Melatonin treatment suppresses appetite genes and improves adipose tissue plasticity in diet-induced obese zebrafish.

PURPOSE: Overweight and obesity are important risk factors for diabetes, cardiovascular diseases, and premature death in modern society. Recently, numerous natural and synthetic compounds have been tested in diet-induced obese animal models, to counteract obesity. Melatonin is a circadian hormone, produced by pineal gland and extra-pineal sources, involved in processes which have in common a rhythmic expression. In teleost, it can control energy balance by activating or inhibiting appetite-related peptides. The study aims at testing effects of melatonin administration to control-fed and overfed zebrafish, in terms of expression levels of orexigenic (Ghrelin, orexin, NPY) and anorexigenic (leptin, POMC) genes expression and morphometry of visceral and subcutaneous fat depots. METHODS: Adult male zebrafish (n = 56) were divided into four dietary groups: control, overfed, control + melatonin, overfed + melatonin. The treatment lasted 5 weeks and BMI levels of every fish were measured each week. After this period fishes were sacrificed; morphological and morphometric studies have been carried out on histological sections of adipose tissue and adipocytes. Moreover, whole zebrafish brain and intestine were used for qRT-PCR. RESULTS: Our results demonstrate that melatonin supplementation may have an effect in mobilizing fat stores, in increasing basal metabolism and thus in preventing further excess fat accumulation. Melatonin stimulates the anorexigenic and inhibit the orexigenic signals. CONCLUSIONS: It seems that adequate melatonin treatment exerts anti-obesity protective effects, also in a diet-induced obesity zebrafish model, that might be the result of the restoration of many factors: the final endpoint reached is weight loss and stabilization of weight gain.

Histological, morphometric, protein and gene expression analyses of rat retinas with ischaemia-reperfusion injury model treated with sildenafil citrate.

The aim of this study was to better understand the role of apoptosis in a retinal ischaemia-reperfusion injury model and to determine whether sildenafil citrate treatment can prevent retinal cell apoptosis. Thirty-six rats were divided into a control group (n = 6) and two experimentally induced ischaemia-reperfusion groups (7 and 21 days; n = 15 per group). The induced ischaemia-reperfusion groups were treated with sildenafil for 7 and 21 days (n = 10 per group), and 10 animals were treated with a placebo for the same period (n = 5 per group). Paracentesis of the anterior chamber was performed with a 30-G needle attached to a saline solution (0.9%) bag positioned at a height of 150 cm above the eye for 60 min. Intraocular pressure was measured by rebound tonometer (TonoVet® ). The eyes were analysed by histology and morphometry, and by immunohistochemistry and qRT-PCR for expression of Caspase-7, Caspase-6, Caspase-9, Tnf-r2, Fas-l, Bcl-2 and Bax. Sildenafil-treated animals showed lower levels of histopathological changes (inflammatory, cellular and tissue) than their placebo-treated counterparts at both 7 and 21 days. The retinal ganglion cell layer (RGC) was preserved in the sildenafil groups (SG), with a cell count closer to control than in the placebo groups (PG). Caspase-7 expression was significantly higher in both treated groups at 7 days compared to controls. Gene expression levels in both treatment groups differed from the controls, but in SG Bax and Caspase-6 expression levels were similar to control animals. These results suggest that the main mechanism of retinal cell death in this model is apoptosis, as there is an increase in pro-apoptotic factors and decrease in the anti-apoptotic ones. Also, sildenafil seems to protect the retinal ganglion cell layer from apoptosis. Cell survival was evident in the histological and morphometric analyses, and sildenafil treatment had a protective effect in the apoptosis pathways, with gene expression levels in SG similar to the controls.

Clindamycin and quinolone therapy for Bacillus anthracis Sterne infection in 60Co-gamma-photon-irradiated and sham-irradiated mice.

OBJECTIVES: Sublethal ionizing doses of radiation increase the susceptibility of mice to Bacillus anthracis Sterne infection. In this study, we investigated the efficacy of clindamycin in 60Co-gamma-photon-irradiated and sham-irradiated mice after intratracheal challenge with B. anthracis Sterne spores. Clindamycin has in vitro activity against B. anthracis and inhibits the production of toxin from other species, although no direct evidence exists that production of B. anthracis toxin is inhibited. METHODS: Ten-week-old B6D2F1/J female mice were either sham-irradiated or given a sublethal 7 Gy dose of 60Co-gamma-photon radiation 4 days prior to an intratracheal challenge with toxigenic B. anthracis Sterne spores. Mice were treated twice daily with 200 mg/kg clindamycin (subcutaneous or oral), 100 mg/kg moxifloxacin (oral), 50 mg/kg ciprofloxacin (subcutaneous) or a combination therapy (clindamycin + ciprofloxacin). Bacteria were isolated and identified from lung, liver and heart blood at five timed intervals after irradiation. Survival was recorded twice daily following intratracheal challenge. RESULTS: The use of clindamycin increased survival in gamma-irradiated and sham-irradiated animals challenged with B. anthracis Sterne in comparison with control mice (P < 0.001). Ciprofloxacin-treated animals had higher survival compared with clindamycin-treated animals in two experiments, and less survival in a third experiment, although differences were not statistically significant. Moxifloxacin was just as effective as clindamycin. Combination therapy did not improve survival of sham-irradiated animals and significantly decreased survival among gamma-irradiated animals (P = 0.01) in comparison with clindamycin-treated animals. B. anthracis Sterne was isolated from lung, liver and heart blood, irrespective of the antimicrobial treatment. CONCLUSIONS: Treatment with clindamycin, ciprofloxacin or moxifloxacin increased survival in sham-irradiated and gamma-irradiated animals challenged intratracheally with B. anthracis Sterne spores. However, the combination of clindamycin and ciprofloxacin increased mortality associated with B. anthracis Sterne infection, particularly in gamma-irradiated animals.