Meena Kataria

Influence of malathion pretreatment on the toxicity of anilofos in male rats: a biochemical interaction study.

Toxicity of organophosphates stems mainly from the accumulation of acetylcholine due to inhibition of acetylcholinesterase (AChE). The consequences of excess acetylcholine depend on the events initiated by the interaction of acetylcholine with cholinergic receptors. Lipid peroxidation (LPO) induced by organophosphates also seems to be mediated via cholinergic receptors. Anilofos is a widely used thionoorganophosphate herbicide, while malathion is a thionoorganophosphate insecticide. Thionoorganophosphates undergo mixed function oxidase (MFO)-catalyzed bioactivation to oxons and can induce cholinergic crisis in mammals. Thus, factors (e.g. exposure to certain xenobiotics) which alter the MFO activity, can be assumed to affect the toxicity of these organophosphates. It was investigated in rats if malathion as an inhibitor of MFO can alter the toxicity of anilofos, examining certain biochemical traits in blood, brain and liver. Malathion or anilofos and their combination did not produce any obvious signs of toxicity. Malathion did not alter the anticholinesterase action of anilofos in blood, brain and liver. LPO was increased in erythrocytes, brain and liver with anilofos or malathion and their combination. Production of lipid peroxide in brain of malathion-pretreated rats given anilofos was significantly greater than in rats given anilofos alone. Malathion decreased glutathione (GSH) contents of liver and blood. Glutathione-S-transferase (GST) activity was decreased in the liver with malathion and its combination with anilofos. Total adenosine triphosphatase (ATPase) activity was not affected. Activities of Mg(2+)-ATPase and Na(+)-K(+)-ATPase were increased in the liver and erythrocytes, respectively, with the pesticide combination. Protein level in plasma was decreased with malathion and its combination with anilofos, but only with the combination in the liver. Results of the study indicate that malathion pretreament may not essentially alter the anticholinesterase action of anilofos, but may enhance anilofos-mediated oxidative damage to rat brain.

Mangiferin protects the streptozotocin-induced oxidative damage to cardiac and renal tissues in rats

The role of oxidative stress in streptozotocin (STZ)-induced toxicity and its prevention by a xanthone glucoside, mangiferin was investigated. To induce diabetes mellitus, adult male Wistar rats were injected STZ intravenously at 55 mg/kg body weight. The effect of mangiferin (10 and 20 mg/kg, i.p., 28 days) was investigated in STZ-induced diabetic male rats. Insulin-treated rats (6 U/kg, i.p., 28 days) served as positive control. Diabetic rats given normal saline served as negative control. Normal rats that neither received STZ nor drugs served as normal control. On day 28, the diabetic rats showed significant increase in serum creatine phosphokinase (CPK) and total glycosylated haemoglobin. Kidney revealed tubular degeneration and decreased levels of superoxide dismutase (SOD) and catalase (CAT) with an elevation of malonaldehyde (MDA). Cardiac SOD, CAT and lipid peroxidation were significantly increased. Histopathological findings revealed cardiac hypertrophy with haemorrhages. Analysis of erythrocyte revealed significantly elevated levels of MDA with insignificant decrease in CAT and SOD. Repeated intraperitoneal injections of mangiferin (10 and 20 mg/kg) and insulin (6 U/kg) controlled STZ-induced lipid peroxidation and significantly protected the animals against cardiac as well as renal damage. From the study, it may be concluded that oxidative stress appears to play a major role in STZ-induced cardiac and renal toxicity as is evident from significant inhibition of antioxidant defence mechanism in renal tissue or a compensatory increase in antioxidant defence mechanism in cardiac tissue. Intraperitoneal administration of mangiferin exhibited significant decrease in glycosylated haemoglobin and CPK levels along with the amelioration of oxidative stress that was comparable to insulin treatment.

Role of oxidative stress in pathophysiology of peripheral neuropathy and modulation by N-acetyl-L-cysteine in rats.

Objectives: The objectives of this study were to examine the role of reactive oxygen species and oxidative stress in peripheral neuropathy and behavioural pain responses in experimentally induced chronic constriction injury (CCI) of sciatic nerve of rat. Effect of N‐acetyl‐l‐cysteine (NAC) administered intraperitoneally, was also investigated on CCI‐induced neuropathic pain in rats.

Changes in oxidative stress indices, zinc and copper concentrations in blood in canine demodicosis.

