Iqbal Sayeed

Oxidative stress biomarkers of exposure to deltamethrin in freshwater fish, Channa punctatus Bloch

The pyrethroid class of insecticides, including deltamethrin, are being used as substitutes for organochlorines and organophosphates in pest-control programs because of their low environmental persistence and toxicity. Ecotoxicological consequences of deltamethrin, particularly its effects on antioxidants in fish and other aquatic organisms, are not well understood. We investigated the effect of deltamethrin (0.75 microg/L) on antioxidants in a freshwater fish, Channa punctatus Bloch, using standard laboratory conditions. A single exposure for 48 h caused induction of various antioxidant enzymes and nonenzymatic antioxidants in kidney and liver. The induction of these antioxidants was not very prominent in gills. In fact, certain antioxidants were found to be depleted in gills. Catalase activity was decreased in all the tissues. Deltamethrin also induced lipid peroxidation in all the tissues, gills showing the highest levels. Glutathione, which is an established nonenzymatic antioxidant in fish, was significantly (P<0.001) increased in all the tissues. Ascorbic acid content increased in kidney and liver while it decreased in gills. The findings of the present investigation show that deltamethrin has oxidative-stress-inducing potential in fish, and gills are the most sensitive organs. It is also interesting to note that gills are the primary sites of deltamethrin absorption and their antioxidant potential is also very poor. The various parameters studied in this investigation can also be used as biomarkers of exposure to deltamethrin. It is suggested that appropriate ecotoxicological risk assessment should be made in the areas where deltamethrin is proposed to be used in pest control activities.

Biomarkers of oxidative stress: a comparative study of river Yamuna fish Wallago attu (Bl. & Schn.)

Various oxidative stress biomarkers in gill, kidney and liver tissues in the Indian freshwater fish Wallago attu (Bl. & Schn.) were investigated. Fish were collected from two sites along the river Yamuna, which differ in their extent and type of pollution load. A comparison was made between the biomarker responses and general water chemistry at the two sites. The oxidative stress biomarkers that were analyzed included superoxide dismutase (SOD), catalase (CAT), xanthine oxidase (XOD) and glutathione redox cycle enzymes viz., glutathione peroxidase (GPx), glutathione reductase (GR) and glucose 6-phosphate dehydrogenase (G6PD). Levels of reduced glutathione (GSH) and lipid peroxidation (LPO) were also evaluated. All biomarkers; SOD (P<0.001 in liver, kidney and gill), XOD (P<0.01 in kidney and P<0.001 in liver and gill), GR (P<0.01 in liver, P>0.05 in kidney and P<0.001 in gill), G6PD (P<0.001 in liver, P>0.05 in kidney and P<0.01 in gill), GSH (P<0.001 in liver, kidney and gill) and LPO (P>0.05 in liver, kidney and gill) were found to be substantially higher in the fish collected from Panipat when compared with values in tissues of fish collected from Agra site. GPx and CAT showed a varied response. GPx activity was higher (P<0.001) in gills and kidney of the fish collected at Panipat site. However, liver showed significant low values (P<0.01) when compared with Agra site values. CAT activity was found to be significantly low, in both liver (P<0.01) and kidney (P<0.001) whereas in gills non-significant (P>0.05) low values were observed. Water chemistry data at two sites indicated that Panipat site with higher biochemical oxygen demand, chemical oxygen demand, pH and low dissolved oxygen was comparatively more polluted than Agra site. Industrial activity profile of both the sites also indicates that Panipat has vigorous industrial activity coupled with intensive use of chemicals in agricultural practices in Haryana state. The findings of the present investigation provide a rational use of oxidative stress biomarkers in aquatic ecosystem pollution biomonitoring. This is also the first such attempt reported from India.

