The Protective role of selenium in preventing tissue damage induced by diazinon in rats

Background and Diazinon (DZN) is a commonly used organophos phorous (OP) pesticide. It is synthetic chemical substance with broad spectrum insecticide activity [3]. Toxic effects of diazinon are due to the inhibition of acetyl cholinesterase activity، an enzyme needed for proper nervous system function. It has been widely used throughout the world with applications in agricul ture and horticulture for controlling insects [4،5]. The Se is an essential dietary trace element which plays an important role in a number of biological processes [18] consists of antioxidant and anti mutagenic properties In the experiment، a total of 45 rats (200-250 gr) were used. The rats were randomly divided into 9 groups with five animals in each group. Animals were concurrently administered intraperitoneally with DZN in proper solvent (20 mg/kg body weight (b. w.)) and Se at three different doses (0. 5، 1، and 2 mg/kg b. w.) for 30 consecutive days. After necropsy، liver and kidneys of all animals were isolated and fixed in 10% buffered formalin. Using examples of common practices pathology tissue sections، 5 microns thick sections by microtome and prepared for staining with hematoxylin - eosin were prepared. In the liver of groups that diazinon had received، focal hepatic necrosis was created. Exposure also causes dilation of sinusoids in the liver parenchyma. Selenium in Dose of 0. 5mg / kg asthecontrolgroup، although high dose 2mg / kg causesfibrosisandfocalnecrosis، venous congestion and spasticitytic. Ingroups with diazinon received Selenium 0. 5 mg / kg lead toinflammatory cellinfiltrationin the portaltract and centralveindilatation. Together with theselenium 2 mg/kgdiazinoncausednecrosisand hepaticnecrosis inzone 3andspasticitytic. However،inthis study،diazinonwasinduced inflammation butnosignificantchangeinkidney of rat’s. necrosisanddestruction ofepithelial cellswere notobserved Thisstudy showed thatdiazinonhas theability to causeliver and kidneydamage، although the damage is less in kidney in comparison with liver damage. It was alsoobservedthatselenium in dose of 0. 5 mg / kg is able toreducethedamage; however the damage increased when the dose was increasing. It seems، selenium has a harmful role in increased doses، and it result to necrosis and fibrosis