Status of certain oxidative stress indices and zinc and copper concentrations in blood were estimated in dogs with localized demodicosis (LD) and generalized demodicosis (GD). In comparison to healthy control, erythrocytic lipid peroxides level and superoxide dismutase activity were significantly (P<0.01) higher in both LD as well as GD. However, level of reduced glutathione and activity of catalase were significantly (P<0.01) lower in both LD and GD. Blood zinc and copper levels in dogs with LD and GD were significantly (P<0.01) lower than healthy control. Significant (P<0.01) differences were also observed in different oxidative stress indices and zinc and copper levels in between LD and GD groups. From the present study, it was concluded that demodicosis is associated with oxidative stress and antioxidant supplementation may be beneficial in management of canine demodicosis.

Effects of simultaneous repeated exposure at high levels of arsenic and malathion on hepatic drug-biotransforming enzymes in broiler chickens.

Groundwater contamination with arsenic is a major global health concern. The organophosphorus insecticide malathion has gained significance as an environmental pollutant due to its widespread use in agriculture, grain storage, ectoparasite control and public health management. The deleterious effects produced by arsenic or malathion alone are documented, but very little is known about the consequences of their coexposure. The aim of the current study was to examine the effects of repeated simultaneous exposure to arsenic and malathion on drug-biotransforming enzymes in the liver of broiler chickens. One-month-old broiler chickens were exposed daily to arsenic (50 ppm)-supplemented drinking water, malathion (500 ppm)-mixed diet or in a similar fashion coexposed to these agents for 28 days. At the term, changes in body weight, organ weights, and levels of hepatic cytochrome P450 (CYP), cytochrome b(5), microsomal and cytosolic proteins; aminopyrine N-demethylase (ANDM), aniline P-hydroxylase (APH), glutathione S-transferase (GST) and uridine diphosphate glucuronosyltransferase (UGT) were assessed. Arsenic, malathion or their coexposure decreased the body weight gain and liver weight. Brain weight (relative) was increased with arsenic or malathion, but not with the coexposure. Treatment with arsenic decreased the CYP and cytochrome b(5) contents by 39 and 36%, than with malathion by 54 and 22% and the coexposure by 45 and 28%, respectively. The ANDM activity was decreased with arsenic (44%), malathion (23%) and the coexposure (32%). Arsenic (23%) and the coexposure (37%), but not malathion (14%), reduced the APH activity. The activities of hepatic microsomal and cytosolic GST were increased with all the three treatments [Arsenic (microsomal: 88% cytosolic: 113%), malathion (microsomal: 137%, cytosolic: 94%) and coexposure (microsomal: 140%, cytosolic: 148%)]. These treatments did not significantly affect the hepatic UGT activity, but reduced the hepatic microsomal (arsenic: 28%, malathion: 34% and coexposure: 43%) and cytosolic (17-19%) protein contents. The effects of coexposure on the activities of various phase I and phase II drug-biotransforming enzymes were almost similar to that of arsenic or malathion. This study provides evidence that repeated coexposure to arsenic and malathion may influence the extent of drug metabolism in chickens.

Subchronic exposure to a mixture of groundwater-contaminating metals through drinking water induces oxidative stress in male rats.

The current study examines the oxidative stress-inducing potential of a mixture of metals, representative of groundwater contamination in different areas of India. Male albino rats were exposed to the mixture through drinking water for 90 days at 0, 1, 10 and 100 times the mode concentrations of the metals in contaminated waters and at concentrations equal to their WHO maximum permissible limit (MPL) in drinking water. The endpoints evaluated were lipid peroxidation (LPO), GSH content and activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase in heart, liver, kidney and brain. MPL and 1× levels did not induce any alterations. The mixture at 10× and 100× doses increased LPO and decreased GSH level and activities of the antioxidases in kidney, liver and brain, but no alterations were observed in heart. An inverse correlation between LPO and GSH or antioxidaes and a positive correlation between GSH and glutathione peroxidase or glutathione reductase were found in the affected organs. The findings suggest that the mixture induces oxidative stress and decreases antioxidant status in 10× and 100× the mode concentrations of the metals in drinking water.

