Experimental Study Of Rat Kidney Injury Caused By Diquat

Background:Diquat(DQ),chemical name:1,1'-ethylene-2,2'-dipyridine dibromide,is a rapid contact herbicide and plant dehydrator.It was first developed and applied in UK in 1957.DQ is the third largest herbicide in the world,inferior to glyphosate and paraquat.Paraquat has been banned or severely restricted in more than 20 countries because of its strong toxicity to human and animals.In 2012,the Ministries of Agriculture,Industry and Information and General Administration of Quality Supervision of China had jointly issued a notice to impose restrictive management measures on paraquat.Since July of 2014,it has been clearly stipulated that the registration and production license of paraquat are revoked,that is,the production of paraquat is prohibited.The sale and use of paraquat were stopped in China from July 1st,2016.Only the foreign registration and production for export use can be kept.Therefore,as a substitute for paraquat,diaquat was widely used in agricultural production in the past two years,and the number of patients with acute poisoning of diquat also increased year by year.The standard use of DQ is less harmful to human and animals,but accidental absorption through skin,mucosa or oral administration is highly toxic to human.It may cause acute poisoning,even death.Oral diquat poisoning,a part of was absorbed from the gastrointestinal tract into the blood,and then distributed to all organs,tissues throughout the body,including liver,kidney concentration is higher.Early gastrointestinal mucosal injury may occur,but it is slightly less severe than paraquat injury.Clinically,acute kidney injury,oliguria,anuria,multi-organ injury,shock,and even death may occur in the early stage of severe poisoning.The reports on the fatality rate of DQ poisoning at home and abroad are different.There is no specific antidote or specific treatment for the poisoning of DQ.Early toxicant removal is very important.The earlier the patient visits the doctor after poisoning,the sooner the patient is treated,the sooner gastrointestinal cleansing treatment is conducted,the earlier the blood purification treatment is performed,and the earlier glucocorticoid and organ function protection are applied,the more optimistic the prognosis may be.Therefore,for the treatment of the acute poisoning of DQ,timely and correct diagnosis and assessment in the early stage as well as prompt comprehensive treatment are particularly important.Although DQ poisoning can cause multiple organ function damage,it is especially serious for kidney,which is mainly related to the accumulation of DQ in liver and kidney and theexcretion from kidney after poisoning.The kidney is the main excretion organ ofhuman body and also the main target organ of poison attack.After DQ poisoning,toxic components cause damage and necrosis of renal tubular epithelial cells by rhabdomyolysis,oxidative stress and ischemic injury,resulting decrease of renalexcretion function and further accumulation of toxic substances,which is a vicious cycle.If not diagnosed and treated in time,the patient will be in danger.However,traditional AKI laboratory examination indicators,such as serum urea nitrogen(BUN)and serum creatinine(Cr),can only indicate renal damage when the renal tubular epithelial cells is reduced by 70%to 80%,which is harmful for early diagnosis of disease.To search for early and sensitive indicators of AKI is significant.This paper focuses on the study of the relationship between the concentration of NGAL,KIM-1 and TGF-?1 and the severity of renal injury after DQ poisoning,aiming at the early detection and intervention of renal damage to reduce the injury and death of patients with toxin poisoning.Objective:To establish an acute renal injury model of DQ poisoning in rats,and to study the changes of blood concentrations of NGAL,KIM-1,TGF-?1 in the poisoned rats at different periods.Methods:180 rats were randomly divided into two groups after being raised for 1 week.One group was the DQ poisoning group,while 140mg/kg DQ(1/2 of LD50)was diluted with distilled water to 1ml and administered to rats' stomachs.The other group was the normal control group while 1ml normal saline was administered.Two groups of animals were anesthetized by intraperitoneal injection with 10%chloral hydrate(dosage according to the 3 ml/kg)at 30 minutes,2 hours,6 hours,24 hours,3 days,7 days,14 days,21 days,28 days respectively after gastric gavage.The blood levels of NGAL,KIM-1,TGF-?1 were detected and the expressions of those in kidney tissues were measured by Western blot.Lung and kidney tissues were collected for routine pathological examination and electron microscopy.Results:1.Changes of biochemical indexes in serum of rats in the poisoning group:The level of serum UA,BUN and Cr increased in the poisoning group.UA and Cr were both augmented in half an hour after PQ poisoning.UA reached peak in 24h and continued higher than the control group at the 14th day while Cr reached peak at the 7th day and then gradually declined.It was with no significant difference with the control group till to the 28th day.The level of BUN increased in 6h after exposure,and reached peak between the 7th and 14th day,and then decreased gradually.2.Changes of related proteins in serum of rats in the poisoning group:The NGAL increased at 0.5h and peaked at 24h,and continued to increase at the 3rd,7th and 14th day.It began to decline at the 21th day.KIM-1 began to rise in 0.5h.It kept peak at the 24h,3rd day and 7th day and declined at the 14th day which was still higher than control group and gradually reduced at the 21th day and 28th day.TGF-?1 did not change significantly.3.By routine pathological observation of HE,MASSON and electron microscopy,renal tissue damage was obvious and progressively aggravated in the early stage and recovered slowly in the later stage.Inflammatory infiltration of lung tissue was observed with no obvious fibrosis.4.Western blot test result:The expression of TGF-? in the renal tissue of the poisoning group has no significant increase compared to the control group.The NGAL started to rise at 2h and peaked in the 7-14th day.It gradually declined in the 21th day.The KIM-1 began to rise at 2h but transiently decreased at 6h and 24h.With an increase in the 3rd and 7th day again,it began to decrease gradually.Conclusion:NGAL and KIM-1 were early indicators with rapidity,sensitivity and accuracy to DQ poisoning induced AKI.There was no significant change in the blood and tissue of TGF-?1 concentration that indicated the risk of tissue fibrosis induced by DQ poisoning was low.