The Protective Effect And Mechanisms Of Sagittaria Sagittifolia Against Cadmium-induced Acute Liver Toxicity

Cadmium, one of the most dangerous heavy metals, was documented as the sixth toxicant material detrimental to human being by Toxicological Management Committee of United States, and had been proved to possess acute and chronic toxicity to laboratory animals and human being. Cadmium had toxic effect to several kinds of organs, including liver, kidney, and sex organ. Many researches had illustrated that cadmium could induce acute liver toxicity, but the mechanisms of which had not been enunciated clearly up date. However, it had been addressed that various of procedures were involved in cadmium-induced liver toxicity, such as oxidative stress, interaction between cadmium and calcium, destruction of structure and efficiency of membrane, and proinflammatory cytokines induced by cadmium. Additionally, overexpression of proto-oncogene induced by cadmium during this procedure of acute liver toxicity likely contributed to carcinogenesis of cadmium. Sagittaria Sagittifolia was a kind of natural food, both for diet and medicine, contained many kinds of antioxidative mineral elements and vitamins. It had been characterized that Sagittaria Sagittifolia could enhance the defense system of antioxidation of body. Here, we were to demonstrate whether Sagittaria Sagittifolia could extenuate cadmium-induced acute liver toxicity, and by which mechanisms it worked. Thi\study was to provide the evidences to articulate mechanisms of cadmium-induced acute liver toxicity further more and exploit Sagittaria Sagittifolia as healthy food.1. Experimental DesignIn this research, we regarded Sagittaria Sagittifolia and cadmium as our studying factors, and Sprague-Dawley male rats as our studying object. We were to study the protective effect and mechanisms of Sagittaria Sagittifolia against cadmium-induced acute liver toxicity through pretreated with Sagittaria Sagittifolia to rats. The studying contents included following three aspects:(一) To articulate the nutritional basis of antioxidation of Sagittaria Sagittifolia by examine the contents of some mineral elements and vitamins of it, which were relative to antioxidation.(二) To assess the liver efficiency by measuring the activity of serum lactate dehydrogenase (LDH) and alanine aminotransferase (ALT); and to study the protective mechanisms of Sagittaria Sagittifolia against cadmium-induced acute liver toxicity by measuring serum nitric oxide (NO) concentration, liver glutathione (GSH) content, malondialdehyde (MDA) and cadmium content, liver superoxidatase activity, glutathione peroxidatase (GSH-px) and nitric oxide synthase activity, and the expression level of tumor necrosis factor- a (TNF- a ) in the liver.(三) To study the effect and mechanisms of cadmium-induced c-fos mRNA expression in liver by RT-PCR.-Ht Experimental contents(一) Measurement of mineral elements and vitamins relative to antioxidation of Sagittaria Sagittifolia.The Sagittaria Sagittifolia samples were fully nitrified, and all the organic compounds were destroyed. The contents of iron, manganese, zinc and copper were measured by flash atom absorptive spectrum method, and selenium by hydrogenaseinitiated atom absorptive spectrum method. The contents of vitamin E and vitamin C were also measured by instructions of them individually. The iron, manganese, zinc ,copper, selenium, vitamin E and vitamin C contents of Sagittaria Sagittifolia were 0.0074, 1.59, 0.24, 0.35> 0.23, 2.18, 4.75 (mg/lOOg) respectively. (2) Observance of the protective effect and mechanisms of Sagittaria Sagittifolia against cadmium-induced acute liver toxicity.In our study, 60 male Sprague-Dawley rats were randomly assigned into six groups, each of ten. The rats were pretreated intragastrically with 25%, 50%, 75% Sagittaria Sagittifolia extract (2ml/100g), vitamin E (50mg/100g) and distilled water once daily for ten days. Twenty-four hr after the last dosing, animals were administered with CdCb (20 n mol/kg) intraperitoneally, control animals were given distilled water only.