampus of developing rats. A total of 48 rats (30-day old) were randomly divided into four groups for intragastrical perfusion of lead acetate [Pb(Ac)₂]: untreated, low (2 mg/kg/d), medium (20 mg/kg/d), and high (200 mg/kg/d) dose groups. Pb content was determined in blood, and the apoptosis indexes and XIAP and Smac gene expression were analyzed in the hippocampus. There was a significant difference in apoptosis indexes (AI) between the exposed and control groups (p < 0.01). AI was highest in the high exposure group. XIAP gene expression was reduced in the exposed groups and the expression was negatively correlated with blood lead levels (BLLs) (p < 0.05). But the four groups did not differ in the expression of Smac (p > 0.05). Our data indicate that exposure to Pb(Ac)₂ caused a dose-dependent and significant increase of apoptosis in the hippocampus of developing rats through depressing the expression of the XIAP but not the Smac genes.     

Kinetics of Apoptosis and Expression of Apoptosis-Related Proteins in Rat CA3 Hippocampus Cells After Experimental Diffuse Brain Injury

The present study examined kinetics of apoptosis and expression of apoptosis-related proteins Bcl-2, Bax, and caspase-3 in the CA3 hippocampus cells after diffuse brain injury (DBI) induced experimentally in rats. Percentage of apoptotic cells and expressions of above proteins were examined by flow cytometry and immunohistochemistry. Substantial neuronal apoptosis was documented in the CA3 hippocampus cells after DBI (22.26 ± 2.97 % at 72 h after DBI vs. 2.92 ± 0.88 % in sham-operated animals). Expression of Bc1-2 decreased, while expression of Bax and caspase-3 increased after DBI, with caspase-3 expression peaking after that of Bax (72 vs. 48 h, respectively). Further, the Bc1-2/Bax expression ratio decreased prior to increase of caspase-3 expression. In conclusion, cell apoptosis and altered expressions of Bcl-2, Bax, and caspase-3 are present in the CA3 region of hippocampus after experimental DBI. Changes in the Bc1-2/Bax expression ratio may facilitate activation of caspase-3 and aggravate neuronal apoptosis after brain injury.     

The role of Nrf2/HO-1 signal pathway in regulating aluminum-induced apoptosis of PC12 cells

BackgroundAluminum has definite neurotoxicity and can lead to apoptosis of nerve cells, but the specific mechanism remains to be further explored. The aim of this study was to investigate the role of Nrf2/HO-1 signaling pathway in neural cell apoptosis induced by aluminum exposure.MethodsIn this study, PC12 cells were used as the research object, aluminum maltol [Al(mal)₃] was used as the exposure agent, and tert-butyl hydroquinone (TBHQ), an agonist of Nrf2, was used as the intervention agent to construct an in vitro cell model. Cell viability was detected by CCK-8 method, cell morphology was observed by light microscope, cell apoptosis was measured by flow cytometry, and expression of Bax and Bcl-2 proteins and Nrf2/HO-1 signaling pathway proteins were investigated by western blotting.ResultsWith the increase of Al(mal)₃ concentration, PC12 cell viability decreased, the early apoptosis rate and total apoptosis rate increased, the ratio of Bcl-2 and Bax protein expression decreased, and Nrf2/HO-1 pathway protein expression decreased. The use of TBHQ could activate the Nrf2/HO-1 pathway and reverse the apoptosis of PC12 cells induced by aluminum exposure.ConclusionNrf2/HO-1 signaling pathway plays a neuroprotective role in the apoptosis of PC12 cells caused by Al(mal)₃, which provides a possible target for the intervention of aluminum induced neurotoxicity.     

Protection of PMS777, a New AChE Inhibitor with PAF Antagonism, Against Amyloid-β-Induced Neuronal Apoptosis and Neuroinflammation

Amyloid-β (Aβ) plays a central role in the neuroinflammation and cholinergic neuronal apoptosis in Alzheimer’s disease, and thus has been considered as a main determinant of this disease. In the previous study, we reported that PMS777, a novel bis-interacting ligand for acetylcholinesterase (AChE) inhibition and platelet-activating factor (PAF) receptor antagonism, could significantly attenuate PAF-induced neurotoxicity. Continuing our efforts, we further investigated the protective effect of PMS777 on Aβ-induced neuronal apoptosis in vitro and neuroinflammation in vivo. PMS777 (1–100 μM) was found to inhibit Aβ-induced human neuroblastoma SH-SY5Y cell apoptosis in a concentration-dependent manner. Concurrently, PMS777 increased ratio of bcl-2 to bax mRNA, and inhibited both mRNA expression and activity of caspase-3 in SH-SY5Y cells after the exposure with Aβ. In vivo experimental study demonstrated that PMS777 could attenuate Aβ-induced microglial and astrocytic activation in the rat hippocampus after systemic administration. These results suggest that PMS777 potently protects against Aβ-induced neuronal apoptosis and neuroinflammation, and warrants further investigations in connection with its potential value in the treatment of Alzheimer’s disease. The authors Juan Li and Jinjia Hu contributed equally to this article.     

