ObjectivesThe aim of this study was to investigate the effects of pinealectomy and melatonin treatment on the rat thymus gland characteristics, taking into consideration possible gender differences.Materials and methodsThirty adult Wistar rats of both sexes were divided into three groups. Group C and group PX served as control groups and included sham-pinealectomized and pinealectomized animals that were treated with 10% ethanol solution (0,1ml/daily, subcutaneous). Animals from third group (group PXM) underwent pinealectomy and seven days after surgery started receiving melatonin dissolved in 10% ethanol solution (3mg/kg/daily, subcutaneous). All animals were treated for 4 weeks.ResultsVolume density of the thymus cortex showed statistically significant (p<0,05) decrease while the volume density of the thymus medulla was increased in the pinealectomized compared to the sham-pinealectomized female rats. Numerical density of macrophages as well as the distribution of blood vessels showed no gender differences. The numerical density of lymphocytes was statistically significantly decreased in female in comparison to the male pinealectomized rats. Melatonin treatment was proved to cause reverse effects in the sense that the results from the melatonin treated group corresponded to the results obtained from the control group of animals.ConclusionThe results of this study suggest that the pinealectomy causes gender-related changes in the rat thymus. Short-term melatonin treatment showed reverse effect, equally in both sexes.

OBJECTIVES: Dinuclear ruthenium(II) Schiff base complex was selected for in vivo study among many other novel metal-based compounds, because of its previously proved in vitro anticancer and antibacterial properties. The aim was to investigate the potential toxicity of this compound in animal model through biochemical and histopathological assessment. METHODS: Adult Swiss albino mice of both sexes were divided into high-dose and low-dose group that received a single intraperitoneal dose of ruthenium complex (175 mg/kg and 25 mg/kg, respectively) and one control group (vehicle only). After a follow-up period of 14 days, animals were sacrifi ced to obtain blood samples and organs. RESULTS: The test compound was well tolerated in a low-dose group and did not cause any mortality. The histological fi ndings and serum biochemistry suggested a reversible character of alterations found in vital organs of this group. However, in the high-dose group, adverse effects were more severe and indicated dose and gender-related toxicity. CONCLUSION: Mild side effects found in a low-dose group together with excellent in vitro properties, made dinuclear ruthenium(II) Schiff base complex a promising candidate for further investigation and development as anticancer and antimicrobial agent (Tab. 4, Fig. 6, Ref. 32).

Microsurgical procedures are the treatment of choice of peripheral nerve injuries, but often fail to reach full functional recovery. Melatonin has neuroprotective actions and might be used as a possible proregenerative pharmacological support. Therefore, the aim of this study was to analyze the time-dependence of the neuroprotective effect of melatonin on the overall fascicular structures of both ends of the transected nerve. Sciatic nerve transection was performed in 34 adult male Wistar rats divided in four groups: two vehicle groups (N=7) treated intraperitoneally for 7 (V7) or 21 (V21) consecutive days with vehicle (5 % ethanol in Ringer solution) and two melatonin groups (N=10) administered intraperitoneally 30 mg/kg of melatonin for 7 (M7) or 21 (M21) consecutive days. At the end of the experiment, proximal stump neuroma and distal stump fibroma were excised and processed for qualitative and quantitative histological analysis. Intrafascicular neural structures were better preserved and the collagen deposition was reduced in the melatonin treated groups than in the vehicle groups. Myelin sheath regeneration observed through its thickness measurement was statistically significantly (p<0,05) more pronounced in the M21 (1,23±0,18 µm) vs. V21 group (0,98±0,13 µm). The mean volume density of the endoneurium was lower in both melatonin treated groups in comparison to the matching vehicle treated groups. Although not statistically different, the endoneural tube diameter was larger in both melatonin groups vs. vehicle groups, and the effect of melatonin was more pronounced after 21 days (24,97 % increase) vs. 7 days of melatonin treatment (18,8 % increase). Melatonin exerts a time-dependent proregenerative effect on nerve fibers in the proximal stump and an anti-scarring effect in both stumps.

Background: Zearalenone is a widely spread mycotoxin, contaminant of most cereal grains. It has uterotropic, estrogenic and anabolic activity in farm animals. The results are hormonal disbalances as hyperestrogenism, Zearalenone inhibits follicle-stimulating hormone production, thus supressing ovarian follicle development and ovulation. Also, it induces oxidative stress. Melatonin acts as a potent natural antioxidant and regulates the reproductive function by modification of steroidogenesis. Objective: The present study was conducted to provide detailed qualitative histological analysis of uterus of female rats treated with zearalenone and melatonin and contribute to better understanding of the topic. Methods: Forty adult, female Wistar rats were equally divided into five groups: Z group – zearalenone, 0,3 mg/kg, i.g.; M group – melatonin, 10 mg/kg, i.p.; ZM group –concomitant application of zearalenone and melatonin in the same dosing regimen, VZ group–zearalenone vehiculum/sunflower oil, i.g. and MZ group–melatonin vehiculum/5% ethanol in Ringer, i.p. Animals were treated daily for 28 consecutive days. After that period, all animals were sacrificed to obtain samples for qualitative histological analysis using the light microscope. Results: Zearalenone led to the alterations of the uterine structures, predominantly in the endometrium that were characterized by metaplasia and hypertrophy of the epithelial cells and hypercellularity of the stroma. In the myometrium, zearalenone induced hypertrophy and hyperplasia of the myocytes. Conclusion: Melatonin, when applied together with zearalenone, blocked the adverse effects of the zearalenone.