Cadmium chloride toxicity suppresses osteogenic potential of rat bone marrow mesenchymal stem cells through reducing cell viability and bone matrix mineralization.

Background and Objectives: Cadmium an environmental pollutant, exert several risks to human health. In this study we investigated the effect of cadmium chloride (CdCl 2 ) on Viability, morphology and bone Matrix Miniralization of Rat Bone Marrow Mesenchymal Stem Cells (rMSCs). Materials and Methods: rMSCs were cultured in DMEM containing 15% FBS and pen-strep. After 21 days of treatment with the selected doses of 750 and 2000 nM of CdCl 2 viability, colony forming unit, population doubling number, DAN breakage and the morphology of the cells were studied. Also to study the effects of CdCl2 on differentiation property, the morphology and bone matrix mineralization via estimation of intracellular calcium concentration and quantitative alizarin red were also evaluated in the cells using Hoechst, Acridine orange and Alizarin red staining. Data was analyzed using one-way ANOVA and Tukey ' s test and the means difference was considered significant at P<0.05. Results: The mean viability, colony forming unit, population doubling number and also the mean bone matrix mineralization of the rMSCs treated with CdCl 2 significantly reduced in a dose dependent manner. Nuclear fragmentation and cytoplasm shrinkage was also seen in the treated cells. Conclusion: CdCl 2 can reduce the viability and bone matrix mineralization of rMSCs even at low doses.

Histological and radiographic evaluation of the muscle tissue of rats after implantation of bone morphogenic protein (rhBMP-2) in a scaffold of inorganic bone and after stimulation with low-power laser light.

Objective: The present study histologically and radiologically evaluates the muscle tissue of rats after implantation of bone morphogenic protein (rhBMP-2) in a natural inorganic bone mineral scaffold from a bull calf femur and irradiation with low-power light laser. Materials and Methods: The right and left hind limbs of 16 rats were shaved and an incision was made in the muscle on the face corresponding to the median portion of the tibia, into which rhBMP-2 in a scaffold of inorganic bone was implanted. Two groups of limbs were formed: control (G1) and laser irradiation (G2). G2 received diode laser light applied in the direction of the implant, at a dose of 8 J/cm2 for three minutes. On the 7th, 21st, 40th and 112th days after implantation, hind limbs of 4 animals were radiographed and their implants removed together with the surrounding tissue for study under the microscope. The histological results were graded as 0=absence, 1=slight presence, 2=representative and 3=very representative, with regard to the following events: formation of osteoid structure, acute inflammation, chronic inflammation, fibrin deposition, neovascularization, foreign-body granuloma and fibrosis. Results: There were no statistically significant differences in these events at each evaluation times, between the two groups (P>0.05; Mann-Whitney test). Nevertheless, it could be concluded that the natural inorganic bone matrix with rhBMP-2, from the femur of a bull calf, is a biocompatible combination. Conclusions: Under these conditions, the inductive capacity of rhBMP-2 for cell differentiation was inhibited. There was a slight acceleration in tissue healing in the group that received irradiation with low-power laser light.

Comparative study of cryopreserved bone tissue and tissue preserved in a 98 percent glycerol solution / Estudo comparativo entre o tecido ósseo criopreservado e o conservado em glicerol a 98 por cento

OBJECTIVE: To compare the bone graft cryopreservation method (at -80°C) with a preservation method using a 98 percent glycerol solution at room temperature (10°C-35°C), by testing the antibacterial and fungal effects of 98 percent glycerol and comparatively analyzing the observed histological changes resulting from the use of both methods. METHOD: This study was of 30 samples of trabecular bone tissue from 10 patients undergoing total hip arthroplasty. Each femoral head provided 3 samples that were randomized into 3 groups, namely, the control group, the cryopreserved group, and the group preserved in a 98 percent glycerol at room temperature for 1 year. The samples were submitted to histomorphologic, cell feasibility, and microbiologic analyses. The results were statistically analyzed using the McNemar test, with a statistical significance index of 0.05. RESULTS: Values obtained using the McNemar test to compare probability distributions of histomorphologic variables (mature or lamellar bone, immature bone, and necrosis) and cell feasibility (osteoblasts and osteoclasts) indicated that there is no difference between the distributions of variables under the 3 experimental conditions. Microbiological analysis of the 98 percent glycerol solution and bone fragments from samples stored for 1 year at room temperature did not show bacterial or fungal growth. The histological and microbiological investigation were performed at 2 different time points: immediately after the sample processing and after 1 year. CONCLUSION: The method used to preserve bone grafts kept in 98 percent glycerol at room temperature (10°C-35°C) was similar to cryopreservation in terms of bone matrix preservation; no bacteria or fungi were found in the samples.