IMMUNOMODULATORY EFFECTS OF FENUGREEK (TRIGONELLA FOENUM GRAECUM L.) EXTRACT IN MICE

Immunomodulatory activity of aqueous extract of Trigonella foenum graecum L., a widely used medicinal and dietary herb, was evaluated in male Swiss albino mice. Mice were treated with three doses of extract (50, 100 and 250 mg/kg body weight per os) for 10 days. Body weight, relative organ weight, cellularity of lymphoid organs, delayed type of hypersensitivity (DTH) response, plaque-forming cell (PFC) assay, haemagglutination titre (HT), quantitative haemolysis of SRBC (QHS) assay, phagocytosis, and lymphoproliferation were studied in various groups of animals. At doses of 50 and 100 mg/kg, a significant increase (p < 0.05) in relative organ weight of thymus was observed but there was no effect on kidney and spleen weights. Liver weight also increased significantly at doses of 100 and 250 mg/kg. However, no elevation in the levels of liver function test (LFT) enzymes was observed. As regards lymphoid organ cellularity, spleen recorded no significant increase at any dose, whereas cellularities of thymus and bone marrow were significantly increased. T. foenum graecum extract elicited a significant (p < 0.001) increase in the DTH response at doses of 50 and 100 mg/kg, but the change at higher dose of 250 mg/kg was not statistically significant. Humoral immunity as measured by PFC showed an elevated response at a dose of 100 mg/kg, but at 50 and 250 mg/kg, no significant effect was observed. In the HT test, plant extract also showed modulatory effect at all the doses. Plant extract elicited a significant increase in phagocytic index and phagocytic capacity of macrophages. Stimulatory response of plant extract was also observed in lymphoproliferation assay but the response was weak. Overall, T. foenum graecum showed a stimulatory effect on immune functions in mice. As it is used for a variety of medicinal purposes, its immunostimulatory effect, as reported in this study, strengthens the rationale of its use in several Ayurvedic and Unani drugs.

Pollutant-induced over-activation of phagocytes is concomitantly associated with peroxidative damage in fish tissues

Pollutant-induced abnormal functioning of phagocytes and associated consequences were studied in freshwater catfish Heteropneustes fossilis (Bloch). Fish were exposed to effluent collected from bleached kraft type of paper mill at the concentration levels of 0.5, 1 and 2% for 15, 30, 60 and 90 days. Respiratory burst activity of peritoneal and head kidney phagocytes of exposed fish was measured by nitroblue tetrazolium reduction assay. Lipid peroxidation (LPO) was estimated in liver, gill and kidney of fish by measuring thiobarbituric acid reaction substances. It was observed that the phagocyte-activating xenobiotics of effluent induced an increase in the respiratory burst activity in phagocytes. The induction of respiratory burst activity was concomitantly associated with an increase in the peroxidative damage of tissues. The tissues most affected were kidney and gills. The change in LPO values in the gills of exposed fish was concentration- and time-dependent, showing significant increases (P<0.05 to <0.001) in all the exposed groups as compared with control fish. An almost similar pattern of LPO was observed in head kidney tissue (P<0.05 to <0.001). As regards liver, increase in LPO was not widespread, except at 0.5% for 90 days (P<0.05). In fact, reduced rates of LPO were observed in the livers of some groups. The results of respiratory burst corroborate with the phagocytic activation as well as with the extent of lipid peroxidation in the tissues, showing high population of circulatory phagocytes. Our results demonstrate that fish of polluted water are subjected to oxidative stress of multifarious dimensions.

Dose-dependent protective effect of selenium in rat model of Parkinson's disease: neurobehavioral and neurochemical evidences

Normal cellular metabolism produces oxidants that are neutralized within cells by antioxidant enzymes and other antioxidants. An imbalance between oxidant and antioxidant has been postulated to lead the degeneration of dopaminergic neurons in Parkinsons disease. In this study, we examined whether selenium, an antioxidant, can prevent or slowdown neuronal injury in a 6‐hydroxydopamine (6‐OHDA) model of Parkinsonism. Rats were pre‐treated with sodium selenite (0.1, 0.2 and 0.3 mg/kg body weight) for 7 days. On day 8, 2 µL 6‐OHDA (12.5 µg in 0.2% ascorbic acid in normal saline) was infused in the right striatum. Two weeks after 6‐OHDA infusion, rats were tested for neurobehavioral activity, and were killed after 3 weeks of 6‐OHDA infusion for the estimation of glutathione peroxidase, glutathione‐S‐transferase, glutathione reductase, glutathione content, lipid peroxidation, and dopamine and its metabolites. Selenium was found to be successful in upregulating the antioxidant status and lowering the dopamine loss, and functional recovery returned close to the baseline dose‐dependently. This study revealed that selenium, which is an essential part of our diet, may be helpful in slowing down the progression of neurodegeneration in parkinsonism.

