Experimental Studying The Effects Of SBO And Sch-B On Cadmium-induced Hepatoxicity And Nephrotoxicity In Rats

IntroductionCadmium(Cd)is an important industrial and environmental pollutant that gets into our body by foods,water,smoking and the occupational exposure.The biologic half-life of cadmium is ten to thirty years.Cadmium is called as IA carcinogen that can induce cancer,deformity and mutation.Depending on the dose,route,and duration of exposure,Cd can cause damage to various organs including the lung,liver,bone, kidney and the immunologic system.Cadmium poses as a risk toxicant to the human by ATSDR.The mechanism of damage induced by cadmium is very complex and infected by various factors.Oxidative stress may be the crucial mechanism which contributes to Cd toxicity reported by a lot of correlative studies.The aims of the present studies are as follows:To study the effects of SBO,Sch-B on hepatoxicity of cadmium in rats and investigate the effects of SBO,Sch-B on nephrotoxicity of cadmium in rats.Materials and Method64 male and female Wistar rats,180±10g of weight,were purchased from Laboratory Animal Center in China Medical University.The animals were houses at 17～23℃and 45～55 percentage humidity.Rat chow was provided by Laboratory Animal Center.The animals were fed for seven days before experiment.The first part of experiment is to study the effects of Sea Buckthorn Oil(SBO)and Schisandrin B(Sch B)on hepatic injury induced by cadmium in vivo.32 of all the rats were divided into four groups at random:control group,cadmium group and SBO,Sch B pretreatment groups,8 in each group.The first and second groups were both given intragastrically with 0.9%NaCl.Two hours later,the first group were injected subcutaneously with 0.9%NaCl and the second were given subcutaneously with cadmium chloride(CdCl₂)35μmol/kg respectively.The third and fouth were pretreated respectively with SBO 5ml/kg and Sch B 20mg/kg first by intragastric administration, then injected subcutaneously with CdCl₂ 35μmol/kg two hours later.Liver and blood samples from the rats' abdominal aortae were collected.Activities of lactate dehydrogenase(LDH)and glutamate-pyruvate transaminase(GPT)in serum were determined.Levels of malonydialdehyde(MDA)and glutathione(GSH)and activities of glutathione peroxidase(GSH-Px),superoxide dismutase(SOD)in the liver were measured.The second part of experiment aim to study effects of SBO and Sch B on hepatoxicity and nephrotoxicity of cadmium in rats.Thirty-two adult Wistar rats were randomly divided into four groups.Control group was injected subcutaneously with 0.9%NaCl.Cadmium group and SBO,Sch B pretreatment groups were injected subcutaneously with cadmium chloride(CdCl₂)6μmol/kg,for up to 6 weeks.Then the two pretreatment groups were respectively given SBO 5ml/kg and Sch B 8mg/kg by intragastric administration for 2 weeks.Control group and cadmium group were given intragastrically with 0.9%NaCl at the same time.Urine and kidney cortex samples were collected in the end of the 8th week.Activities of lactate dehydrogenase(LDH), n-acetylglucosaminidase(NAG)activities and protein contents in urine,.Activities of LDH and GPT in serum were determined.malonydialdehyde(MDA)and glutathione (GSH)contents in renal cortex and liver as well as glutathione peroxidase(GSH-Px), superoxide dismutase(SOD)activities were measured.ResultThe first part of experiment:for the rats in acute exposure to cadmium,serum activities of LDH and GPT increased significantly,levels of MDA and GSH increased significantly,activity of GSH-Px and SOD activity declined sharply in the group exposed to Cd only.In acute experimentation,the SBO pretreatment group may sharply reduced the activities of LDH and GPT in serum,the MDA and GSH contents in liver to 71.5%(183.77,257.02)and 58.3%(15.83,27.13),74.8%(88.49,118.27)and 64.9%(6.81,10.49)respectively compared with Cd exposure group(p＜0.01),the activity of SOD in liver significantly increased.The second part of experiment:compared with the control group,the activities of LDH and NAG,the protein contents in urine,the LDH and GPT in serum,the contents of MDA and GSH in the kidney cortex and liver obviously increased.Adversely,the activities of GSH-Px and SOD reduced significantly in the group given Cd alone (p＜0.01).The contents of MDA and GSH increased sharply,the activities of GSH-Px and SOD in the kidney cortex and liver reduced significantly both in the SBO group and Sch B group(p＜0.05,p＜0.01).As compared with the rats treated with the sub-chronic exposure to Cd only,activities of GPT in serum,MDA and GSH contents in liver declined sharply,SOD increased significantly in the SBO group(p＜0.01). Compared to the acute and sub-chronic exposure to cadmium group,all the index of Sch B group had significance in statistics(p＜0.01,p＜0.05).Contrast with the Cd group,the activities of LDH and NAG,the protein contents in urine significantly reduced,MDA and GSH contents declined sharply,GSH-Px and SOD activities in kidney and liver cortex increased significantly in the SBO group as well as the Sch B group(p＜0.05,p＜0.01).ConclusionPretreatment with SBO,Sch B in rats could antagonize the acute and sub-chronic oxidative hepatic injury as well as nephrotoxicity induced by cadmium(35μmol/kg, 6μmol/kg,CdCl₂)to a certain extent.