Clinical and pathological effects of short-term cyanide repeated dosing to goats

Evaluation of the effective dose of amygdalin for the improvement of antioxidant gene expression and suppression of oxidative damage in mice

BACKGROUND

Little is known regarding the toxic and therapeutic doses of amygdalin. Treatment regimens and schedules can vary between humans and animal models, and there have been reports of cyanide toxicity due to amygdalin use.

OBJECTIVE

The aim of this study was to evaluate the effect of different doses of amygdalin on antioxidant gene expression and suppression of oxidative damage in mice.

METHODS

Forty adult male mice were divided randomly into four groups (n = 10) as follows and treated orally for two weeks: a control group treated with saline solution, a group treated with amygdalin at 200 mg/kg body weight, a group treated with amygdalin at 100 mg/kg body weight, and a group treated with amygdalin at 50 mg/kg body weight. Liver and testis samples were collected for gene expression, biochemical and histopathological analyses.

RESULTS

The mice treated with medium-dose amygdalin (100 mg/kg) showed upregulated mRNA expression of glutathione peroxidase (P < 0.01) and superoxide dismutase (P < 0.05) and significantly decreased lipid peroxidation (P < 0.05) in hepatic and testicular tissues compared to those in the untreated groups (controls), with mild histopathological effects. The mice treated with high-dose of amygdalin (200 mg/kg) showed downregulated mRNA expression of glutathione peroxidase and superoxide dismutase (P < 0.01) and significantly increased lipid peroxidation (P < 0.05) in both hepatic and testicular tissues compared to those in the untreated groups (controls), with an apparent effect at the histopathological level. No effects were observed in the mice treated with low-dose amygdalin (50 mg/kg) at the gene, protein and histopathological level.

CONCLUSION

Low-and medium-dose amygdalin did not induce toxicity in the hepatic and testicular tissues of male mice, unlike high-dose amygdalin, which had a negative effect on oxidative balance in mice. Therefore, amygdalin at a moderate dose may improve oxidative balance in mice.

Efficacy assessment of co-treated alpha-ketoglutarate and N-acetyl cysteine against the subchronic toxicity of cyanide in rats

Cyanide is an important industrial pollutant, major occupational hazard, and a potential chemical warfare agent. Its intentional or accidental exposure to humans is a big clinical problem because of its rapid mode of action. Certain plant origin foods also contain substantial amount of cyanide and cause chronic toxicity. This study explores the protective efficacy of co-treatment of alpha-ketoglutarate (AKG) and an antioxidant N-acetyl cysteine (NAC) against toxicity of subchronically exposed cyanide in rats. We explore the effect of AKG + NAC co-treatment on oxidative stress, inflammation, and histological changes induced due to long-term sublethal cyanide exposure. Cyanide induces oxidative stress by inhibiting metalloenzymes (catalase and superoxide dismutase) causing increase in lipid peroxidation (malondialdehyde) and decrease in reduced glutathione (GSH). It also increases the activity of cyclo-oxygenase enzymes causing oxidative stress-mediated inflammation in the brain. Cyanide exposure also causes degenerative changes in the brain as shown in histology. It also causes pathology in liver and kidney. AKG is known to form cyanohydrins with cyanide reducing the free cyanide levels, and its combination with NAC showed overall improvement in by reducing the oxidative stress and subsequent neuroinflammation. Their combination was also found to improve the histological outcome of vital tissues. AKG, an over-the-counter sport medicine, and the antioxidant NAC per se did not show any detrimental effects in any tested parameter. Hence, oral treatment with AKG and NAC can be beneficial for the treatment of chronic cyanide poisoning.

Cyanide toxicity and interference with diet selection in quail (Coturnix coturnix)

Cyanide is a ubiquitous substance in the environment. Most of the cyanide absorbed by an animal is detoxified by enzymatic combination with sulfur, thus the detoxification process imposes a nutritional cost. In mammals, interactions among nutrients and toxics may influence the composition of the diet and food intake, as a function of positive or negative post-ingestive feedback. The present work aimed to describe the toxic effects of cyanide, and to determine whether cyanide interferes with diet selection in quail (Coturnix coturnix). A toxicological study was performed with 27 female quails that were assigned to three groups that received by gavage 0, 1.0 or 3.0mg of KCN/kg/day, for 7 consecutive days. The diet selection trial was conducted with 20 female quails, that had access to two separate rations: a conventional quail ration and the same ration supplemented with 1% NaSO(4). During the toxicological study, clinical signs of poisoning and death occurred in a quail treated with cyanide. Histological changes were found only in animals dosed with cyanide, and these consisted of mild hepatic periportal vacuolation, an increased number of vacuoles in the colloid of the thyroid glands, and spongiosis in the mesencephalon. No clinical signs were found in any quail throughout the diet selection trial. There were no significant differences in food consumption or ration preference. In conclusion, exposure to cyanide promotes damage to the liver and central nervous system in quails. In contrast, the ingestion of sulfur by quail was not affected by exposure to cyanide.

Comparative effects of prolonged administration of cyanide, thiocyanate and chokecherry (Prunus virginiana) to goats

The aim of the present study was to determine and compare the clinical, hematological, biochemical and histopathological changes induced by cyanide, thiocyanate and chokecherry (Prunus virginiana) in goats. Sixteen Boer-Spanish cross-bred female goats were divided into four treatment groups: (1) control, (2) potassium cyanide (KCN) at 3.8 mg kg(-1) day(-1), (3) potassium thiocyanate (KSCN) at 4.5 mg kg(-1) day(-1) and (4) ground frozen chokecherry leaves and flowers at a target dose of 2.5 mg HCN kg(-1) day(-1), all for 4 weeks. Clinical signs were observed in two goats treated with chokecherry. Only sporadic changes were found in the hematological and blood chemical panel. Goats treated with chokecherry and thiocyanate had an increased number of vacuoles in the colloid of thyroid glands. Spongiosis and spheroids were found in the mesencephalon from goats treated with KCN and chokecherry. These findings suggest the thyroid lesions can be attributed to thiocyanate, whereas the effects on the nervous system were most likely caused by cyanide.