Effects of Tinospora cordifolia supplementation on semen quality and hormonal profile in rams

The present study was undertaken to assess the effect of dietary supplementation of Tinospora cordifolia on physico-morphological, biochemical, antioxidant profiles and serum testosterone concentration in Muzzafarnagari rams. Twelve rams were randomly divided into two groups, control (n=6) and supplemental (n=6) group. The control group was fed with a diet satisfying NRC recommendations whereas the supplemental group was fed with T. cordifolia at the rate of 1g/kg body weight for 6 months. The semen samples were collected 60 days post-feeding. The result revealed that T. cordifolia supplementation did not have a significant effect on physico-morphological, biochemical attributes of semen and serum testosterone concentrations in rams. The concentration of cholesterol, superoxide dismutase (SOD) and catalase were, however, increased (P<0.05) in seminal plasma. It was concluded that the possible protective effects of T. cordifolia supplementation were enhancing antioxidant enzymes and cholesterol concentrations in semen which may be protected the spermatozoa during cryopreservation and thus enhancing fertility in farm animals.

Heterologous Expression and Functional Characterization of Matrix Metalloproteinase-11 From Canine Mammary Tumor

Matrix metalloproteinases (MMPs) are reported to be involved in tumor growth, apoptosis, angiogenesis, invasion, and development of metastases. These are zinc containing metalloproteases, known for their role in extracellular matrix degradation. MMP-11 (stromelysin3) is reported to be highly expressed in breast cancer, therefore it may act as marker enzyme for breast cancer progression. The present work was carried out to produce recombinant canine (Canis lupus familiaris) MMP-11 lacking the signal and propeptide in E. coli by optimizing its expression and purification in biologically active form and to functionally characterize it. A bacterial protein expression vector pPROEX HTc was used. The MMP-11 mature peptide encoding gene was successfully cloned and expressed in E. coli and the purified recombinant enzyme was found to be functionally active. The recombinant enzyme exhibited caseinolytic activity and could be activated by Trypsin and 4-Amino phenyl mercuric acetate (APMA). However Ethylene diamine tertra acetate (EDTA) inhibited the enzymes caseinolytic activity. The recombinant enzyme degraded extracellular matrix constituents and facilitated migration of MDCK (Madin-Darby canine kidney) cells through BD Biocoat Matrigel invasion chambers. These results suggest that in vivo MMP-11 could play a significant role in the turnover of extracellular matrix constituents.

A comparative study on expression profile of developmentally important genes during pre-implantation stages in buffalo hand-made cloned embryos derived from adult fibroblasts and amniotic fluid derived stem cells

Abnormal gene expression in somatic cell nuclear transfer embryos due to aberrant epigenetic modifications of the donor nucleus may account for much of the observed diminished viability and developmental abnormalities. The present study compared the developmentally important gene expression pattern at 4-cell, 8- to 16-cell, morula, and blastocyst stages of buffalo nuclear transfer (NT) embryos from adult fibroblasts (AFs) and amniotic fluid stem cells (AFSCs). In vitro fertilized embryos were used as control embryos. Alterations in the expression pattern of genes implicated in transcription and pluripotency (OCT4, STAT3, NANOG), DNA methylation (DNMT1, DNMT3A), histone deacetylation (HDAC2), growth factor signaling, and imprinting (IGF2, IGF2R), apoptosis (BAX, BCL2), oxidative stress (MnSOD), metabolism (GLUT1) regulation were observed in cloned embryos. The expression of transcripts in AFSC-NT embryos more closely followed that of the in vitro fertilized embryos compared with AF-NT embryos. It is concluded that AFSCs with a relatively undifferentiated genome may serve as suitable donors which could be reprogrammed more efficiently to reactivate expression of early embryonic genes in buffalo NT.

Activity of MMP-9 after repair of abdominal wall defects with acellular and crosslinked bovine pericardium in rabbit.

This study was undertaken for the identification of matrix metalloproteinases (MMPs) in extracts obtained from native, acellular and crosslinked bovine pericardium (in vitro), as well as in the plasma after implantation of these biomaterials in rabbits (in vivo). Native pericardium (NP) expressed a 72 kDa (MMP‐2) band; whereas, in acellular pericardium (AP) two bands (10 kDa and 92 kDa) of MMPs were observed of which, 92 kDa band was very faint. AP crosslinked with glutaraldehyde did not show any gelatinase activity and thus reflects the creation of new additional chemical bonds between the collagen molecules which has been effectively removed. Gelatin zymography showed only one major band of 92 kDa in all the implanted and untreated rabbit plasma, but the relative amount of 92 kDa was 1–2 times higher in acellular bovine pericardium implanted rabbits as compared to crosslinked and native groups. In NP group, the 92 kDa band was the dullest among the three groups. This indicated that the level of MMP‐9 corresponds to the degree of collagen degradation.