Roberto Lopes de Souza

Osteocytes Use Estrogen Receptor α to Respond to Strain but Their ERα Content Is Regulated by Estrogen

The role of mechanical strain and estrogen status in regulating ERα levels in bone cells was studied in female rats. OVX is associated with decreased ERα protein expression/osteocyte, whereas habitual strain and artificial loading has only a small but positive effect, except on the ulnas medial surface, where artificial loading stimulates reversal of resorption to formation.

Sympathetic nervous system does not mediate the load-induced cortical new bone formation

The contribution of the SNS to bones response to mechanical loading is unclear. Using a noninvasive model of axial loading of the murine tibia, we found that sciatic neurectomy enhances load‐induced new cortical bone formation and that pharmacological blockade of the SNS does not affect such responses, indicating that the SNS does not mediate the osteogenic effects of loading in cortical bone.

Conidiobolomicose em ovinos no Estado de Mato Grosso

The epidemiological, clinical, pathological and mycological findings of an outbreak of conidiobolomycosis in a flock of 40 Santa Ines sheep, in the state of Mato Grosso, Brazil, are reported. The illness occurred in the municipality of Nobres during January-June, 2007, resulting in death of about 30% of the affected sheep within 2-5 weeks. The clinical signs were characterized by apathy, weight loss, labored and noisy breathing with dyspnea, and mucous or serohemorrhagic nasal discharge. In three sheep there was unilateral exophthalmia, keratitis and corneal ulceration. A firm whitish, multi-lobulated, friable growth was evident in the ethmoturbinate region at the coronal sections of the head from six affected sheep. In all sheep the choana had similar nodular infiltration which resulted in local obstruction. In three of those there was exophthalmia. There was infiltration in the cribiform plate and brain (2 cases), regional lymph nodes (2), lungs (3), and abomasums (1). Microscopic findings were granulomatous inflammation of the rhinoetimoidal region, with necrosis, lymphocytic infiltration, epithelioid multinucleated giant cells and fibrovascular tissue, surrounding Splendore-Hoeppli material wich contained unstained ghost images of hyphae. The methenamine-silver stain uncover fungi hyphae, rarely ramified with bulbous dilatation in their extremities. Conidiobolus sp. was isolated from nasal tissue lesions of four sheep.

Leishmania (Leishmania) chagasi in captive wild felids in Brazil

This study used a PCR-RFLP test to determine the presence of Leishmania (Leishmania) chagasi in 16 captive wild felids [seven Puma concolor (Linnaeus, 1771); five Panthera onca (Linnaeus, 1758) and four Leopardus pardalis (Linnaeus, 1758)] at the zoological park of the Federal University of Mato Grosso, Brazil. Amplification of Leishmania spp. DNA was seen in samples from five pumas and one jaguar, and the species was characterized as L. chagasi using restriction enzymes. It is already known that domestic felids can act as a reservoir of L. chagasi in endemic areas, and further studies are necessary to investigate their participation in the epidemiological chain of leishmaniasis.

Modifications of Gait as Predictors of Natural Osteoarthritis Progression in STR/Ort Mice

Osteoarthritis (OA) is a common chronic disease for which disease‐modifying therapies are not currently available. Studies to seek new targets for slowing the progress of OA rely on mouse models, but these do not allow for longitudinal monitoring of disease development. This study was undertaken to determine whether gait can be used to measure disease severity in the STR/Ort mouse model of spontaneous OA and whether gait changes are related to OA joint pain.

The first case report of Leishmania (leishmania) chagasi in Panthera leo in Brazil.

We reported here the first known case of natural infection of a lion (Panthera leo-Linnaeus, 1758) with Leishmania (Leishmania) chagasi (L. chagasi) in Brazil. The specimen was created by a circus handler in the state of Mato Grosso and was donated to the zoological park of the Federal University of Mato Grosso. Infection by L. chagasi was detected using a PCR-RFLP test. It was known that the domestic felids can act as reservoir of infection of L. chagasi in endemic areas, making it important that studies demonstrate their participation in the epidemiological chain. We demonstrate in this work that wild animals can have an important role in the epidemiological chain and must be considered in order to plan methods of control of this zoonosis.

Hydroethanolic extract of the inner stem bark of Cedrela odorata has low toxicity and reduces hyperglycemia induced by an overload of sucrose and glucose

