Attenuation of lead-induced oxidative stress in rat brain, liver, kidney and blood of male Wistar rats by Moringa oleifera seed powder.

Moringa oleifera is a tree belonging to Moringaceae family and its leaves and seeds are reported to have ameliorative effects against metal toxicity. In the present investigation, M. oleifera seed powder was tested against lead-induced oxidative stress and compared against meso-2, 3-dimercaptosuccinic acid (DMSA) treatment. Male Wistar rats (100-120 g) were divided into four groups: control (2000 ppm of sodium acetate for 2 weeks), exposed (2000 ppm of lead acetate for 2 weeks), Moringa treated (500 mg/kg for 7 days after lead exposure), and DMSA treated (90 mg/kg for 7 days after lead exposure). After exposure and treatment periods, rats were sacrificed and the brain was separated into cerebellum, hippocampus, frontal cortex, and brain stem; liver, kidney, and blood were also collected. The data indicated a significant (p<0.05) increase in reactive oxygen species (ROS), lipid perioxidation products (LPP), total protein carbonyl content (TPCC), and metal content of brain regions, liver, and kidney in the exposed group compared with their respective controls. In the blood, delta-amino levulinic acid dehydratase (ALAD) activity, RBC, WBC, hemoglobin, and hematocrit showed significant (p<0.05) decrease on lead exposure. However, administration of M. oleifera restored all the parameters back to control, tissue-specifically, and also showed improvement in restoration better than DMSA treatment, indicating reduction of the negative effects of lead-induced oxidative stress.

Ameliorative effects of Bacopa monniera on lead-induced oxidative stress in different regions of rat brain.

Bacopa monniera is a rejuvenating herb for brain cells enhancing learning and cognitive ability. In the present investigation, the ameliorative effects of Bacopa monniera were examined against lead-induced oxidative stress in different regions of rat brain. Male rats were divided into five groups: control (1000 ppm sodium acetate) and exposed (1000 ppm lead acetate) for 4 weeks; DMSA (Meso-2,3-Dimercaptosuccinic acid)-treated (90 mg/kg body weight/day); Bacopa monniera-treated (BM) (10 mg/kg body weight/day) and a combination of BM + DMSA for seven consecutive days after 4 weeks of lead exposure. After treatment, the whole brain was isolated by sacrificing rats and four regions were separated namely cerebellum, hippocampus, frontal cortex and brain stem. Results indicated a significant (p < 0.05) increase in reactive oxygen species (ROS), lipid peroxidation products (LPP) and total protein carbonyl content (TPCC) in association with tissue metal content in all the four regions of brain for exposed group compared with their respective controls. However, the lead-induced ROS, LPP, TPCC and tissue metal content were lowered on treatment with Bacopa monniera, almost reaching the control group values in all the above brain regions compared to DMSA and a combination therapy. Results suggest that Bacopa monniera can mitigate the lead induced-oxidative stress tissue specifically by pharmacologic interventions which encompass both chelation as well as antioxidant functions.

Influence of selenium (antioxidant) on gliclazide induced hypoglycaemia/anti hyperglycaemia in normal/alloxan-induced diabetic rats.

Oxidative stress is involved in diabetes mellitus and its complications. Since diabetes is a stress-related disorder, supplementation with antioxidants may improve the condition. The purpose of this study is to know the effect of oral administration of selenium on blood glucose and its influence on gliclazide induced hypoglycaemia/antihyperglycaemia in normal and alloxan-induced diabetic rats. Albino rats of either sex were divided into three groups of six each. Group-I/II/III were treated with selenium 1/2 TD (0.9 microg/200 g rat)/TD (1.8 microg/200 g rat)/2TD (3.6 microg/200 g rat), respectively. Later group II was treated with gliclazide TD (1.44 mg/200 g rat)/selenium TD + gliclazide TD with a washout period of 1 week between the treatments. Diabetes was induced by alloxan monohydrate 100 mg/kg body weight i.p. A group of six rats showing fasting blood glucose levels ranging from 175-250 mg/dl were selected for the study. Rats were treated with selenium TD, gliclazide TD and selenium TD + gliclazide TD with a washout period of 1 week between the treatments. Selenium 1/2 TD and TD produced hypoglycaemia while 2TD produced hyperglycaemia. The combination of selenium TD with gliclazide TD, significantly enhanced the glucose lowering effect of gliclazide in normal and diabetic rats.

