MODERATE PHYSICAL ACTIVITY IMPROVES RAT BONE ULTRASTRUCTURE IN EXPERIMENTAL OSTEOPOROSIS.

CONTEXT AND OBJECTIVE: In this study, we aimed to investigate how moderate physical activity improves the bone ultrastructural parameters in rats with glucocorticoid-induced secondary osteoporosis. ANIMALS AND METHODS: Research has been carried out on Wistar female rats. Secondary osteoporosis was induced through daily i.m.1.5 mg/kgbw methylprednisolone, over a period of 30 days. A group of rats with induced secondary osteoporosis were subjected to physical activity (swimming) for one hour/day for 30 days. Rats were sacrificed 24 hours after the last administration and femoral bones were used for electron microscopy analysis. RESULTS: The ultrastructural findings obtained from the rats with osteoporosis showed varying degrees of alteration in all cellular components. A moderate physical effort led to the overall maintenance of the normal ultrastructure of the cells and connective components, protecting the lamellar structure of the compact bone from the deleterious effects of glucocorticoid. The shape and components of osteocytes were also preserved and the accumulation of lipids in the bone marrow diminished. CONCLUSIONS: Physical exercise has been shown to have a protective role by lowering the development of structural alterations specific to osteoporosis. Therefore, moderate physical exercises are recommended for improving the structure of the bone mass affected by glucocorticoid treatment.

Hepatoprotective effects of a self-micro emulsifying drug delivery system containing Silybum marianum native seed oil against experimentally induced liver injury.

The main purpose of this study was to certify the effect of native silymarin oil (SM-oil) formulated in a self-microemulsifying drug delivery system (SMEDDS). The optimal formulation was 25% of SM-oil, 33.3 % of Cremophor RH40, 20% of Transcutol HP, 16.6% of Labrasol and 5% of Capryol 90. In this novel formulation the SM-oil was the active substance and the lipid part. The in vivo study examined the preventive effects of SMEDDS containing SM native seeds oil against carbon tetrachloride (CC14) induced hepatotoxicity in mice. Determination of alanine aminotransferase (ALT), aspartate aminotransferase (AST) levels and also liver histology investigations have been done. The liver antioxidant status was determined with the concentrations of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), and glutathione (GSH) hepatic lipid peroxidation was examined and expressed in terms of malondialdehyde (MDA) content. The plasma levels of AST and ALT significantly diminished by pre-treatment with 500 mg/kg and 1000 mg/kg SMEDDS. The pre-treatment with 500 mg/kg and 1000 mg/kg SMEDDS increased GSH level by about 6% respectively 24% compared to the CC14 group. Due to preventive administration of 500 mg/kg and 1000 mg/kg of SMEDDS in the intoxicated animals, MDA levels were reduced by 22% respectively 58%. Also, an insignificant rise by almost 17% and 19% in the animals treated with the both doses of SMEDDS could be noticed. It can be concluded that hepatotoxicity may be avoided by the oral application of our formulation.

Bioinspired silk fibroin nano-delivery systems protect against 5-FU induced gastrointestinal mucositis in a mouse model and display antitumor effects on HT-29 colorectal cancer cells in vitro.

Colorectal cancer (CRC), is the second cause of cancer-related deaths worldwide is one of the most prevalent types of cancers. Conventional treatment continues to rely on surgery, chemotherapy, and radiotherapy, but for advanced cases, adjuvant chemotherapy remains the main approach for improving surgical outcomes and lower the disease recurrence probability. Chemotherapy-induced gastrointestinal (GI) toxicity is the main dose-limiting factor for many chemotherapeutic regimens, including 5-FU, and one of the biggest oncological challenges. Up to 40% of the patients receiving 5-FU get mucositis, 10-15% of which develop severe symptoms. In this context, our study aimed to develop a bioinspired nanosized drug delivery system as a strategy to reduce 5-FU associated side effects, such as GI mucositis. To this end, SF-based nanoparticles were prepared and characterized in terms of size and morphology, as well as in terms of in vitro antitumoral activity on a biomimetic colorectal cancer model by investigation of apoptosis, DNA fragmentation, and release of reactive oxygen species. Additionally, the capacity of the SF-based nanocarriers to offer intestinal protection against 5-FU-induced GI mucositis was evaluated in vivo using a mouse model that mimics the chemotherapy-associated gut mucositis occurring in colorectal cancer. Our studies show that silk fibroin nanoparticles efficiently deliver 5-FU to tumor cells in vitro while protecting against drug-induced GI mucositis in a mouse model.