ETHNOPHARMACOLOGICAL RELEVANCE Cedrela odorata L. (Meliaceae) is a native plant of the Amazon region and its inner stem bark is used in the treatment of diabetes in the form of maceration in Brazilian popular medicine. Until now, there is no scientific study on this activity. The present study was aimed at evaluating the anti-hyperglycemic activity, anti-diabetic, toxicity, antioxidant and potential mechanism of action of hydroethanolic extract of the inner stem bark of Cedrela odorata. MATERIAL AND METHODS The inner stem bark extract of Cedrela odorata was prepared by maceration in 70% ethanol for 7 days to obtain hydroethanolic extract of Cedrela odorata (HeECo). The preliminary phytochemical analysis was performed according to procedures described in the literature. Selected secondary metabolites detected were quantified by high performance liquid chromatography (HPLC). Acute toxicity of HeECo was investigated in male and female mice with oral administration of graded doses of HeECo from 10 to 5000 mg/kg. Subchronic oral toxicity study was done by oral administration of HeECo (500 mg/kg) and vehicle for 30 days to both sexes of Wistar rats. Clinical observations and toxicological related parameters were determined. Blood was collected for biochemical and hematological analyses, while histological examinations were performed on selected organs. Anti-hiperglycemic and antidiabetic effects were evaluated in streptozotocin-induced diabetic rats. In acute evaluation, the animals received pretreatment with 250 and 500 mg/kg of HeECo, before carbohydrate overload. For subchronic effect, the antidiabetic activity of HeECo was evaluated using the same doses for 21 days. At the end of the treatments, the levels of triacylglycerols, malondialdehyde, total antioxidant status, superoxide dismutase and glutathione peroxidase activities were evaluated in the plasma. RESULTS The extract showed low acute toxicity. HeECo exhibited inhibitory activity against α-glucosidase and caused a lowering in the peak levels of blood glucose in animals that received glucose overload by 36.7% and 24.1% in the area under the glucose curve (AUC). When the overload was sucrose, HeECo reduced the blood glucose level by 44.4% without affecting AUC. Treatment with HeECo of the blood glucose of the diabetic animals for 21 days did not lead to improvement in weight gain and regularization of the blood glucose level, but reduced the triacylglycerol and malondialdehyde levels by 36.6% and 48.1%, respectively. The activity of the antioxidant enzymes, superoxide dismutase and glutathione peroxidase were significantly increased when compared to diabetic control rats. HPLC analysis showed the presence of polyphenols, such as gallic acid, (-)- gallocatechin and (+)- catechin, the latter is present in higher quantity. CONCLUSIONS Collectively, these data showed that HeECo could blunt the postprandial glycemic surge in rats; possibly through inhibition of alpha-glucosidase and positive modulation of antioxidant enzymes. Our findings confirmed the anti-hiperglycemic activity of HeECo in STZ- diabetic rats. Cedrela odorata is effective in diminishing glucose levels in vitro and in vivo and in ameliorating oxidative damage that occurs in diabetes and/or due to hyperglycemia in rats. According to our results, the efficacy of Cedrela odorata preparation could be due to the presence of active principles with different mode of actions at the molecular level, including α-glycosidases and glucose transporter inhibitors and antioxidant property.

Stable sulforaphane protects against gait anomalies and modifies bone microarchitecture in the spontaneous STR/Ort model of osteoarthritis

Osteoarthritis (OA), affecting joints and bone, causes physical gait disability with huge socio-economic burden; treatment remains palliative. Roles for antioxidants in protecting against such chronic disorders have been examined previously. Sulforaphane is a naturally occurring antioxidant. Herein, we explore whether SFX-01®, a stable synthetic form of sulforaphane, modifies gait, bone architecture and slows/reverses articular cartilage destruction in a spontaneous OA model in STR/Ort mice. Sixteen mice (n = 8/group) were orally treated for 3 months with either 100 mg/kg SFX-01® or vehicle. Gait was recorded, tibiae were microCT scanned and analysed. OA lesion severity was graded histologically. The effect of SFX-01® on bone turnover markers in vivo was complemented by in vitro bone formation and resorption assays. Analysis revealed development of OA-related gait asymmetry in vehicle-treated STR/Ort mice, which did not emerge in SFX-01®-treated mice. We found significant improvements in trabecular and cortical bone. Despite these marked improvements, we found that histologically-graded OA severity in articular cartilage was unmodified in treated mice. These changes are also reflected in anabolic and anti-catabolic actions of SFX-01® treatment as reflected by alteration in serum markers as well as changes in primary osteoblast and osteoclast-like cells in vitro. We report that SFX-01® improves bone microarchitecture in vivo, produces corresponding changes in bone cell behaviour in vitro and leads to greater symmetry in gait, without marked effects on cartilage lesion severity in STR/Ort osteoarthritic mice. Our findings support both osteotrophic roles and novel beneficial gait effects for SFX-01® in this model of spontaneous OA.

Transient peak-strain matching partially recovers the age-impaired mechanoadaptive cortical bone response

Mechanoadaptation maintains bone mass and architecture; its failure underlies age-related decline in bone strength. It is unclear whether this is due to failure of osteocytes to sense strain, osteoblasts to form bone or insufficient mechanical stimulus. Mechanoadaptation can be restored to aged bone by surgical neurectomy, suggesting that changes in loading history can rescue mechanoadaptation. We use non-biased, whole-bone tibial analyses, along with characterisation of surface strains and ensuing mechanoadaptive responses in mice at a range of ages, to explore whether sufficient load magnitude can activate mechanoadaptation in aged bone. We find that younger mice adapt when imposed strains are lower than in mature and aged bone. Intriguingly, imposition of short-term, high magnitude loading effectively primes cortical but not trabecular bone of aged mice to respond. This response was regionally-matched to highest strains measured by digital image correlation and to osteocytic mechanoactivation. These data indicate that aged bone’s loading response can be partially recovered, non-invasively by transient, focal high strain regions. Our results indicate that old murine bone does respond to load when the loading is of sufficient magnitude, and bones’ age-related adaptation failure may be due to insufficient mechanical stimulus to trigger mechanoadaptation.

In Vivo Mechanical Loading

The skeleton fulfils its mechanical functions through structural organisation and material properties of individual bones. Both cortical and trabecular morphology and mass can be (re)modelled in response to changes in mechanical strains engendered by load-bearing. To address this, animal models that enable the application of specific loads to individual bones have been developed. These are useful in defining how loading modulates (re)modelling and allow examination of the mechanisms that coordinate these events. This chapter describes how to apply mechanical loading to murine bones through points of articulation, which allows changes in endosteal, periosteal as well as trabecular bone to be revealed by double fluorochrome labelling and computed tomography, respectively.