the healing effect of conditioned media and bone marrow-derived stem cells in laryngotracheal stenosis: a comparison in experimental dog model

background differences in causes, severities, areas of stenosis, and the association with swallowing and phonation of larynx and trachea can result into laryngotracheal stenosis (lts).this study evaluated the healing effect of bone marrow stem cells (bmscs) in experimentally induced lts dog model. methods seven dogs were enrolled. bmscs were isolated from proximal humerus and shoulder of a dog and cultured in media containing alpha minimal essential medium, fetal bovine serum, penicillin and streptomycin, and l-glutamine. bmscs were characterized morphologically, by rt-pcr, and osteogenic induction. karyotyping was undertaken for chromosomal stability. mechanical trauma to laryngeal mucosa was identically conducted by tru-cut punch forceps in right and left vocal folds. two milliliter of conditioned media or bmscs (2×106) were injected in the right site of the tissue and the left side was considered as control after lts induction. the larynx was visualized 2, 4 and 6 weeks after treatment. six weeks post-treatment, the larynges were evaluated histologically. results bmscs were adhered to culture flasks, spindle shape and positive for mesenchymal marker and negative for hematopoietic markers. osteogenic induction was verified by alizarin red staining. karyotype was normal. a complete epithelialization and minimal chronic inflammatory cell infiltration were noted in submucosa of both left (control) and right (cases) vocal folds. the healing effect of conditioned media and bmscs in comparison to the control group was more prominent. conclusion as thickness of fibrosis in cases were less than control group, conditioned media and bmscs were shown to be good choices in healing of lts.