Hyperbaric oxygen induces apoptosis via a mitochondrial mechanism

During therapeutic hyperbaric oxygenation lymphocytes are exposed to high partial pressures of oxygen. This study aimed to analyze the mechanism of apoptosis induction by hyperbaric oxygen. For intervals of 0.5–4 h Jurkat-T-cells were exposed to ambient air or oxygen atmospheres at 1–3 absolute atmospheres. Apoptosis was analyzed by phosphatidylserine externalization, caspase-3 activation and DNA-fragmentation using flow cytometry. Apoptosis was already induced after 30 min of hyperbaric oxygenation (HBO, P < 0.05). The death receptor Fas was downregulated. Inhibition of caspase-9 but not caspase-8 blocked apoptosis induction by HBO. Hyperbaric oxygen caused a loss of mitochondrial membrane potential and caspase-9 induction. The mitochondrial pro-survival protein Bcl-2 was upregulated, and antagonizing Bcl-2 function potentiated apoptosis induction by HBO. In conclusion, a single exposure to hyperbaric oxygenation induces lymphocyte apoptosis by a mitochondrial and not a Fas-related mechanism. Regulation of Fas and Bcl-2 may be regarded as protective measures of the cell in response to hyperbaric oxygen.     

Electro-acupuncture Reduces Neuronal Apoptosis Linked to Bax and Bcl-2 Expression in the Spinal Cords of Cats Subjected to Partial Dorsal Root Ganglionectomy

While electro-acupuncture (EA) has been well known to contribute towards neuroplasticity occurring in both the central and the peripheral nervous system after injury, the underlying mechanism remains largely unknown. This study evaluated the effects and the possible mechanism of EA on neuronal apoptosis in the spinal cords of cats subjected to the removal of L₁–L₅ and L₇–S₂ dorsal root ganglion, sparing the L₆ dorsal root ganglion. EA treatment decreased the number of TUNEL-positive apoptotic cells in lamina II of the L₃ and L₆ cord segments at 7 and 14 days post operation (dpo). This EA-mediated neuroprotection is associated with a decrease in the number of Bax immunoreactive neurons and an increase in the number of Bcl-2 immunoreactive neurons. Furthermore, Western blot and RT-PCR analysis revealed a significant downregulation of Bax protein and its mRNA, but an upregulation of Bcl-2 in the dorsal horn of L₃ and L₆ cords at both 7 and 14 dpo. The present findings suggest that EA could inhibit neuronal apoptosis in dorsal root deafferentated cat spinal cords, possibly by Bax downregulation and Bcl-2 upregulation. Wei Zhao and Qi Zhao contributed equally to this work.     

Cornel Iridoid Glycoside Inhibits Inflammation and Apoptosis in Brains of Rats with Focal Cerebral Ischemia

The capacity of cornel iridoid glycoside (CIG) to suppress the manifestations of ischemic stroke was investigated. CIG was administered to rats by the intragastric route once daily for 7 days. Focal cerebral ischemia was induced by 2 h of middle cerebral artery occlusion followed by 24 h of reperfusion. In non-treated rats large infarct areas were observed within 24 h of reperfusion. Examination of the ischemic cerebral cortex revealed microglia and astrocyte activation, increased interleukin-1β (IL-1 β) and tumor necrosis factor-α (TNF-α) concentrations, increased DNA fragmentation in the ischemia penumbra, elevated Bax expression, increased caspase-3 cleavage, and decreased Bcl-2 expression. Pretreatment with CIG decreased the infarct area, DNA fragmentation, IL-1β and TNF-α concentrations, microglia and astrocyte activation, Bax expression, and caspase-3 cleavage while increasing Bcl-2 expression. CIG exerts anti-neuroinflammatory and anti-apoptotic effects which should prove beneficial for prevention or treatment of stroke.     

