Cytotoxic effects of Euterpe oleraceae fruit oil (açaí) in rat liver and thyroid tissues

Abstract Euterpe oleracea Mart., Arecaceae, fruit (açaí) presents considerable potential for the development of new medicines due to its phytochemical composition and antioxidant activity. More recently, special attention has been given to the pharmacological potential of the fruit's oil. This study analysed the histological and histochemical effects of different dosages of açaí oil on rat's liver and thyroid cells, in order to evaluate its cytotoxic potential after administration for consecutive days. Male Wistar rats were treated with the açaí oil by gavage at doses of 30, 100 and 300 mg/kg, for 14 days, within a 24 h interval. Liver and thyroid fragments were collected for histology (hematoxylin and eosin) and histochemistry analysis (blue of Nilo (lipids), Baker (lipids), bromophenol blue (protein), PAS (polysaccharides)). The results showed that animals exposed to açaí oil presented alterations in the liver cells, where the integrity of the liver tissue was increasingly lost as the açaí oil doses increased. Nuclear pyknosis was observed in several hepatocytes, evidencing the occurrence of cell death. Alteration in the amount of lipids, polysaccharides, vacuoles in the cytoplasm, and proliferation of Kupffer cells were observed in histochemical analyzes. As for the thyroid of the treated rats, alterations were observed in the size of the follicular lumen and also in the connective tissue found between the follicles. Under the experimental conditions employed in the present study, the cytotoxicity observed in this work is worrying, specially considering the liver, when frequent or continuous damage could lead pathological disorders in this organ.

In vivo study of a homeopathic medicine against Rhipicephalus (Boophilus) microplus in dairy cow

ABSTRACT The tick Rhipicephalus (Boophilus) microplus (Canestrini, 1887) (Acari: Ixodidae) causes large economic losses to cattle breeders and its control is hampered by problems of resistance to the main commercial synthetic acaricides and the risk of residues in animal products. Alternative controls are important for the sustainability of cattle breeding in tropical regions, principally for organic milk production. This study evaluated the efficacy of a homeopathic preparation to control natural tick infestations. The evaluations were conducted with 24 taurine dairy cows during 12 months. The homeopathic medicine (30 CH + Sulfur 30 CH) was administered in a proportion of 1:100 (v/w) in a formulation with sugar, added to 30 kg of mineral salt. This preparation was supplied along with concentrated feed (2 kg/animal/day). The control group received the same feed mixture without the medicine. The groups were kept in separate paddocks. Data were collected on body weight, packed cell volume and number of engorged female ticks on each animal. Temperature, relative humidity and rainfall were recorded. Engorged females were collected from each group for in vitro comparison of reproductive parameters, and semi-engorged ticks for morpho-histological analysis. The mean results of body weight, packed cell volume and tick number were not statistically different between the control and treated groups: 616.5 kg and 618.6 kg; 27.9% and 27.3%; and 12.19 and 13.58 ticks, respectively. In the in vitro analyses, the average weights of the ticks (0.18 and 0.17 g) and eggs (0.07 and 0.06 g), larval hatching rate (70.1 and 76.6%) and reproductive efficiency index (54.3 and 60.6%) of the control and treated groups, respectively, also were not statistically different. Furthermore, no alteration in the ovaries was detected by microscopic analysis. Therefore, the homeopathic medicine was ineffective to control R. (B.) microplus, although the inclusion of agro-ecological practices might enhance its effect of homeopathy in controlling tick infestations.

Ticks infesting birds in Atlantic Forest fragments in Rio Claro, State of São Paulo, Brazil / Carrapatos infestando aves em fragmentos de Mata Atlântica em Rio Claro, São Paulo, Brasil

In the present study, we report tick infestations on wild birds in plots of the Atlantic Forest reforested fragments with native species and plots reforested with Eucalyptus tereticornis in the municipality of Rio Claro, State of São Paulo, Brazil. A total of 256 birds were captured: 137 individuals of 33 species, in planted native forest; and 128 individuals of 37 species, in planted Eucalyptus tereticornis forest. Nymphs of two tick species were found on the birds: Amblyomma calcaratum and Amblyomma longirostre, the former was more abundant in the fragments reforested with Atlantic forest native species, and the latter in the fragment reforested with E. tereticornis. New host records were presented for A. calcaratum.

