The results in our study appear to establish the osteoporosis model and provide evidence of the positive effects of three separate PDE5 inhibitors (vardenafil, udenafil, and tadalafil). The positive effects of these PDE5 inhibitors are investigated and demonstrated by the bone mass density and bone resorption markers. These effects are associated with significant demonstrated antioxidant activities. Osteoporosis is a significant major public health problem especially in more aged populations. Advances in identifying and understanding new potential therapeutic modalities for this disease are significant. This study provides such an advance. AbstractOsteoporosis is a major public health problem associated with many factors, and it affects more than 50% of women over 50 years old. In the current study, our purpose was to investigate the effects of phosphodiestarase-5 inhibitors on osteoporosis via the nitric oxide/3 0 ,5 0 -cyclic guanosine monophosphate/protein kinase G signalling pathway. A total of 50 female albino Wistar rats were separated into five groups. The first group was appointed as the healthy control group with no ovariectomy. All animals in the other groups underwent a bilateral ovariectomy. Six months after the ovariectomy, vardenafil, udenafil and tadalafil were given to the third, fourth and fifth groups, respectively, but were not administered to the positive control group (10 mg/kg per day for two months). The bone mineral density values were determined using a densitometry apparatus for all groups pre-and post-ovariectomy as well as after treatment. The levels of nitric oxide, endothelial nitric oxidesynthase, asymmetric dimethylarginine, 3 0 ,5 0 -cyclic guanosine monophosphate, protein kinase G, phosphodiestarase-5, pyridinoline, deoxypyridinoline, carboxyterminal telopeptide fragments and plasma carboxy terminal propeptide of type I collagen were determined using an enzyme linked immunosorbent assay. The levels of malondialdehyde, 8-hydroxy-2-deoxy guanosine, deoxyguanosine and coenzyme Q10 were determined by a high-performance liquid chromatography assay. Additionally, the right femoral trabecular bone density and the epiphyseal plate were measured in all groups. Angiogenesis was histologically observed in the bone tissue. In addition, we determined that the inhibitors may have caused a positive impact on the increased bone mass density and reduction of bone resorption markers. We also observed the positive effects of these inhibitors on oxidative stress. In conclusion, these phosphodiestarase-5 inhibitors increase angiogenesis in bone tissue and improve the re-formation rate of bone in rats with osteoporosis.

This study aimed to investigate the possible protective effect of paricalcitol on experimental amikacin-induced nephrotoxicity model in rats. Wistar albino rats (n ¼ 32) were allocated into four equal groups of eight each, the control (Group C), paricalcitol (Group P), amikacin-induced nephrotoxicity (Group A), and paricalcitol-treated amikacin-induced nephrotoxicity (Group A þ P) groups. Paricalcitol was given intra-peritoneally at a dose of 0.4 lg/kg/d for 5 consecutive days prior to induction of amikacin-induced nephrotoxicity. Intra-peritoneal amikacin (1.2 g/kg) was used to induce nephrotoxicity at day 4. Renal function parameters, oxidative stress biomarkers, oxidative DNA damage (8-hydroxy-2 0 -deoxyguanosine/deoxyguanosine ratio), kidney histology, and vascular endothelial growth factor (VEGF) immunoexpression were determined. Group A þ P had lower mean fractional sodium excretion (p < 0.001) as well as higher creatinine clearance (p ¼ 0.026) than the amikacin group (Group A). Renal tissue malondialdehyde levels (p ¼ 0.035) and serum 8-hydroxy-2 0 -deoxyguanosine/deoxyguanosine ratio (8-OHdG/dG ratio) (p < 0.001) were significantly lower; superoxide dismutase (p ¼ 0.024) and glutathione peroxidase (p ¼ 0.007) activities of renal tissue were significantly higher in group A þ P than in group A. The mean scores of tubular necrosis (p ¼ 0.024), proteinaceous casts (p ¼ 0.038), medullary congestion (p ¼ 0.035), and VEGF immunoexpression (p ¼ 0.018) were also lower in group A þ P when compared with group A. This study demonstrates the protective effect of paricalcitol in the prevention of amikacin-induced nephrotoxicity in an experimental model. Furthermore, it is the first study to demonstrate that paricalcitol improves oxidative DNA damage in an experimental acute kidney injury model. ARTICLE HISTORY

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In this investigation, the effect of steaming on the water vapor diffusion coefficient of poplar wood (Populus nigra L.) was studied. Boards with dimensions of 50 × 50 × 150 (W × H × L) mm 3 and average moisture content of 12% were steamed at temperatures of 120, 140, 160, and 180 °C for 1, 2, and 3 h. The diffusion coefficients were then measured based on Fick's law of diffusion in steadystate conditions using the cup method. Results showed that the steaming of poplar wood at all mentioned temperatures can decrease the water vapor diffusion coefficient. However, no further improving effect was caused by increasing the steam temperature or duration. Some significant wood anatomical and chemical changes like cell wall collapse and holocellulose hydrolysis give some explanations for the improving effect of steaming on the diffusion coefficient. Overall, steaming at temperature of 120 °C for 1 h as the best treatment is recommended to modify the water vapor diffusion coefficient.

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