Sex affects the response of Wistar rats to polyvinyl pyrrolidone (PVP)-coated silver nanoparticles in an oral 28 days repeated dose toxicity study.

BACKGROUND: Silver nanoparticles (AgNPs) are widely used in biomedicine due to their strong antimicrobial, antifungal, and antiviral activities. Concerns about their possible negative impacts on human and environmental health directed many researchers towards the assessment of the safety and toxicity of AgNPs in both in vitro and in vivo settings. A growing body of scientific information confirms that the biodistribution of AgNPs and their toxic effects vary depending on the particle size, coating, and dose as well as on the route of administration and duration of exposure. This study aimed to clarify the sex-related differences in the outcomes of oral 28 days repeated dose exposure to AgNPs. METHODS: Wistar rats of both sexes were gavaged daily using low doses (0.1 and 1 mg Ag/kg b.w.) of polyvinylpyrrolidone (PVP)-coated small-sized (10 nm) AgNPs. After exposure, blood and organs of all rats were analysed through biodistribution and accumulation of Ag, whereas the state of the liver and kidneys was evaluated by the levels of reactive oxygen species (ROS) and glutathione (GSH), catalase (CAT) activity, superoxide dismutase (SOD) and glutathione peroxidase (GPx), expression of metallothionein (Mt) genes and levels of Mt proteins. RESULTS: In all animals, changes in oxidative stress markers and blood parameters were observed indicating the toxicity of AgNPs applied orally even at low doses. Sex-related differences were noticed in all assessed parameters. While female rats eliminated AgNPs from the liver and kidneys more efficiently than males when treated with low doses, the opposite was observed for animals treated with higher doses of AgNPs. Female Wistar rats exposed to 1 mg PVP-coated AgNPs/kg b.w. accumulated two to three times more silver in the blood, liver, kidney and hearth than males, while the accumulation in most organs of digestive tract was more than ten times higher compared to males. Oxidative stress responses in the organs of males, except the liver of males treated with high doses, were less intense than in the organs of females. However, both Mt genes and Mt protein expression were significantly reduced after treatment in the liver and kidneys of males, while they remained unchanged in females. CONCLUSIONS: Observed toxicity effects of AgNPs in Wistar rats revealed sex-related differences in response to an oral 28 days repeated exposure.

Intestinal Morphology in Broiler Chickens Supplemented with Propolis and Bee Pollen.

The aim of this study was to determine the influence of dietary supplementation with propolis and bee pollen on the intestinal morphology and absorptive surface areas of chickens. Two hundred day-old Ross 308 chickens (100 male and 100 female) were equally allocated into five groups. Throughout the whole study, the control group of chickens was fed with a basal diet, while the experimental groups of chickens were fed with the same diet supplemented with propolis and bee pollen: P1 = 0.25 g of propolis/kg + 20 g of bee pollen/kg; P2 = 0.5 g of propolis/kg; P3 = 1.0 g of propolis/kg; P4 = 20 g of bee pollen/kg. The duodenal villi of chickens from all experimental groups were significantly higher and wider (p < 0.001), while their duodenal villi crypts were significantly deeper (p < 0.001) in comparison with these parameters in chickens from the control group. The villus height to crypt depth ratio, as well as the absorptive surface areas of broiler chickens, were significantly increased (p < 0.001) in experimental groups of chickens in comparison with the control group. These findings suggest that dietary supplementation with propolis and bee pollen has a beneficial effect on broilers chickens' intestinal morphophysiology.

Forgotten partners and function regulators of inducible metallothioneins.

Metallothioneins are peculiar cysteine rich, heat resistant, small cellular plasma proteins expressed through almost all life forms. The currently established biological functions of metallothioneins are the homeostasis of essential metals and protection against toxic transitional metals (TM) alongside defence from oxidative stress by direct scavenging of reactive oxygen and nitrogen species (ROS and RNS). In mammals, among the four main evolutionary conserved forms, only the ubiquitously expressed metallothionein 1 and 2 (here abbreviated as MT) are inducible by TM, oxidative stress, glucocorticoids and starvation among various other stimuli. However, more than sixty years after being discovered, metallothioneins still bear unresolved issues about their possible physiological function and regulation. The biological function of MTs has still not been associated with the in vitro-demonstrated capacity of MT interaction with cellular molecules glutathione (GSH) or adenosine triphosphate (ATP), or with the possibility of direct iron-MT binding in the reducing intracellular environment of some organelles, e.g. lysosomes. Iron as the most abundant cellular TM is also one of the main physiological sources of ROS. Moreover, iron exhibits strain, sex and age differences that reflected ROS generation and MT induction in (patho)physiology and toxicology studies. A recent study showed that iron sex differences follows expression of both ferritin and MT leading to wide implications from essential TM interconnectivity to aging. This review places emphasis on biochemically proven but physiologically ignored interactions of MT with iron to stimulate advanced research for establishing a wide frame of the biological roles of MTs important for health and longevity.

Influence of Dietary Supplementation of Propolis and Bee Pollen on Liver Pathology in Broiler Chickens.

One of the major problems in intensive breeding of chickens is liver damage. The objective of this study was to determine the influence of dietary supplementation with propolis and bee pollen on liver pathology in broiler chickens. The study was conducted on 200 Ross 308 chickens equally distributed by sex that were divided into five groups. Throughout the whole study, the control group of chickens was fed with a basal diet, while the experimental groups of chickens were fed with the same diet further supplemented with propolis and bee pollen, each supplement given separately or in combination in a certain proportion. The study showed that the clusters of lymphocytes in the hepatocytes, the vacuolar degeneration and necrosis of the liver parenchyma, the bile ductule hyperplasia, and the various forms of pathological changes in the liver arteries and veins were more frequent in liver tissue samples of the control group compared to liver tissue samples of all the experimental groups (p < 0.001). The study further showed that all the previously mentioned histopathological lesions of liver tissue were always more extensive in the liver tissue samples of the control group than in the liver tissue samples of all the experimental groups (p < 0.001). The supplementation of broiler chickens with propolis and/or bee pollen has a strong protective effect on liver pathology in broiler chickens.

A craniometrical analysis of the Early Bronze Age dogs from Vucedol site (East Slavonia, Croatia).

During archaeological campaigne on Vucedol site 7 crania and cranial fragments together with 10 halfs of lower jaws were found. Due to existance of crania and lower jaws damages and therefore lack of preserved craniometrical points, it was not possible to measure the same craniometrical lengths on all the samples. Apart from craniometrical measurements, 6 craniometrical indices and ratios were calculated. Comparison of calculated values and values of craniometrical indices and ratios identify dog's crania from Vucedol site as dolichocephalic cranial type. Mutual comparison of all analyzed craniometrical values for crania and lower jaws of dog's crania don't show a significant difference in size and ratios of individual measures, nor significant deviation in value of the samples of other Vucedol culture sites. This point out on type of dogs with similar appearance which tallness and form respond to smaller dog's breed, in the first place a type of Croatian sheepdog or Hungarian Mudi.