Glutamic acid reverses Pb2+-induced reductions of NMDA receptor subunits in vitro.

The objective of this study is to determine the effects of Pb2+ on N-methyl-d-aspartate receptor (NMDAR) subunits--NR1C1, NR2A and NR2B in primary cultured neuronal cells. We hypothesize that L-glutamic acid (GA) reverses Pb2+-induced NMDAR damage. Neuronal cells were isolated from the fetus brain at 18-20th day of gestation of pregnant Sprague Dawley (SD) rats. All experiments were included three independent cell preparations (N=3). The neuronal cells were exposed to Pb2+ (10(-10), 10(-9), 10(-8) and 10(-7)M) for 24 h. Neurons were pretreated with NMDAR agonist--L-glutamic acid (GA) (200 microM) and antagonists dizocipine (MK-801, 50 nM) for 1h and then exposed to 10(-7)M of Pb2+ for 24 h. Finally, GA at 2, 0.2 and 0.02 mM was incubated with neurons prior to Pb2+ exposure. Aliquots of NR1, NR2A and NR2B proteins from cell homogenate were immunoprecipitated with protein A agarose and detected by Western blotting. The addition of GA unconventionally reversed the reductions of NMDAR by Pb at protein levels, whereas MK-801 exacerbated Pb2+-induced damage. The protection by GA against Pb2+-induced reduction of NMDAR was dose-dependent. These findings suggest that the administration of GA may be a potential approach to intervene the Pb2+-induced NMDAR alterations.

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).

Health hazards due to pollution of waters along the coast of Visakhapatnam, east coast of India.

Environmental pollution that renders waters along the coastline and beaches unsatisfactory for use by the general public has become a global health problem. This study was conducted to examine the effects of pollution of beach waters and sediment at seven selected locations receiving land drainage along a 45-km stretch of the east coast near Visakhapatnam, India. Pathogenic bacteria were identified using standard methods of culturing on selective media. The Pollution Index (PI) was determined as the ratio of fecal coliform/fecal streptococci. Protozoan cysts and helminth ova were also identified by microscopic examination of water after appropriate staining. The results suggested that the beach waters in Visakhapatnam are hygienically poor. A high PI of the water in Lawson's Bay indicated that the water was unsuitable even for noncontact recreation (boating, etc.). Pathogen densities dissipated considerably from the source to the low tide mark. Sediments had significantly higher bacterial and protozoan populations but pathogen concentrations were low except in heavily used areas. The general distribution pattern suggests that the nature of the sediment has a significant role in the retention of bacteria, protozoan cysts, and soil-transmitted helminths.

In vitro effect of lead on Na+, K+-ATPase activity in different regions of adult rat brain.

Lead interferes with cellular energy metabolism by inhibiting ATP (Adenosine triphosphate) synthesis and hydrolysis. This study was conducted to determine in vitro effects of lead on Na+, K+-ATPase activity in four regions of adult rat brain: the cerebellum, the hippocampus, the frontal cortex and the brain stem. Male rats (Wistar strain) weighing 125-150 g were sacrificed, whole brain excised and the four regions were isolated. Each tissue was homogenized separately in sucrose (0.25 M) and imidazole (10 mM) buffer (pH 7.5) and P2 fraction was prepared by following established methods. The activity of ATPase was determined by measuring inorganic phosphate (Pi) liberated from ATP hydrolysis. The delineation of Na+, K+-activated component of ATPase was obtained by the difference between total ATPase and Mg2+-ATPase using 1 mM ouabain. The P2 fraction was incubated with 0, 5, 10, 25, 50 and 100 microM of lead at 37 degrees C for 10 min. The enzyme activity was expressed as micromoles of Pi liberated/mg protein/hr. The results indicated a concentration-dependent and region-specific response to lead. In vitro lead at 50 and 100 microM significantly inhibited ATPase activity in all regions of the brain. It was also observed that in the control rats, the enzyme activity was high in cerebellum and hippocampus regions of the brain. In vitro dithiothreitol (DTT) protected the enzyme activity from IC50 lead in four regions of brain. In cerebellum and hippocampus, a 5 microM DTT provided 100% protection against IC50 lead. These results suggest that lead interferes with the ion transport mechanism and cellular energy metabolism of the brain and this effect is region specific.