O presente estudo apresenta infestações de carrapatos em aves silvestres em fragmentos de reflorestamento com espécies nativas e fragmentos de reflorestamento com Eucalyptus tereticornis no município de Rio Claro, São Paulo. No total foram capturadas 265 aves, sendo 137 indivíduos de 33 espécies nas áreas de reflorestamento com espécies nativas e 128 indivíduos de 37 espécies nas áreas reflorestadas com Eucalyptus tereticornis. Ninfas de duas espécies de carrapatos foram registradas: Amblyomma calcaratum e Amblyomma longirostre, sendo a primeira mais abundante na área nativa e a segunda na área de Eucalyptus tereticornis. Novos registros de hospedeiros para A. calcaratum são apresentados.

Mineralized bodies in the fat body of rhinocricus padbergi (Diplopoda)

The fat body is a loosely packed tissue distributed throughout the body cavities of millipedes. The mainfunction of this tissue is the storage of lipids, glycogen, proteins and uric acid and also serves as a site forthe permanent storage for excretion products. In this work, we examined the ultrastructure of the mineralizedbodies found in the fat body of the millipede Rhinocricus padbergi. The mineralized bodies were sphericalbodies that varied in structural organization within a single cell: some consisted of several concentric layers ofamorphous material while others were surrounded by a layer of electron-dense material intimately associatedwith the surrounding membrane. The histochemical and ultrastructural results suggested that these mineralizedbodies are involved in the accumulation of calcium and uric acid. The large number of these structures foundin the fat body of millipedes may be a consequence of these animals´ diet since they overturn soil rich in largeamounts and/or variety of minerals. As in other organisms, uric acid probably accumulates as the metabolicproduct of the degradation of nucleic acids derived from autophagy of the rough endoplasmic reticulum duean earlier massive protein synthesis, but may also be extracted from the hemolymph.

Ultrastructural features of the midgut of Rhinocricus padbergi (Diplopoda: spiroboida)

The midgut epithelium of the milipede Rhinocricus padbergi has been reported to be stratified or pseudostratified, and there is evidence that this region of the intestine is lined by a single layer of absorptive epithelial cells interspersed with smaller regenerative cells. In this work, transmission electron microscopy was used to study the structure and organization of the midgut of R. padbergi. The midgut was lined by a pseudostratified epithelium in which all of the cells were in contact with the basement membrane but did not necessarily reach the apical surface. The epithelium contained three cells types, namely, absorptive cells with apical microvilli that gave the midgut epithelium a "brush border" appearance, secretory cells that were interspersed with the absorptive cells and probably served to lubricate the epithelial surface, and regenerative cells located in the basal region of the epithelium. This organization of the gut cells in R. padbergi was similar to that of other arthropodes.

External morphology of the antennae of Rhinocricus padbergi Verhoeff, 1938 (Diploda, Spirobolida)

The antennae of millipedes (Diplopoda) have an important role in detecting various types of enviromental stimuli. The structural organization of the antennae is closely related to the degree of sensorial perception. The antennae generally consist of eight segments, the most distal (apical) of which characteristically contains four cone-shaped sensilla. In this paper, we describe the external morphology of the antennae of the diplod Rhinocricus padbergi. Antennae from anesthetized mael and female millipedes were fixed in Karnovsky solution and processed for scanning electron microscopy. Intraspecific variation was observed in the number of apical cones (13-18) in segment VIII. This number of cones differed from that usually found (4) in other millipedes species. Segments I, II and III lacked sensilla while the remaining segments had different types of sensilla, including trichoidea, chaetica and basiconica. The presence of the latter types of sensilla suggests that R. padbergiantennae have chemoreceptor, mechanoreceptor and thermal/ hygrosensitive functions, respectively.

Ultrastructural features of the fat body and oenocytes of Rhinocricus padbergi Verhoeff (Diplopoda, Spirobolida)

The fat body of the diplopod Rhinocricus padbergi is located in two preferential areas of its body: a) immediately below the tegument, denominated parietal, and b) filling the body cavity, close to the viscera, mainly the ovaries and alimentary canal, denominated perivisceral. Ultrastructurally, its cells, the adipocytes, presented varied morphology and contained organelles indicating that they are cells that mainly produce and store lipids and proteins. The presence of cells similar to the oenocytes found in insects was observed for the first time in diplopods, associated to the fat body of R. padbergi. Our observations suggest that this tissue probably maintains activity cycles, since the presence of cells undergoing apoptosis was detected.