Acute cardiotoxicity induced by doxorubicin in right ventricle is associated with increase of oxidative stress and apoptosis in rats.

Doxorubicin (DOX) is one of the most effective chemotherapeutic agents, but its efficiency is seriously limited by the risk of developing cardiomyopathy. The most recognized cardiotoxic effect is left ventricular (LF) dysfunction, but MRI and echocardiography data demonstrated significant right ventricle (RV) function impairment. In order to clarify this aspect, the present study investigated the potential of DOX to induce acute RV cardiotoxicity at the same time as LV impairment. Rats were intraperitoneally (i.p.) injected with a single dose of 15 mg/kg DOX. DOX-treated rats were characterized by decreased body and heart weights, elevated levels of creatine kinase (CK-MB) and lactate dehydrogenase (LDH) activities compared to controls. Biochemical analyses on RV tissue revealed that the level of malondialdehyde (MDA) was significant increased (p<0.05) and activities of catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPX) antioxidant enzymes were decreased by 13%, 27% and 18%, respectively, compared to control. Histopathogical and electron microscopic studies revealed DOX-induced damage in both ventricles and an increase of interstitial collagen fibers compared to controls (p<0.001), whereas immunohistochemical analysis showed weak and irregular desmin expression. Furthermore, mitochondrion-induced apoptotic pathways were also activated in both ventricles, as reflected by the up-regulation of Bax/Bcl-2 mRNA expression ratio (p<0.001) and increase of Bax and caspase-3 protein expression, as well as by the significant elevation of TUNEL positive nuclei, compared to controls (p<0.001). The results showed that DOX exerted RV toxic effects at the same time as those reported in the LV, which might be mediated through the mitochondrial-dependent apoptosis.

Chrysin attenuates cardiomyocyte apoptosis and loss of intermediate filaments in a mouse model of mitoxantrone cardiotoxicity.

Chrysin (CHR) is a natural flavonoid and is present in high concentration in honey, propolis and many plant extracts. The aim of the present study was to evaluate the effects of CHR to reduce cardiomyocyte apoptosis and loss of intermediate filaments in a mouse model of mitoxantrone cardiotoxicity. Morphology of the cardiomyocytes was determined by optic and transmission electron microscopy and biochemistry methods. The expression of Bcl-2, Bax and Caspase-3 were assessed by immunofluorecence. Tunel assay was used to assess apoptosis in cardiomyocytes. In addition, the distribution of desmin protein was evaluated using immunohistochemistry. Our results show that MTX treatment significantly increased serum levels of creatine kinase isoenzyme (CK-MB), indicator of cardiac injury and withdrawn under CHR protection. Expression levels of Bcl-2 decreased, while those of Bax and caspase-3 increased following MTX treatment. 50 mg/kg of daily CHR intake reduced Bax and caspase-3 immunopositivity and restored Bcl-2 levels to a value comparable to the control. TUNEL (+) cardiomyocyte nuclei of MTX group showed typical signs of apoptosis which almost completely disappeared in response to 50 mg/kg CHR treatment. In parallel, an irregular distribution and a weak expression of desmin is associated with MTX induced cardiotoxic effects which was also restored by CHR treatment. In conclusion chrysin inhibits MTX-triggered cardiomyocyte apoptosis via multiple pathways, including decrease of the Bax/Bcl-2 ratio and caspase-3 expression along with preservation of the desmin disarray.

Structural properties of silver doped hydroxyapatite and their biocompatibility.

The aim of this study was to obtain a novel hydroxyapatite-based material with high biocompatibility. The structural properties of the samples were well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). The X-ray diffraction studies revealed the characteristic peaks of hydroxyapatite in each sample. Other phases or impurities were not observed. The scanning electron microscopy observations suggest that the doping components have no influence on the surface morphology of the samples, which reveals a homogeneous aspect of the synthesized particles for all samples. The presence of calcium (Ca), phosphor (P), oxygen (O) and silver (Ag) in the Ag:HAp is confirmed by energy dispersive X-ray (EDAX) and X-ray Photoelectron Spectroscopy analyses. Nanocrystalline silver doped HAp stimulated viability and potentiated the activation of murine macrophages.