Effect of transforming growth factor-alpha on enterocyte apoptosis is correlated with EGF receptor expression along the villus-crypt axis during methotrexate-induced intestinal mucositis in a rat

The purpose of the present study was to evaluate the effect of transforming-growth factor-alpha (TGF-α) on enterocyte apoptosis following methotrexate (MTX) induced intestinal mucositis in a rat and in Caco-2 cells. Non-pretreated and pretreated with MTX Caco-2 cells were incubated with increasing concentrations of TGF-α. Cell apoptosis was determined by FACS cytometry. Adult rats were divided into four groups: Control, Control-TGF-α, MTX, and MTX- TGF-α rats. Three days later rats were sacrificed. Enterocyte apoptosis were measured at sacrifice. RT-PCR and Western Blotting was used to determine the level of Bax and Bcl-2 mRNA and protein. Real time PCR was used to measure epidermal growth factor receptor (EGFr) expression along the villus-crypt axis. The in vitro experiment has shown that treatment with TGF-α of Caco-2 cells results in a significant inhibition of cell apoptosis in a dose-dependent manner. In vivo experiment, a decreased levels of apoptosis in MTX- TGF-α rats corresponded with the decrease in Bax and with the increase in Bcl-2 at both mRNA and protein levels. The inhibiting effect of TGF-α on enterocyte apoptosis was strongly correlated with EGFr expression along the villus-crypt axis. In conclusion, treatment with TGF-α inhibits enterocyte apoptosis following MTX- injury in the rat.     

Effects of heavy metal (Pb) on arbuscular mycorrhizal fungi in vitro

The responses of Ri-TDNA-transformed roots and arbuscular mycorrhizal fungi established on Ri-TDNA-transformed roots to lead-amended media was investigated in vitro. At exposure to increasing concentrations of lead (2–10 mg/l[ppm]), three Ri-TDNA-transformed root clones viz., Swa, Swb and Swc, exhibited profuse growth. At exposure to increasing concentrations of lead (0.1–5 ppm), the dual cultures of Ri-TDNA-transformed roots and arbuscular mycorrhizal fungi., Glomus lamellosum/Swa, Glomus intraradices/Swb and Glomus proliferum/Swc, exhibited tolerance to 5 ppm of lead. When subjected to one physiological stress, either exposure to Pb or inoculation with AM fungi, Ri-TDNA-transformed root clones exuded more phenols in the growth medium than retained in the roots. When subjected to dual physiological stress, mycorrhizal Ri-TDNA-transformed roots growing on Pb-enriched medium, the total phenol content increased in the roots and exudation into the medium decreased.     

Protective Effects of Selenium,Zinc, or Their Combination on Cadmium-Induced Oxidative Stress in Rat Kidney

The present study was conducted to investigate whether the combined treatment with Se and Zn offers more beneficial effects than that provided by either of them alone in reversing Cd-induced oxidative stress in the kidney of rat. For this purpose, 30 adult male Wistar albino rats, equally divided into control and four treated groups, received either 200 ppm Cd (as CdCl₂), 200 ppm Cd + 500 ppm Zn (as ZnCl₂), 200 ppm Cd + 0.1 ppm Se (as Na₂SeO₃), or 200 ppm Cd + 500 ppm Zn + 0.1 ppm Se in their drinking water for 35 days. The results showed that Cd treatment decreased significantly the catalase (CAT) and glutathione peroxidase (GSH-Px) activities, whereas the superoxide dismutase (SOD) activity and the renal levels of lipid peroxidation (as malondialdehyde, MDA) were increased compared to control rats. The treatment of Cd-exposed rats with Se alone had no significant effect on the Cd-induced increase in the MDA concentrations but increased significantly the CAT activities and reversed Cd-induced increase in SOD activity. It also partially prevented Cd-induced decrease in GSH-Px activity. The treatment of Cd-exposed animals with Zn alone increased significantly the CAT activity and partially protected against Cd-induced increase in the MDA concentrations, whereas it had no significant effect on the Cd-induced increase in SOD activity and decrease in GSH-Px activity. The combined treatment of Cd-exposed animals with Se and Zn was more effective than that with either of them alone in reversing Cd-induced decrease in CAT and GSH-Px activities and Cd-induced increase in MDA concentrations. Results demonstrated beneficial effects of combined Se and Zn treatment in Cd-induced oxidative stress in kidney and suggest that Se and Zn can have a synergistic role against Cd toxicity. I. Messaoudi and J. El Heni have equally contributed to this work.