Com o objetivo de estudar a hidroxiapatita sintética (HAP-91) como substituto ósseo, foram utilizados oito cães adultos, sem raça definida, clinicamente sadios. Após protocolo anestésico e cirúrgico habituais, foi provocado um defeito ósseo na diáfise proximal das tíbias esquerda e direita, sendo implantada a HAP-91 apenas na tíbia direita. Os animais, dois de cada vez, foram sacrificados aos 8, 30, 60 e 120 dias após a cirurgia, quando foram obtidas amostras do local da lesão, que foram fixadas, lavadas, polimerizadas, cortadas e submetidas a dupla coloração em solução aquosa de acetato de uranila a 1% e em solução de citrato de chumbo. Essas secções foram avaliadas e fotografadas ao microscópio eletrônico de transmissão. Os componentes tissulares na tíbia tratada e na controle foram similares. A absorção da HAP-91 caracterizou-se pela presença de células multinucleadas na interface entre HAP-91 e osso, morfologicamente consideradas como osteoclastos. Ainda, encontraram-se grânulos de HAP-91 no interior de células morfologicamente caracterizadas como macrófagos. A absorção celular de grânulos de HAP-91, concomitante com a formação adjacente de osso novo, sugere que a osteointegração da HAP-91 seja análoga ao processo normal de reabsorção-aposição óssea.

BackgroundThere are not reported regarding the protocols for obtaining platelet concentrates (PC) in cats for medical purposes. The objectives of this study were: 1) to describe a manual method for producing two kinds of PC in cats (PC-A and PC-B), 2) to describe the cellular population of the PC, 3) to measure and compare the effect of calcium gluconate (CG) and bovine thrombin (BT) on the temporal release of transforming growth factor beta 1 (TGF-β1) and platelet-derived growth factor type BB (PDGF-BB) at 3 and 12 hours post-activation and 4) to establish correlations between the cellular population of both PCs and the concentration of growth factors (GF). Blood samples were taken from 16 cats for complete blood count, plasma collection and PC preparation. The PC were arbitrarily divided into two fractions, specifically, PC-A (lower fraction) and PC-B (upper fraction).ResultsThe platelet counts were significantly different (P<0.05) between the PC and whole blood but not between the PC fractions. The TGF-β1 concentration efficiencies for PC-A and PC-B activated with CG were 42.86% and 46.54%, and activated with BT were 42.88% and 54.64%, respectively. The PDGF-BB concentration efficiencies for PC-A and PC-B activated with CG were 61.36% and 60.61%, and activated with BT were 65.64% and 72.12%, respectively. The temporal release of GFs showed no statistically significant difference (P>0.05) between the activating substances at the time or for any PC fraction.ConclusionsWhatever the activation means, these preparations of cat PC provide significant concentrations of platelets and GFs for possible clinical or experimental use.

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BackgroundThe aim of the present study was to compare the osteogenic potential of mesenchymal stem cells extracted from the bone marrow (BM-MSCs) and adipose tissue (AD-MSCs) of young dogs. The following parameters were assessed: dimethyl thiazolyl diphenyl tetrazolium (MTT) conversion, alkaline phosphatase (ALP) activity, collagen and mineralised matrix synthesis, and the expressions of osterix, bone sialoprotein (BSP), and osteocalcin (OC).ResultsMTT conversion was greater in BM-MSCs compared to AD-MSCs after 14 and 21 days of differentiation; ALP activity was greater in differentiated AD-MSCs on day 7; collagen synthesis was greater in BM-MSCs on days 14 and 21; the percentage of mineralized area per field was greater in BM-MSCs compared to AD-MSCs; osterix expression was greater in BM-MSCs in days 14 and 21, and BSP and OC expression levels were greater in BM-MSCs at all the investigation time-points.ConclusionsIt was concluded that the osteogenic potential was greater in BM-MSCs than AD-MSCs when extracted from young dogs.

Our results indicate that autologous PC might improve functional outcome after intra-articular cranial cruciate ligament repair. The effect of PC when using other repair procedures warrants additional studies.