Aqueous extract of walnut (Juglans regia L.) protects mice against cyclophosphamide-induced biochemical toxicity.

Walnut (Juglans regia L.) is extensively used in traditional systems of medicine for treatment of various ailments. It is described as an anticancer, tonic, blood purifier and detoxifier agent. The present study was undertaken to investigate modulatory effects of walnut extract on the toxicity of an anticancer drug, cyclophosphamide (CP) with special reference to protection against disruption of drug metabolizing and antioxidant enzymes. Plant extract+CP group animals showed restoration in the level of cytochrome P450 (CYP) content and in the activities of glutathione S-transferase (GST), glutathione peroxidase (GP) and catalase (CAT) in both liver and kidneys. But plant extract restored the activity of super oxide dismutase (SOD) and the level of reduced glutathione (GSH) in the kidneys only when compared with CP-treated animals. Plant extract treatment alone caused significant reduction in the content of CYP in the kidneys mainly. The extract showed a significant increase in the level of GSH and in the activities of GP in both the tissues and CAT in liver only, whereas no significant change was observed in the activities of GST and SOD. CP treatment resulted in a significant (P<0.01) increase in the lipid peroxidation (LPO) in the liver and kidneys compared with controls, while the extract CP treated group showed a significant decrease in the LPO in liver and kidneys when compared with the CP-treated group. The study shows that the use of J. regia extract might be helpful in abrogation of CP toxicity during the chemotherapy.

Selenium-induced alteration of lipids, lipid peroxidation, and thiol group in circadian rhythm centers of rat.

The effect of sodium selenite (0.05, 0.1, and 0.2 mg/kg body weight, ip) on the contents of lipids (phospholipids, cholesterol, esterified fatty acids, gangliosides), thiobarbituric acid reactive substance (TBARS), and thiol group in circadian rhythm centers (preoptic area, brainstem, and posterior hypothalamus) of male Wistar rats was studied after 7 d of treatment. The content of phospholipids was elevated significantly with a dose of 0.1 mg/kg of selenite in the preoptic area and brainstem, but a 0.2-mg/kg dose has depleted its level significantly in these regions. The alteration of phospholipids in posterior hypothalamus was not significant with three doses of sodium selenite. The level of cholesterol in the preoptic area was inhibited significantly with a dose of 0.05 mg/kg sodium selenite, but its level was elevated significantly with a dose of 0.2 mg/kg selenite in the preoptic area and brainstem. Alteration with three doses of sodium selenite in the posterior hypothalamus was not significant. The ganglioside level in the preoptic area and brainstem was elevated significantly with a 0.1-mg dose of sodium selenite; conversely, a 0.2 mg dose of sodium selenite caused a significant depletion on its content in these areas. In the posterior hypothalamus, the ganglioside level was depleted significantly with a dose of 0.1 mg, but elevated significantly with a dose of 0.2 mg of sodium selenite. The level of esterified fatty acids was decreased significantly in the preoptic area and brainstem with a dose of 0.1 mg/kg sodium selenite, but in these regions, its level was elevated with a dose of 0.2 mg/kg sodium selenite and its elevation was significant in the preoptic area. In the posterior hypothalamus, the alteration of esterified fatty acids with three doses of sodium selenite was not significant. The effect of 0.1 and 0.2 mg/kg sodium selenite on the TBARS level and thiol group in sleep centers was significantly opposite to the wakefulness center. A sodium selenite dose of 0.1 mg/kg had depleted the content of TBARS in the preoptic area and brainstem but elevated the content of the thiol group significantly in the posterior hypothalamus. On the other hand, a 0.2-mg/kg dose of sodium selenite has significantly elevated the content of TBARS but depleted the content of the thiol group significantly in the posterior hypothalamus. No dose-dependent alteration was observed on the content of lipids, TBARS, and thiol group in the circadian rhythm centers of rats.

