Keap1/Nrf2 pathway in sodium fluoride-induced cardiac toxicity and the prophylactic role of vitamin C versus platelet-rich plasma.

BACKGROUND: The present study was conducted to investigate the role of vitamin C versus platelet-rich plasma (PRP) against sodium fluoride (NaF)-induced cardiotoxicity and cell death in rats' myocardium. Previous studies suggest that NaF decreased cellular viability and intracellular antioxidant power. MATERIALS AND METHODS AND RESULTS: The present study revealed that NaF administration caused histological alterations in the cardiac muscle and increased the accumulation of intracellular reactive oxygen species, the expression of inducible nitric oxide synthases and proliferating cell nuclear antigen as well as collagen deposition in cardiac tissue. As supported by colorimetric analysis, an elevation in malondialdehyde level and a decrease in both superoxide dismutase (SOD) and thioredoxin-1 oxidoreductase (TrX) levels were seen, whereas molecular analysis revealed a decrease in Keap1 and an increase in Nrf2 and HO-1 gene expression. Pretreatment with vitamin C and PRP prior to NaF administration significantly improved the altered parameters and enhanced the cellular antioxidant capability of myocardium resulting in protection of cardiac muscle from NaF-induced cytotoxicity and apoptotic cell death. CONCLUSIONS: The cyto-protective activity of PRP was found to be comparable to that of the known antioxidant, vitamin C.

Can constant light exposure affect the thyroid gland in prepubertal male albino rats? Histological and ultrastructural study.

BACKGROUND: Through scientific literature, there is evidence that light affects thyroid function in human, mice and rabbits. Constant light and sleep deprivation is also used as a form of human torture, as it has impact on cognitive performances. The present work was conducted to study the effect of constant light for short and long periods on the thyroid gland in the prepubertal male albino rats. MATERIALS AND METHODS: A total of 30 prepubertal male albino rats were used. The rats separated into three groups: group I (control); group II were those rats put under steady encompassing light (24 h/day, light intensity of 600 lux) for 4 weeks; and group III were the rats maintained in constant light for 3 months. The rat thyroid gland was subjected to histological and ultrastructural examination. RESULTS: The rats exposed to light for long durations showed disturbed architecture; the follicles exhibited back to back arrangement (signs of hypertrophy with hyperplasia), lined by multiple layers of follicular cells or were lined by vacuolated cells. Few thyroid follicles exhibited cystic hyperplasia. Congested blood capillaries were demonstrated between the follicles. CONCLUSIONS: It can be concluded that the short-term exposure to constant light for 1 month had no apparent effect on thyroid gland tissues while longer exposure to light for 3 months had detrimental effects on the thyroid gland structure of male albino rats.

Effects of nicotine on rat adrenal gland: crosstalk between oxidative and inflammatory markers, and amelioration by melatonin.

Although the risks of smoking are well known, the effects of exposure to nicotine on endocrine functions remain unclear. We investigated the deleterious effects of nicotine on the adrenal gland and the mechanisms of these changes in rats. The role of melatonin in ameliorating pathological changes also was investigated. We used 24 rats divided into four groups of six: group 1, control; group 2, nicotine treated; group 3, nicotine and melatonin treated; group 4, melatonin treated. We used histology; immunohistochemistry of inducible nitric oxide synthase (iNOS), vascular endothelial growth factor (VEGF) and tyrosine hydroxylase (TH); measured oxidative and antioxidative markers, malondialdehyde (MDA) and glutathione (GSH); and performed real-time PCR for NF-κB 65, IL1-B and IL6. We also performed histomorphometric analysis. Indentation and lamellar separation of the adrenal capsule, vacuolated degenerated cells and lymphocytic infiltration were observed in group 2. Vacuolated cells and cells with pyknotic nuclei also were detected in the zona reticularis and medulla of the same group. We observed improved shape and cellular lining of the gland in groups 3 and 4. Widespread expression of iNOS, VEGF and TH, increased area percent collagen, decreased GSH (56%) and increased MDA, NF-κB, IL1-B and IL-6 were observed in group 2. All parameters were ameliorated in groups 3 and 4. The effects of nicotine on the adrenal gland can be attributed to oxidative and inflammatory stress; melatonin ameliorates these effects.