Protective Effects of Green Tea Supplementation against Lead-Induced Neurotoxicity in Mice

Threshold and interaction effects of environmental variables affecting the spatial distribution of Pb

Understanding the spatial distribution of soil Pb and its potential influence mechanism is significant for controlling Pb pollution in tea plantations and guaranteeing food safety. The linear and nonlinear relationships between Pb and environmental variables have been widely studied, but the threshold and interaction effects of its environmental variables are often neglected. In this study, 81 tea plantation soils were collected and determined the thresholds and interaction effects of environmental variables on Pb through the GBDT model. The results revealed that the 10 selected environmental variables together explained 71.01 % of the variation in Pb content, with the top three factors being pH, total phosphorus (TP), and distance from roads (dis_road). Most environmental variable had threshold effects on Pb. By visualizing the interaction of pH, TP, and dis_road on Pb concentration, we show that both two-way and three-way interactions are able to further explain its variation. The interaction between TP and dis_road alone accounts for 5.70 %, between pH and dis_road alone accounts for 7.92 %, and between pH and TP alone accounts for 5.83 % of the variation in Pb concentration. However, the three-way interaction between pH, TP, and dis_road alone explains 11.85 % of the variation in Pb concentration. Understanding these interactions is important for gaining insight into the underlying processes leading to Pb pollution and promoting the tea industry's sustainable development in China and abroad.

5,7-dihydroxy-3',4',5'-trimethoxyflavone mitigates lead induced neurotoxicity in rats via its chelating, antioxidant, anti-inflammatory and monoaminergic properties

Chronic exposure to lead (Pb) induces neurodegenerative changes in animals and humans. Drugs with strong antioxidant properties are effective against Pb-mediated neurotoxicity. In a prior study, we identified 5,7-dihydroxy-3',4',5'-trimethoxyflavone (TMF) from Ocimum basilicum L. leaves as a potent antioxidant and neuroprotective compound. This research explores TMF's neuroprotective effects against Pb-induced brain toxicity in rats to establish it as a therapeutic agent. Rats received lead acetate (100 mg/kg, orally, once daily) for 30 days to induce brain injury, followed by TMF treatment (5 and 10 mg/kg, oral, once daily) 30 min later. Cognitive and motor functions were assessed using Morris Water Maze and horizontal bar tests. Lead, monoamine oxidase (MAO) A and B enzymes, reduced glutathione (GSH), thiobarbituric acid reactive species (TBARS), Tumor necrosis factor-alpha (TNF-α), and IL-6 levels were measured in the hippocampus and cerebellum. Pb exposure impaired cognitive and motor functions, increased Pb, TBARS, TNF-α, and IL-6 levels, and compromised MAO A & B and GSH levels. TMF reversed Pb-induced memory and motor deficits and normalized biochemical anomalies. TMF's neuroprotective effects against lead involve chelating, antioxidant, anti-inflammatory, and monoaminergic properties, suggesting its potential as a treatment for metal-induced brain injury.

Interaction of Heavy Metal Lead with Gut Microbiota: Implications for Autism Spectrum Disorder

Autism Spectrum Disorder (ASD), a neurodevelopmental disorder characterized by persistent deficits in social interaction and communication, manifests in early childhood and is followed by restricted and stereotyped behaviors, interests, or activities in adolescence and adulthood (DSM-V). Although genetics and environmental factors have been implicated, the exact causes of ASD have yet to be fully characterized. New evidence suggests that dysbiosis or perturbation in gut microbiota (GM) and exposure to lead (Pb) may play important roles in ASD etiology. Pb is a toxic heavy metal that has been linked to a wide range of negative health outcomes, including anemia, encephalopathy, gastroenteric diseases, and, more importantly, cognitive and behavioral problems inherent to ASD. Pb exposure can disrupt GM, which is essential for maintaining overall health. GM, consisting of trillions of microorganisms, has been shown to play a crucial role in the development of various physiological and psychological functions. GM interacts with the brain in a bidirectional manner referred to as the "Gut-Brain Axis (GBA)". In this review, following a general overview of ASD and GM, the interaction of Pb with GM in the context of ASD is emphasized. The potential exploitation of this interaction for therapeutic purposes is also touched upon.

Toxicity assessment of heavy metal (Pb) and its bioremediation by potential bacterial isolates

Lead (Pb) is a non-essential metal with high toxicity, is persistent, is not biodegradable, and has no known biological function. It is responsible for severe health and environmental issues that need appropriate remediation. Therefore, microbes have thrived in a lead-contaminated environment without exhibiting any negative impacts. The present study aimed to examine the toxic effects of lead on animals and the isolation, identification, and characterization of lead-resistant bacterial strains and their biodegradation potential. After oral administration of lead for 4 weeks, mice showed an elevated level of leukocytes and a decrease in TEC, Hb, PCV, MCV, MCH, and MCHC levels. However, a decline in body weight and inflammation and oxidative stress was observed in liver tissues. To remediate toxic heavy metal, lead-resistant bacterial strains were isolated, among which Enterobacter exhibited maximum degradation potential at high lead concentrations. It was identified by molecular basis and after 16S rRNA sequencing, and 99% resemblance was observed with Enterobacter cloacae. FT-IR analysis of the bacteria illustrated the presence of functional groups, including hydroxyl, carboxyl group, sulfide, and amino groups, on the bacterial cell surface involved in the adsorption of lead. Moreover, electron microscopy (SEM) revealed the morphological and physiochemical changes in the bacterial cell after biosorption, indicating the interaction of Cu ions with functional groups. To summarize, the findings show the highly toxic effects of lead on animals and humans and its effective biodegradation by the bacterial strains in the lead-contaminated environment. This biological strategy can be an ideal alternative to remediate heavy metals from contaminated sites to clean up the environment.