George E. Eriyamremu

Levels of lipid peroxidation, superoxide dismutase, and Na+/K+ ATPase in some tissues of rats exposed to a Nigerian-like diet and cadmium

The purpose of the present study was to examine the role of a wholly compounded Nigerian-like diet on the activities of superoxide dismutase (SOD) and Na+/K+ ATPase and level of lipid peroxidation in oral cadmium toxicity. Nine-week-old Wistar albino rats (100±2.0 g) were exposed to 100 ppm cadmium in drinking water and the Nigerian-like diet (low in protein and high in carbohydrates and fiber) for 16 wk. The results obtained indicate that cadmium reduced weight gain and increased fecal output of rats, which was further potentiated by the Nigerian-like diet. Cadmium was concentrated in the intestine, liver, and kidney, with the highest level observed in the kidney, followed by the liver. The Nigerian-like diet reduced the concentration of cadmium in these tissues. Cadmium increased lipid peroxidation and inhibited SOD and Na+/K+ ATPase in the tissues. These were also aggravated in rats fed the Nigerian-like diet. Because the Nigerian-like diet increased lipid peroxidation and inhibited SOD and Na+/K+ ATPase in the tissue, it rendered rats more susceptible to cadmium toxicity.

Palm oil induced changes in ocular tissue lipid peroxidation, antioxidant enzymes and ATPases of rabbits in cadmium toxicity.

This study determined the effect of supplementing rabbit diet with palm oil (PO) on lipid peroxidation, antioxidant enzymes and ATPases of different sections of the eyes in ocular cadmium toxicity. Twenty male New Zealand rabbits were randomly assigned to 4 groups of 5 rabbits in a study that lasted for 4 weeks. The control was given deionised water as eye drops and the other groups of rabbits were given eye drops of solution of 2mgkg(-1) body wt cadmium (as 3CdSO(4).8H(2)O). One test group was fed with the normal chow alone and the other test groups were fed with the chow fortified with either 5% or 10% palm oil. Ocular treatment of rabbit with cadmium significantly (P<0.05) reduced their weight compared with the control. Feeding the animals with palm oil (PO) improved the weights of the animals and decreased cadmium accumulation in the eye tissues. Lipid peroxidation level was raised by cadmium in the cornea, lens and retina with palm oil supplementation of the animal diet significantly (P<0.05) reducing the level of lipid peroxidation of the retina. Cadmium significantly (P<0.05) reduced antioxidant enzymes and ATPases in the eye tissues compared with the control. Feeding the rabbits with PO significantly (P<0.05) increased the activities of these enzymes in the retina to levels comparable with the control, with the 10% supplementation producing a more pronounced effect. The study shows that PO can alter cadmium accumulation, antioxidant enzymes and ATPases in ways which suggest that it offers protection of the eyes from ocular exposure to cadmium.

Changes in carboxypeptidase A, dipeptidase and Na+/K+ ATPase activities in the intestine of rats orally exposed to different doses of cadmium.

The purpose of the present study was to evaluate the effect of cadmium on some protein digestive and absorption enzymes in rats. Thirty-six rats were grouped into three groups of 12 animals each; one group received deionised water and acted as control. One group received 445 µM Cd and the last group received 890 µM Cd in their drinking water for a period of one month. The results obtained indicate that increasing the level of cadmium from 445 µM to 890 µM in the drinking water of the rats led to 29 and 23 increase in accumulated cadmium in the proximal and distal small intestine respectively. The body weight gain of rats exposed to 445 µM and 890 µMCd was decreased by about 24 and 43 respectively when compared with the control. The activities of carboxypeptidase A, dipeptidase and Na+/K+ ATPase were reduced in the mucosa of the proximal end of the small intestine of cadmium exposed rats. The reduction was dose dependent; with the 890 µM Cd exposed rats displaying the least activities. In the distal small intestine, the activities of these enzymes were restored in the 445 µM Cd exposed rats to levels that were not statistically different (P>0.05) from those observed in the controls. In the 890 µMCd exposed rats, dipeptidase activity improved by about 80 compared with the activity of the enzyme in the proximal small intestine. Likewise, Na+/K+ ATPase activity increased by about 125 compared with the observed level in the proximal small intestine. The study suggests that cadmium given to rats in drinking water compromise protein digestion and absorption of nutrients particularly in the proximal region of small intestine and could account for weight reduction associated with cadmium toxicity.

