R.J. Del Carlo

Efeitos do congelamento sobre condrócitos cultivados de coelhos

Avaliaram-se os efeitos do congelamento sobre condrocitos mantidos em cultura, com o objetivo de se estabelecer um banco celular para futura aplicacao como implante heterologo. Condrocitos extraidos da cartilagem articular de nove coelhos saudaveis, da raca Nova Zelândia Branca, foram cultivados e submetidos ao congelamento, com o citoprotetor sulfoxido de dimetila a 5%, por um periodo de seis meses. Analises fenotipicas e de microscopia eletronica de varredura foram realizadas com o objetivo de identificar diferencas morfologicas e funcionais entre as celulas frescas e as descongeladas. Apos a digestao enzimatica, foram obtidas 4,8x105 celulas por coelho. Os condrocitos frescos apresentaram elevada taxa mitotica e abundante presenca de matriz ate os 60 dias de cultura. Nas culturas dos condrocitos descongelados, a perda de estabilidade fenotipica foi marcante, o que foi demonstrado pela baixa intensidade da coloracao dos proteoglicanos e pela fraca imunomarcacao do colageno tipo II. Sob as condicoes de congelamento utilizadas, houve importante perda de viabilidade condrocitica. Para futuros estudos in vivo de implante heterologo, estes resultados sugerem que o elevado numero de celulas deve ser implantado no sitio hospedeiro, com o objetivo de se obter maior quantidade de celulas viaveis, e que os condrocitos deverao ser implantados com duas semanas de cultivo, periodo em que apresentam melhor taxa de viabilidade

Matriz óssea homóloga desmineralizada associada à medula óssea autógena fresca na artrodese vertebral dorsolateral lombar em coelhos

It was evaluated the homologous demineralized bone matrix (HDBM), associated with the fresh autogenous bone marrow (FABM), in the vertebral dorsolateral lumbar union in 24 rabbits (group 1), that was placed on the transverse processes of previously decorticated L5-L6 vertebrae. In other nine rabbits (control group), it was just accomplished the decortications of the transverse processes, which showed insignificant local periostial reaction, without bone union after different evaluations. In the group 1, after five weeks of postoperative interval, 87.5% of the animals presented union (arthrodesis), which was observed by palpation, followed by 75 and 100% after seven and nine weeks, respectively. The arthrodesis indexes to X rays were of 50%, 62% and 75%, in the same evaluation period. According to histological analysis, after five weeks, there were characteristics of osteointegration of HDBM with the decorticated transverse processes, from where the blood vessels that penetrated the bone matrix originated, and the presence of cartilage tissue in the center of the graft. In the following weeks, the endocondral ossification continued and HDBM was almost totally substituted by trabecular bone tissue, forming a bridge of ripe bone among and over the adjacent transverse processes, propitiating larger mechanical resistance to the operated segment in comparison to the adjacent segments. The association of HDBM with the FABM showed as a feasible option with low cost in the vertebral dorsolateral lumbar arthrodesis in rabbits.

Platelet rich plasma associated with heterologous fresh and thawed chondrocytes on osteochondral lesions of rabbits

Cultivaram-se condrocitos obtidos da articulacao do joelho de coelhos. Metade das celulas foi mantida em cultura para posterior implantacao, e a outra metade foi congelada durante seis meses com a finalidade de avaliar a viabilidade. Criou-se um defeito circular osteocondral no joelho direito de outros vinte e sete coelhos. O grupo controle (GC) nao recebeu tratamento. Os grupos descongelado (TH) e fresco (FH) receberam, respectivamente, implantes heterologos de condrocitos cultivados descongelados e frescos, associados com PRP. O grupo GC apresentou maior dor e claudicacao em comparacao com os outros grupos aos sete dias apos o implante. Microscopicamente, aos 45 e 90 dias, os grupos TH e FH mostraram preenchimento da falha com tecido cartilaginoso contendo condrocitos circundados por uma matriz densa de glicosaminoglicanos. Nesse periodo, no grupo CG, a cura ocorreu com tecido conjuntivo fibroso vascularizado e sem integracao com o osso subcondral. Condrocitos heterologos criopreservados foram viaveis para implantacao e tratamento de lesoes osteocondrais; a associacao com o PRP permitiu a fixacao de celulas na lesao e ofereceu fatores de crescimento que aceleraram a reparacao com o tecido semelhante a cartilagem hialina articular.

Quimionucleólise cervical associada à espondilectomia ventral em cães: aspectos clínico-cirúrgicos, radiográficos e histológicos

The clinical-surgical, radiological, and histological aspects of chemonucleolysis with chymopapain in canine cervical intervertebral disks associated to ventral slot in 24 dogs were evaluated. The ventral slot was accomplished in the area of the intervertebral disks C2-C3 and chemonucleolysis in the other cervical disks. The dogs were clinically and radiographically monitored for up to 120 days. Each group of four animals was submitted to euthanasia with an anesthetic overdose at 24 hours, and at 8, 30, 60, 90, and 120 days after the enzyme injection for the acquisition of sagittal sections of the treated disks, as well as adjacent cartilaginous endplates and bony structures. In this study, all dogs tolerated the surgical procedure, without detectable postoperative pain or neurological deficit. In the radiographic evaluation, it was observed consistent disk space narrowing 24 hours after the procedure and total absence of space from the 8th to the 90th day of postoperative in the area of all treated disks. However, 120 days after treatment, there was an increase in disk height, corresponding on average to 59.1% of the preinjection value. In the histological evaluation, it was observed nuclear digestion and decrease of safranin-O staining intensity 24 hours after disk injection. At eight days, the nuclear content was still vacuolated, but more fibrillar. An irregularly defined mass was observed in the nuclear space on days 60th and 90th, but it seemed fibrocartilaginous tissue on day 120th. Chemonucleolysis with chymopapain associated to the ventral slot in the cervical column of dogs determined lysis of intervertebral disks, cervical instability, and lesions of cartilaginous and bone adjacent structures that tend to repair with fibrocartilaginous tissue along the time.