Nitric oxide metabolite levels during the ectopic osteoinduction in rats

Abstract Nitric oxide (NO) is a cell-signaling molecule that has diverse biological functions. Recent evidence suggests that its production may regulate the metabolism of the osteoblasts and osteoclasts. The aim of this study was to evaluate levels of nitrite and nitrates (NO metabolites) during ectopic osteoinduction in rats. Eighteen male Sprague–Dawley rats (body weight 200–300 g) were used in this study. All animals were anesthetized and the right and left flank areas were shaved, and under aseptic conditions, a muscular pouch was created in each flank: the left was filled with 20 mg of demineralized bone matrix and the right remained empty (sham). Radiographs were taken at 2, 4, and 6 weeks after surgery to trace the ectopic bone formation and muscle mineralization. Blood samples were taken before (as baseline values) and at 2, 4, and 6 weeks after surgery. The mean values of NO metabolites after 6 weeks were significantly higher (p<0.05) than baseline data and at 2 weeks post-surgery. Results from this study indicate that the ectopic osteoinduction caused increased activity of the osteoblasts which subsequently caused increased serum levels of NO metabolites (nitrites and nitrates)

Accurate automated quantitative imaging of tortoise erythrocytes using the NIS image analysis system

The standard method for assessing blood cell characteristics using an ocular micrometer is time-consuming and limited. We used the Nikon NIS Elements imaging software and May-Grünwald-Giemsa staining to determine whether automated image analysis is suitable for rapid and accurate quantitative morphometry of erythrocytes. Blood was collected during four seasons from 126 geometric tortoises and the blood smears were evaluated for cell (C) and nuclear (N) characteristics of the erythrocytes. We measured area, length (L), width (W), perimeter, elongation and pixelation intensity, and calculated L/W and N/C areas. Erythrocyte size differed among cohorts; females, the larger sex, had smaller erythrocytes than either males or juveniles. Males had more elongated erythrocytes than females and erythrocytes of adults were more elongated than those of juveniles. Erythrocyte size and shape influence the efficiency of gas exchange owing to surface area to volume ratios, which are greater for small, elongated cells than for large, round cells. The high N/C ratio and low pixelation intensities of males and juveniles indicate that they may have had more immature erythrocytes in their circulation than females. The use of pixelation intensity to indicate the presence of immature erythrocytes was validated by seasonal differences that corresponded to the biology of the tortoises. Pixelation intensity was lowest in winter. We found that automated image analysis is a rapid and reliable method for determining cell size and shape, and it offers the potential for distinguishing among developmental stages that differ in staining intensity. The method should be useful for rapid health assessments, particularly of threatened species, and for comparative studies among different vertebrates.Web of Scienc

Evaluation of the effects of chitosan nanoparticles on polyhydroxy butyrate electrospun scaffolds for cartilage tissue engineering applications

In this study, we synthesized and incorporated chitosan nanoparticles (Cs) into polyhydroxy butyrate (PHB) electrospun scaffolds for cartilage tissue engineering. The Cs nanoparticles were synthesized via an ionic gel interaction between Cs powder and tripolyphosphate (TPP). The mechanical properties, hydrophilicity, and fiber diameter of the PHB scaffolds with varying concentrations of Cs nanoparticles (1-5 wt) were evaluated. The results of these evaluations showed that the scaffold containing 1 wt Cs nanoparticles (P-1Cs) was the optimum scaffold, with increased ultimate strength from 2.6 to 5.2 MPa and elongation at break from 5.31 to 12.6 . Crystallinity, degradation, and cell compatibility were also evaluated. The addition of Cs nanoparticles decreased crystallinity and accelerated hydrolytic degradation. MTT assay results showed that the proliferation of chondrocytes on the scaffold containing 1 wt Cs nanoparticles were significantly higher than that on pure PHB after 7 days of cultivation. These findings suggest that the electrospun P-1Cs scaffold has promising potential as a substrate for cartilage tissue engineering applications. This combination offers a promising approach for the fabrication of biomimetic scaffolds with enhanced mechanical properties, hydrophilicity, and cell compatibility for tissue engineering applications

Evaluation of the Effects of Decellularized Wharton Jelly Nanoparticles on Polyhydroxy Butyrate-Chitosan Electrospun Scaffolds for Cartilage Tissue Engineering Applications

An integral part of cartilage tissue engineering is scaffold fabrication methods and the selection of materials that mimic the extracellular matrix of the host tissue. This study aims to investigate the effects of the decellularized extracellular matrix of cord Wharton’s jelly (DWJM) on polyhydroxybutyrate (PHB)-nano chitosan (Cs) electrospun scaffold by adding (0.1, 0.2, and 0.3) wt of DWJM nanoparticles. Evaluation of the results regarding fiber diameter, hydrophilicity, and mechanical properties confirmed that the scaffold with 0.2 wt DWJM nanoparticles is the optimal choice. The average fiber diameter decreased from 441.5 to 327.4 nm, while the ultimate strength increased from 5.1 to 7.5 MPa, and the elongation at break increased from 11.9 to 13.7. The addition of DWJM nanoparticles played a significant role in reducing crystallinity, increasing hydrolytic decomposition, appropriate degradation, and enhancing cell compatibility. Based on the results of the MTT test, a significant increase in the growth and proliferation of chondrocytes on the scaffolds with 0.2 wt DWJM nanoparticles was observed compared to the PHB-Cs scaffold during 7 days of cell culture. In conclusion, the nanocomposite scaffold containing of 0.2 wt DWJM nanoparticles exhibits efficient biological behavior and can serve as a suitable option for cartilage tissue engineering. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024