OBJETIVO: Comparar o método da criopreservação de enxertos ósseos (- 80° C) com o da conservação em glicerol a 98 por cento em temperatura ambiente (10° C a 35° C), testando os efeitos antibacterianos e antifúngicos do glicerol a 98 por cento e analisando comparativamente as alterações histológicas verificadas e decorrentes do emprego dos dois métodos. MÉTODO: Este estudo foi constituído de 30 amostras de tecido ósseo trabecular provenientes de 10 pacientes, submetidos a Artroplastia Total do Quadril. Cada cabeça femoral forneceu 3 amostras e estas foram divididas aleatoriamente em 3 grupos, a saber: controle, criopreservado e conservado em glicerol a 98 por cento à temperatura ambiente durante um ano. As amostras foram encaminhadas à Anatomia Patológica para estudo histomorfologico, de viabilidade celular, e microbiológico. Os resultados foram analisados estatisticamente pelo método de McNemar, com índice de significância de 0,05. RESULTADOS: A análise dos valores obtidos no teste de McNemar na comparação das distribuições de probabilidades das variáveis da histomorfologia (osso maduro ou lamelar, osso imaturo e necrose) e da viabilidade celular (osteoblastos e osteoclastos) indica não haver diferença entre as distribuições das variáveis nas três condições experimentais. A análise microbiológica da solução de glicerol a 98 por cento e dos fragmentos ósseos das amostras armazenadas durante um ano em temperatura ambiente não apresentou crescimento bacteriano ou de fungos. As espécimens do grupo controle foram analisadas histológica e microbiologicamente logo após a coleta das mesmas. CONCLUSÃO: O método de conservação de enxertos ósseos mantidos no glicerol a 98 por cento em temperatura ambiente (10°C a 35°C) foi similar ao da criopreservação quanto à preservação da matriz óssea e à ausência de crescimento de bactérias ou fungos.

Alteraciones en la matriz organica del hueso y cartilago de rata por el uso prolongado de fluoruno de sodio / Alterations in the organic matrix of bone and cartilage after prolonged administration of sodium fluoride in the rat

Los fluoruros, por mecanismos aun no aclarados, estimulan la formación ósea y son, en consecuencia, usados en el tratamiento de las osteoporosis. Desde un punto de vista terapéutico, uno de los efectos más esperados por la ingesta de fluoruro en pacientes osteoporóticos es la disminución en el índice de fracturas. Si bien esto ocurre, observaciones clínicas sugieren que este efecto es menor que el esperado por el aumento de la masa ósea (ej.: la resistencia por unidad de tejido estaría disminuida en el hueso fluorótico). El o los mecanismos por los cuales el fluoruro conduce a las alteraciones mencionadas, todavía no son bien conocidos, pero como el componente inorgánico ha sido extensamente estudiado, hemos llevado a cabo este trabajo con el objeto de caracterizar cuali y cuantitativamente a los GAG y el colágeno de hueso y cartílafo de rata, en función de la ingesta prolongada de fluoruro de sodio. Las variaciones producidas por la ingesta de fluoruro implican un aumento significativo en la concentracicón de GAG, después de dos meses de tratamiento, debidas a un incremento en las fracciones correspondentes al condroitín-6-sulfato y dermatán sulfato. Esta modificación en el patrón de distribución de los GAG no es atribuible a variaciones en el peso de las moléculas. Aunque otros estudios han informado que no se observan efectos sobre la síntesis de colágeno o de DNA, como consecuencia de la ingesta de fluoruro, nuestros resultados muestran que el contenido de OH-Pro se halla aumentado significativamente luego de 2 meses de tratamiento. Los datos presentados sugieren que las alteraciones óseas inducidas por el fluoruro, podrían se, al menos en parte, debidas a cambios en la concentración y distribución de los GAG y el colágeno en la matriz calcificable de hueso y cartílago de rata