Parenteral aluminum compounds produce a local toxic myopathy in rats: importance of the anion

Bioactive compounds of African star apple (Chrysophyllum albidum G. Don) and its modulatory effect on metabolic activities linked to type 2 diabetes in isolated rat psoas muscle

The infusion of Chrysophyllum albidum was investigated for its antidiabetic mechanism by studying its ability to promote glucose uptake and utilization as well as its modulatory effect on metabolic activities linked to type 2 diabetes in isolated psoas muscle. Isolated psoas muscle was incubated with different concentrations of the infusion in the presence of glucose at 37°C for 2 hr. The infusion improved muscle glucose uptake, with concomitant elevated muscular levels of glutathione, superoxide dismutase, catalase, and ectonucleotidase activities, while depleting malondialdehyde, nitric oxide, adenosine triphosphatase, acetylcholinesterase, glycogen phosphorylase, glucose 6-phosphatase, fructose-1,6-biphosphatase, and lipase activities. It also maintained muscular morphology, while increasing magnesium, calcium, and iron levels. The infusion inhibited α-glucosidase and α-amylase activities in vitro. LC-MS analysis of the infusion revealed the presence of phenolics. These results indicate that C. albidum may mediate antidiabetic activities by stimulating muscle glucose uptake and modulation of key metabolisms linked to diabetes. PRACTICAL APPLICATIONS: The African star apple is among the underutilized fruits consumed for nutritional and medicinal purposes in Western Africa. The fruits are usually wasted during its season leading to postharvest loss owing to poor utilization. The present study gives credence to its use in treating diabetes and its complications. Thus, the fruits can be utilized in the development of cheap and affordable nutraceuticals for the management of diabetes which has been reported for its high-cost treatment. Utilization of the fruits will also reduce its postharvest loss and improve its economic values.

Aluminium toxicosis: a review of toxic actions and effects

Aluminium (Al) is frequently accessible to animal and human populations to the extent that intoxications may occur. Intake of Al is by inhalation of aerosols or particles, ingestion of food, water and medicaments, skin contact, vaccination, dialysis and infusions. Toxic actions of Al induce oxidative stress, immunologic alterations, genotoxicity, pro-inflammatory effect, peptide denaturation or transformation, enzymatic dysfunction, metabolic derangement, amyloidogenesis, membrane perturbation, iron dyshomeostasis, apoptosis, necrosis and dysplasia. The pathological conditions associated with Al toxicosis are desquamative interstitial pneumonia, pulmonary alveolar proteinosis, granulomas, granulomatosis and fibrosis, toxic myocarditis, thrombosis and ischemic stroke, granulomatous enteritis, Crohn's disease, inflammatory bowel diseases, anemia, Alzheimer's disease, dementia, sclerosis, autism, macrophagic myofasciitis, osteomalacia, oligospermia and infertility, hepatorenal disease, breast cancer and cyst, pancreatitis, pancreatic necrosis and diabetes mellitus. The review provides a broad overview of Al toxicosis as a background for sustained investigations of the toxicology of Al compounds of public health importance.

Fumonisin B1-induced DNA damage in rat liver and spleen: effects of pretreatment with coenzyme Q10, L-carnitine, alpha-tocopherol and selenium

Active oxygen radical species are reported to cause organ damage. This study was designed to determine whether oxidative stress contributed to the initiation or progression of hepatic and splenic cell DNA damage induced by fumonisin B1 (FB1) in rats. Another aim was to investigate the protective effects of the antioxidants coenzyme Q10 (CoQ10), L-carnitine, vitamin E (alpha-tocopherol) and selenium against DNA damage in the liver and spleen of rats treated with FB1. Fasted rats were injected intravenously with a single dose of fumonisin B1 at 1.55 mg kg-1 body wt. into the tail vein. Treatment with FB1 led to splenic and hepatic DNA fragmentation in 85% of the test animals. DNA fragmentation was investigated as a critical event in toxic cell death by testing total Ca2+ in liver. FB1 administration caused total Ca2+ in liver to increase within 4 h (204% of control). Measurement of liver enzyme activities showed an increase in aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT). FB1 also markedly decreased splenic and hepatic glutathione (GSH) levels. Pretreatment with CoQ10 (30 mg CoQ10 kg-1 diet) together with L-carnitine (2.8 mg carnitine kg-1 diet), alpha-tocopherol (30 IU vitamin E kg-1 diet) and selenium (1 mg selenium as sodium selenite kg-1 diet), decreased DNA damage and the activities of Ca2+, ASAT and ALAT in the liver. On the other hand, the level of GSH was slightly increased. The CoQ10 alone did not significantly protect against toxic cell death and glutathione depletion caused by FB1. Oxidative damage caused by FB1 may be one of the underlining mechanisms of FB1-induced cell injury and DNA damage.

Frequency and relationships of clinical chemistry and liver and kidney histopathology findings in 13-week toxicity studies in rats

The relative sensitivities of eight commonly used clinical chemistry end points and histopathology to detect potential toxic effects in liver and kidney were evaluated for a series of 61 13-week rat toxicity studies conducted for the National Toxicology Program. The data consisted of 1-,2- to 3-, and 13 week clinical chemistry measurements and 13-week histopathological assessments of liver and kidney. Except for serum alkaline phosphatase, treatment-related alterations of individual clinical chemistry variables occurred in 20-48% of the studies, depending on the analyte, sampling time, and sex. Liver and kidney lesions were reported for 31% and 41% of the studies respectively. There was an association between treatment-related increases in alanine aminotransferase (ALT) and sorbitol dehydrogenase (SDH) activities and histopathological changes in the liver. SDH activity had greater positive and negative predictive values than similar changes in ALT; by week 1 in females and weeks 2-3 in both sexes. SDH predicted morphological hepatic change at study termination with 75% or better accuracy. If increases in activities of both enzymes occurred simultaneously, however, terminal histopathological changes could be predicted, in both sexes, with 75% accuracy by week 1, increasing to 100% by weeks 2-3. There also was an association between treatment-related increases in urea nitrogen (UN) and creatinine (Cre) concentrations and morphological kidney change. Cre concentration had greater positive predictive values than similar changes in UN; by weeks 2-3 in males and week 13 in both sexes. Cre predicted morphological renal change at study termination with 56% or better accuracy. UN concentration was associated and predictive of morphological kidney change only in females at week 13. Depending on time point and sex, serum alkaline phosphatase activity increased in 5-22% of the studies. Increases in total bile acid concentration occurred in 33-48% of the studies. Because both tests are used as markers of cholestasis, this marked discrepancy was unexpected. Treatment-related decreases in alkaline phosphatase activity occurred, however, in 39-56% of the studies; serum alkaline phosphatase may be more useful as an indicator of decreased food intake (decreased activity) than of cholestasis (increased activity). In summary, treatment-related alterations of clinical chemistry and histopathology occurred frequently in this series of toxicity studies in rats. Changes in the chemistry end points also occurred frequently at interim time points, indicating that clinical chemistry evaluations can be useful for detecting potential treatment effects throughout a study. This observation is important, since histopathological evaluations are limited to animal termination and not useful for detecting transient responses or the onset of treatment-related effects.