The Effects of Flaxseed Oil on Cadmium Induced Oxidative Stress in Rats

January 1, 2013 Human Health and Nutrition Data 0 Comments

The Effects of Flaxseed Oil on Cadmium Induced Oxidative Stress in Rats

Year: 2013
Authors: Karaca, S. Eraslan, G.
Publication Name: Bio. Trace Elem Res.
Publication Details: DOI 10.1007/s12011-013-9804-7


In the present study, the effects of flaxseed oil on the oxidant–antioxidant system in cadmium intoxication were investigated in rats. Forty-eight male Wistar albino rats were divided into four equal groups (group 1). No treatment was applied to the control group. On the other hand, groups 2, 3, and 4 were administered with 0.1 ml/rat/day (500 mg/kg bw) flaxseed oil by gavage into the stomach, 50 ppm of cadmium (4 mg/kg bw) in ad libitum drinking water, and 0.1 ml/rat/ day flaxseed oil plus 50 ppm of cadmium, respectively, for 30 days. At the end of the study, malondialdehyde and nitric oxide levels and catalase, superoxide dismutase, and glutathione peroxidase activities were measured in blood and tissue (liver, lung, kidney, brain, heart, and testes) samples. While malondialdehyde and nitric oxide levels increased in the group given cadmium compared to the control group; in the meantime, there were some significant changes in antioxidant enzyme activities. These changes were observed, the trends of decrease or increase compared to the control group. There were positive changes in parameters of the group given with flaxseed oil plus cadmium compared to the group receiving cadmium alone, in other words, values were seen coming close to control group. As a result, cadmium exposure caused oxidative damage to erythrocytes and organs at varying rates, while flaxseed oil reduced the severity of cadmium-induced lipid peroxidation. Therefore, it was concluded that flaxseed oil can be used among compounds as a therapeutic agent or food additive for prophylaxis in cadmium intoxication. (Authors abstract)
Oxidative stress is formed due to disruption of the balance between the production of oxidant compounds and antioxidant defense system. Of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) play key roles in the regulation of oxidant/ antioxidant balance. Several products are generated during lipid peroxidation. The most commonly employed markers for this purpose are malondialdehyde (MDA) and nitric oxide (NO). The changes in activities of antioxidant enzymes in biological systems also provide ideas on the level of oxidative stress.
There have been recent studies related to flaxseed oil and metal intoxication that particularly emphasize its effects against oxidative stress. In this study, rats were given cadmium for 30 days, and their side effects on a variety of tissues and erythrocyte have been examined on the basis of oxidative stress markers. In the group receiving cadmium, on the level of MDA, which is one of the indicators of lipid peroxidation, there has been an increase in all analyses sample (tissues and erythrocyte), which demonstrated that this compound, in the given dose and duration at the cellular level, disrupts the oxidant/antioxidant balance in favor of oxidants.  In this study, NO level has been found to be high not only in the tissues but also in the plasma. With regard to antioxidant enzyme activities in cadmium receiving group, there has been an increase or decrease change compared to control group. These changes have been remarkable in most of the tissues and erythrocytes which prove that in cellular level, high level of free radical generation is evident. SOD converts superoxide radical which is formed via different pathways to hydrogen peroxide, while CAT and GSH-Px are the antioxidant enzymes responsible for the degradation of hydrogen peroxide.   Cadmium causes enzyme inhibition by separating the iron in the catalytic subunit of CAT. Decline in activity observed in the samples may be related to this effect of cadmium. GSH-Px is also one of the antioxidant enzymes directly affected by cadmium. Cadmium causes this effect by depleting selenium. There was a fall in MDA and NO levels in the examined SOD, CAT, and GSH-Px activities, the values reached closer to control group values. Possible mechanism is a lowering of free radical level or scavenging of free radicals (OH radical in particular). The omega 3 fatty acids in flaxseed oil create protective effect against peroxidation by regulating fluidity of cell membrane and cell membrane enzymes. Flax oil also caused a decrease in MDA levels and positive changes in antioxidant enzymes. Flaxseed oil appears to supports antioxidant defense systems by triggering antioxidant enzymes response in some biological systems.
In conclusion, when administered at the specified dose for the specified period, cadmium led to a disruption of the prooxidant/ antioxidant balance in rats. In the groups receiving cadmium combined with flaxseed oil, oxidative stress was alleviated, thus potential side effects of cadmium have been mitigated. This is supported by the finding that there has been a fall in the levels of MDA and NO that are markers of oxidative stress, while antioxidant enzyme activities were coming close to control group values. Therefore, it was concluded that flaxseed oil could be used for supportive treatment in association with the primary treatment alternatives in cases of cadmium intoxication, and could also be used either directly or as a food additive for prophylaxis in case of intoxication risk. (Editors comments)

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