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Tissue engineering is based on three main factors including scaffolds, cells and growth factors. Natural scaffolds derived from decellularized tissues and organs have been successfully used in tissue engineering. Decellularization studies have shown that natural scaffolds which maintaine their main structure and properties could be a suitable tool for studying cellular behaviors and preparation of such scaffolds is an important part of future research in biology that may have extensive applications in regenerative medicine and tissue engineering. Blastema tissue which is produced after injuries in some organisms has embryonic cell characteristics, and can be a suitable model for evaluation of cell behaviors in various tissues. In this review, the process of decellularization, process involved in preparation of 3D scaffolds derived from extracellular matrix of various tissues including cartilage, bone, gingiva, aorta and bladder, and assessment of their interactions with blastema tissue under in vitro conditions are discussed.

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Background and Objective: Compression or sciatic axotomy induces neuronal death in spinal cord alpha motor neuron. This study was carried out to determine the effect of Nigella sativa seed alcoholic extract on spinal motor neuron density in anterior horn after sciatic nerve compression in rat. Materials and Methods: In this experimental study 24 wistar rats were divided into four groups A: control, B: compression, C: compression+treatment with 75 mg/kg alcoholic extract, D: compression+treatment with 50 mg/kg alcoholic extract. In control group muscle was exposed without any injury to sciatic nerve. In compression and treatment group, the right leg sciatic nerve compressed for 60 sec. After four weeks of post operation, L2-L4 and S1, S2 and S3 segments of spinal cord were sampled, processed, serially sectioned and stained with toluidine blue. The number of alpha motor neurons was counted using dissector method. Results: Neuronal density in compression group (650±32) significantly decreased in comparison with control group (1803±24). Neuronal density in C treated group (1581±47) and D treated group (1543±49) significantly increased compare to compression group (P<0.001). Conclusion: Alcoholic extract of Nigella sativa seed increased the density of alpha motor neurons in spinal cord after sciatic nerve compression in rats.