Assessment of cytotoxic and clastogenic effects of nimesulide: an NSAID drug in somatic cells of BALB/c mice in vivo

Cerebrovascular Injury After Serial Exposure to Chronic Stress and Abstinence from Methamphetamine Self-Administration

Cerebrovascular damage caused by either exposure to stress or the widely abused drug, methamphetamine (Meth) is known but stress and drug abuse frequently occur in tandem that may impact their individual cerebrovascular effects. This study examined their co-morbid cerebrovascular effects during abstinence from self-administered Meth after the exposure to chronic unpredictable stress (CUS). Exposure to CUS prior to unrestricted Meth self-administration had no effect on Meth intake in rats; however, the pro-inflammatory mediator cyclooxygenase-2 (COX-2) and the breakdown of cell-matrix adhesion protein β-dystroglycan in isolated cerebral cortical capillaries were increased after 3 days of abstinence and persisted for 7 days. These changes preceded decreases in occludin, a key structural protein component of the blood-brain barrier. The decrease in occludin was blocked by the COX-2 specific inhibitor nimesulide treatment during abstinence from Meth. The changes in COX-2, β-dystroglycan, and occludin were only evident following the serial exposure to stress and Meth but not after either one alone. These results suggest that stress and voluntary Meth intake can synergize and disrupt cerebrovasculature in a time-dependent manner during abstinence from chronic stress and Meth. Furthermore, COX-2 inhibition may be a viable pharmacological intervention to block vascular changes after Meth exposure.

A toxicology study to evaluate the embryotoxicity of metformin compared with the hypoglycemic drugs, the anticancer drug, the anti-epileptic drug, the antibiotic, and the cyclo-oxygenase (COX)-2 inhibitor

BACKGROUND

The safe use of medications in pregnant females, their embryos and in offspring is important. The aim of the present study was to evaluate embryotoxicity of metformin (MET) compared with other hypoglycemic drugs (rosiglitazone [RSG] and glimepiride [GLIM]), the anticancer drug 5-fluorouracil (5-FU), the anti-epileptic drug diphenylhydantoin (DPH), the antibiotic penicillin G (PenG), and the cyclo-oxygenase (COX)-2 inhibitor nimesulide (NIM) in an embryonic stem cell test (EST).

METHODS

Differences in the expression of developmental marker genes following treatment with the test compounds during the course of differentiation (from embryonic stem cell D3 (D3 cells) to myocardial cells) were determined using real-time quantitative polymerase chain reaction. In these studies, 5-FU was used as a positive control and PenG was used as a negative control. The cytotoxicity of these drugs against D3 cells and 3T3 fibroblasts was determined by the 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Embryotoxicity was classified according to the prediction model of EST.

RESULTS

At concentrations >800 μg/mL MET had a greater cytotoxic effect on D3 cells than 3T3 fibroblasts. At the highest concentration of MET (5 mg/mL), the cell viability of D3 cells and 3T3 fibroblasts was <10% and >30%, respectively. The size of the embryonic body (EB) differentiation area was almost the same over the concentration range 50-200 μg/mL MET, and there was no significant difference in EB differentiation area until a concentration of 400 μg/mL MET. At a concentration of 800 μg/mL MET, the size of EB outgrowth was significantly reduced. The same assays revealed GLIM, RSG, and NIM to be weakly embryotoxic substances.

CONCLUSIONS

Based on the EST, MET can be classified as a weakly embryotoxic substance, which suggests that it should be prescribed with caution to pregnant women with gestational diabetes.

Genotoxicity of nimesulide in Wistar rats

It is mandatory for all new drugs to be tested for their potential genotoxicity in addition to general toxicity testing. Some old drugs have not been tested adequately for their genotoxic effects because these were in use before the local regulations were enforced. According to the material safety database, the toxicological effect of nimesulide is not yet fully understood. The present study therefore aimed to explore the genotoxic potential of nimesulide in Wistar albino rats. Nimesulide at the dose level of 50 (Gr-50), 100 (Gr-100) and 200 (Gr-200) mg/kg body weight (b.w.) was given orally. Each rat in treated groups (Gr-50 to Gr-200; n = 10) and negative control group (Gr-NC; n = 10) were administered orally (p.o.) with nimesulide and normal saline, respectively, for 14 days. Similarly, rats of positive control (Gr-PC; n = 10) were administered with cyclophosphamide (CPA; 20 mg/kg b.w.) intraperitoneally. CPA served as positive control, whereas normal saline served as as negative control. Approximately 1-2 mL of blood was collected from retro-orbital sinus for comet assay and subsequently rats were sacrificed to aspirate the femoral bone marrow for the micronucleus test. Structural chromosomal aberration, micronucleated polychromatic erythrocytes (MnPCEs), polychromatic erythrocytes (PCEs) and comet tail length were calculated using micronucleus assay and comet assay, respectively, which served as markers of genotoxicity. In the present study, it was observed that a significant increase in (1) different classified structural chromosomal aberrations with increase in nimesulide dose, such as gaps (50 mg/kg), gaps, breaks and pulverizations (100 mg/kg) and gaps, breaks, fragments, rings and pulverizations (200 mg/kg) and (2) % MnPCE and comet tail length was observed in animals treated with CPA (p < 0.001) or 200 mg of nimesulide (p < 0.05), as compared to negative control. In conclusion, nimesulide (200 mg/kg b.w.) produced a potential genotoxicity in rats.

Rehabilitating a brain with Alzheimer's: a proposal

Alzheimer's disease (AD) is the most common neurodegenerative disorder, originating sporadically in the population aged over 65 years, and advanced age is the principal risk factor leading to AD development. In spite of the large amount of research going on around the globe and all the information now available about AD, there is still no origin or triggering process known so far. Drugs approved for the treatment of AD include tacrine, donepezil, rivastigmine, galantamine, and memantine. These may delay or slow down the degenerative process for a while, but they can neither stop nor reverse its progression. Because that this might be due to a lack of effect of these drugs on degenerating neurons, even when they are able to potentiate the brain in nondegenerative conditions, we propose here an alternative therapy consisting of initial repair of neuronal membranes followed by conventional drug therapies. The rehabilitation of neurons in a degeneration process would enable the drugs to act more effectively on them and improve the effects of treatment in AD patients.