Modulatory effect of copper on nonenzymatic antioxidants in freshwater fish Channa punctatus (Bloch.).

Effect of the low level of copper exposure on nonenzymatic antioxidants was studied in a freshwater fish Channa punctatus (Bloch.). Fish were exposed to cupric chloride at the concentration of 10 ppb for 4 wk (28 d) in a static culture condition. Copper significantly (p < 0.001) increased the serum ceruloplasmin level and total iron-binding capacity. A significant (p < 0.05) increase in reduced glutathione level was recorded in all of the tissues. With regard to nonprotein thiols, copper decreased their level in the liver, but increased it in the gill. The protein-bound thiols remained unaltered except for an increase in the liver. Metallothionein (MT) induction was observed in liver only. Copper exposure had no significant effect on the ascorbic acid level and induced no lipid peroxidation over control values. It is suggested that by modulating the ceruloplasmin level, copper indirectly protects the fish, as it facilitates conversion of pro-oxidant iron to nonoxidant iron. It also induces an array of antioxidants that may be beneficial to fish in the case of oxidative stress resulting from chemical pollutants.

Protective effect of adenosine in rat model of Parkinson's disease: neurobehavioral and neurochemical evidences.

Normal cellular metabolism produces oxidants which are neutralized within the cell by antioxidant enzymes and other antioxidants. An imbalance between oxidant and antioxidant has been postulated to lead the degeneration of dopaminergic neurons in Parkinsons disease. In this study, we examined whether adenosine, an antioxidant, can prevent or slowdown neuronal injury in 6-hydroxydopamine (6-OHDA) model of Parkinsonism. Rats were treated with adenosine (500, 250, 125 mg/kg b.wt.) once before surgery and five times after surgery (1 h interval). 2 microl 6-OHDA (12.5 microg in 0.2% ascorbic acid in normal saline) was infused in the right striatum. Two weeks after 6-OHDA infused rats were tested for neurobehavioral activity and sacrificed after 3 weeks of 6-OHDA infusion, for the estimation of glutathione peroxidase, glutathione-S-transferase, glutathione reductase, glutathione content, lipid peroxidation and dopamine and its metabolites. Adenosine was found to be successful in up-regulating the antioxidant status, lowering the dopamine loss and functional recovery returned close to the baseline dose. This study revealed that adenosine, which is an essential part of our body, might be helpful in slowing down the progression of neurodegeneration in Parkinsonism.

Sodium selenite stimulates neurobehavior and neurochemical activities in rats

The effect of 0.05, 0.1, and 0.2 mg sodium selenite/kg body weight ip on the activities of neurobehavioral, acetyl cholinesterase, monoamine oxidase, and the content of dopamine and its metabolites in circadian rhythm centers of male Wistar rats was studied after 7 d of treatment. The results show an appreciable increase in locomotion, stereo-events, distance traveled, and average speed at the dose of 0.1 and 0.2 mg sodium selenite/kg. The data have shown hyperactivity of animals with various doses of sodium selenite, and it was significant and dose-dependent after 3 d of treatment. The activity of acetylcholinesterase (AChE) was inhibited dose dependently, and it was significant in preoptic area with 0.1 or 0.2 mg sodium selenite/kg. Conversely, in the posterior hypothalamus its activity was significantly elevated with the dose of 0.2 mg sodium selenite/kg, but its alteration in brain stem was not significant. Monoamine oxidase (MAO) activity was increased in preoptic area with the dose of 0.1 mg sodium selenite/kg, but its alteration in posterior hypothalamus and brain stem was not significant. The content of dopamine (DA), 3,4-dihydroxyphenyl acetic acid (DOPAC), and homovanilic acid (HVA) was elevated dose dependently and it was significant with the doss of 0.1 and 0.2 mg sodium selenite/kg, but the content of DOPAC and HVA in posterior hypothalamus was not significant with the dose of 0.1 mg sodium selenite/kg.