Hypoglycaemic Effects of Viscous Preparation of Irvingia gabonensis (Dikanut) Seeds in Streptozotocin-Induced Diabetic Wistar Rats

ABSTRACT Although there has a been report on the antidiabetic effect of the seeds of Irvingia gabonensis in rats, the dose and mode of administration as a supplement of chow did not reflect the manner of consumption in West Africa. We therefore administered a total daily dose of 2 g/kg per os as a viscous form of the ground seeds at 12-h intervals to streptozotocin-induced diabetic rats. After three weeks, fasting blood glucose level, liver pyruvate kinase, lactate dehydrogenase and glucose-6-phosphatase activities were determined. Results indicate decreases in blood glucose (P < 0.05), pyruvate kinase and lactate dehydrogenase activities (P < 0.05); and a higher glucose-6-phosphatase activity (P < 0.05) in dikanut-fed diabetic rats compared with others not fed dikanuts. These indices were comparable between dikanut-fed diabetic and normoglycaemic control rats. It is concluded that the ground seeds of dikanuts prepared in stew form and eaten in large amounts may be a useful adjunct in the management of type-2 diabetes mellitus, particularly in cultures in which staple foods are carbohydrate-based.

Early changes in energy metabolism in rats exposed to an acute level of deoxycholate and fed a Nigerian-like diet.

Early alterations in cellular energy metabolism, reductive biosynthesis and enzymes related to cell proliferation were studied in 40 Wistar albino rats exposed to an acute level of deoxycholate (DOC), and fed different diets. The animals were divided into four equal groups and fed ad libitum either a normal diet (ND), a high-carbohydrate high-fibre (HCF) diet, or a high-protein high-fat (HPF) diet. Three times weekly intrarectal injection of 40 mg/0.2 ml DOC was given to three groups of the rats for 9 weeks. The specific activities of phosphofructokinase, pyruvate kinase, lactate dehydrogenase, glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were all significantly (p < 0.05) increased in the DOC-treated animals compared with the physiological saline-treated control. Reductive biosynthetic enzyme activities (malic enzyme, isocitrate dehydrogenase-NADP(+)-dependent, and ATP-citrate lyase) were reduced in the DOC-treated animals compared with the control. Feeding rats with the HCF diet significantly (p < 0.05) lowered the specific activities of the enzymes of glycolysis, of the pentose phosphate pathway (oxidative) and hyaluronidase and proteinase compared with those of the HPF-fed rats. These results show an altered enzymic profile in rats fed an HCF and an HPF diet compared with rats fed the ND and suggests a protective role of the HCF diet against the development of colon cancer.

Early Biochemical Events in Mice Exposed to Cycas and Fed a Nigerian-Like Diet

Changes in colonic faecal microflora, enzymes of colonic energy metabolism, of cell proliferation and lipid profile in the serum and colon were studied in 48 mice exposed to cycas and fed a Nigeria-type diet. The animals were divided into three diet classes of 16 mice per class, and each class of animals was fed ad libitum either a normal diet, a high-carbohydrate high-fibre (HCF) diet or a high-protein high-fat (HPF) diet. Each diet class was subdivided into two equal groups of 8 animals each. One group was fed a diet type (acted as the diet control) without cycas, and the other group was fed the corresponding diet with cycas. The study period lasted for 3 weeks. The colonic faecal materials were acidified in the HCF-fed mice compared with the other diet-fed mice. Faecal beta-glucuronidase activity was significantly (p < 0.05) increased in the cycas-fed mice compared with the diet controls. Feeding mice with the HPF diet significantly (p < 0.05) increased beta-glucuronidase and mucinase activities. Colonic phosphofructokinase, glucose 6-phosphate dehydrogenase, lactate dehydrogenase and hyaluronidase activities were also significantly (p < 0.05) elevated in the cycas-treated mice. Feeding mice with the HPF diet also significantly (p < 0.05) increased these enzyme activities. Mice fed with the HCF diet significantly (p < 0.05) lowered serum total cholesterol, triglyceride and colonic total lipid. Colonic phosphatidylethanolamine and phosphatidylcholine were significantly (p < 0.05) increased in the HPF-fed mice. This study shows that the HCF diet alters the colonic faecal environment, colonic energy metabolism and hyaluronidase activity in ways which suggest its protective ability against the development of colon cancer in mice.