Lead induced alterations in nitrite and nitrate levels in different regions of the rat brain

Pergularia tomentosa coupled with selenium nanoparticles salvaged lead acetate-induced redox imbalance, inflammation, apoptosis, and disruption of neurotransmission in rats’ brain

In this study, the neuroprotective potential of either Pergularia tomentosa leaf methanolic extract (PtE) alone or in combination with selenium nanoparticles (SeNPs-PtE) was investigated against lead acetate (PbAc)-induced neurotoxicity. Experimental rats were pretreated with PtE (100 mg/kg) or SeNPs-PtE (0.5 mg/kg) and injected intraperitoneally with PbAc (20 mg/kg) for 2 weeks. Notably, SeNPs-PtE decreased brain Pb accumulation and enhanced the level of dopamine and the activity of AChE compared to the control rats. In addition, elevated neural levels of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione along with decreased lipid peroxidation levels were noticed in pretreated groups with SeNPs-PtE. Moreover, SeNPs-PtE significantly suppressed neural inflammation, as indicated by lower levels of interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha, nuclear factor-kappa B p65, and nitric oxide in the examined brain tissue. The molecular results also unveiled significant down-regulation in iNOS gene expression in the brains of SeNPs-PtE-treated rats. In addition, SeNPs-PtE administration counteracted the neural loss by increasing B-cell lymphoma 2 (Bcl-2) and brain-derived neurotrophic factor levels as well as decreasing BCL2-associated X protein and caspase-3 levels. To sum up, our data suggest that P. tomentosa extract alone or in combination with SeNPs has great potential in reversing the neural tissue impairment induced by PbAc via its antioxidant, anti-inflammatory, and anti-apoptotic activities. This study might have therapeutic implications in preventing and treating several lead-induced neurological disorders.

Neurological effects of subchronic exposure to dioctyl phthalate (DOP), lead, and arsenic, individual and mixtures, in immature mice

Dioctyl phthalate (DOP) (200, 500, and 1000 mg kg^-1 bw, i.g.), Pb (Ac)₂ (50 mg L^-1, p.o.), and NaAsO₂ (10 mg L^-1, p.o.) were administered individually and as mixtures to weanling male mice for 8 weeks. It was observed that Pb, As, and DOP exposure could significantly inhibit the growth and development of mice. Compared with the Pb, As, and Pb + As groups, the activities of iNOS and TNOS were significantly increased, the levels of AChE and SOD were significantly decreased, and the level of MDA was significantly increased in the Pb + DOP-H, As + DOP-H, and Pb + As + DOP-H groups. The factorial analysis shows that the iNOS, TNOS, and AChE present synergistic effects on Pb, As, and DOP. A significant increase of escape latency and a significant decrease of original platform quadrant stops were observed between Pb + As + DOP-H and Pb + As groups. The factorial analysis shows that there was a synergistic effect on Pb, As, and DOP. Compared with that of the control group, the expression levels of caspase-3 and Bax expression in Pb + As, DOP-H, Pb + DOP-H, As + DOP-H, and Pb + As + DOP-H groups were significantly increased in the hippocampus. The expression levels of Bcl-2 expression decreased significantly and the Bax/Bcl-2 ratio increased significantly. Pathological alterations on the hippocampus were found in exposed groups. This result shows that combined exposure of Pb, As, and DOP could induce neurotoxicity, of which possible mechanism is hippocampal neuronal apoptosis. Graphical abstract This study shows that there were three components with eigenvalues greater than 1, which together explained 89.40% of total variance. The first component (PC1) showed high loadings on B-SOD, L-SOD, B-MDA, L-MDA, K-MDA, iNOS, tNOS, and AChE and accounted for 46.55% of the total variance after Varimax rotation. PC2 accounted for 23.81% of the total variance with high loadings on B-As, L-As, K-As, and K-SOD, whereas PC3 showed high loadings on B-Pb, L-Pb, and K-Pb and accounted for 19.04% of the total variance.

Neurological Toxicity of Individual and Mixtures of Low Dose Arsenic, Mono and Di (n-butyl) Phthalates on Sub-Chronic Exposure to Mice

The objective of this study was to evaluate the toxicity of individual and mixtures of di(n-butyl) phthalates (DBP) and their active metabolite monobutyl phthalate (MBP) and arsenic (As) on spatial cognition associated with hippocampal apoptosis in mice. Mice were exposed, individually or in combination, to DBP (50 mg/kg body weight, intragastrically), MBP (50 mg/kg body weight, intragastrically), and As (10 mg/L, per os) for 8 weeks. The Morris water maze test showed that mice exposed to DBP/MBP combined with As exhibited longer escape latencies and the lower average number of crossing the platform. The As content in the hippocampus after As exposure increased as compared to those without As exposure. In mice exposed to DBP/MBP combined with As, pathological alterations and oxidative damage to the hippocampus were found. Expression of apoptosis-related protein: Bax and caspase-3 were significantly increased in the hippocampus, while there was no significant change in expression of Bcl-2. The results suggested that DBP and MBP combined with As can induce spatial cognitive deficits through altering the expression of apoptosis-related protein and As played a critical role in cognition impairments. And the joint exposure has antagonistic effect.

Effects of xenobiotics on total antioxidant capacity

The objective of this article was to review the effects of xenobiotics on total antioxidant capacity (TAC). Measurement of TAC is appropriate for evaluation of the total antioxidant defenses of blood, cells, and different kinds of tissues and organs. TAC is reduced by alcoholism, smoking, and exposure to radiation, herbicides, carbon monoxide, carbon tetrachloride, lead, arsenic, mercury, cadmium, aluminum, and other toxic elements. The test is also an important tool in evaluating environmental and occupational exposure.

PKC isoforms were reduced by lead in the developing rat brain

A plethora of protein kinase C (PKC) isoforms play important roles in regulating synaptic plasticity and neurotransmitter release. Even though, most PKC isoforms are involved in Pb-induced neuronal toxicity, its mechanism is still unclear. The current study addresses the effect of Pb on PKC isoforms in different regions of the developing rat brain. Sprague-Dawley (SD) pregnant rats were exposed to 0.1% Pb as lead acetate dissolved in distilled deionized water (DDW) from gestation day 6 through 21 postnatal day (PND). Control rats were allowed to drink DDW. Pups were sacrificed on PND 1, 5, 10 and 45. Rat brain was immediately excised and separated into the brain stem (BS), the cerebellum (CB), the hippocampus (HC) and the frontal cortex (FC). The Pb level in different regions of the brain was determined using an analytical graphite tube atomizer (Varian). Typical PKC (alpha, beta, gamma), novel PKC (epsilon) and atypical PKC (mu) in the above brain regions were enriched by immunoprecipitation and later were assayed by Western blotting. The total, calcium-dependent and -independent PKC activities were determined by the radioactivity of total gamma-32P transferred to histone. The results indicated that on PND 1, Pb reduced the PKC-gamma protein in HC and FC, whereas on PND 5 the proteins of PKC isoforms (alpha, beta, gamma, epsilon, mu) in HC and FC were significantly reduced. These reductions in PKC proteins were higher in membrane fractions than in cytosolic fractions. On PND 10, Pb reduced all PKC isoforms. However, on PND 45, Pb had no significant effect on all PKC isoforms except epsilon. Pb inhibited the total PKC activity by 70% on PND 1 and 5, the bulk of these PKC activities were calcium-dependent. The results suggest that during early stages of the rat brain development, Pb exposure decreased PKC activities and also reduced PKC isoforms including PKC-gamma and epsilon which are reported to have roles in the memory formation and long-term potentiation (LTP).