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.

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.

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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.

BackgroundThe clinical use of autologous platelet concentrates (also known as platelet-rich plasma) on the field of regenerative therapy, in the last decade has been the subject of several studies especially in equine medicine and surgery. The objectives of this study was: 1) to describe and compare the cellular population in whole blood, lower fraction (A) and upper fraction (B) of platelet concentrates, 2) to measure and compare the transforming growth factor beta 1 (TGF-β1) concentration in plasma and both platelet concentrates after be activated with calcium gluconate or batroxobin plus calcium gluconate and, 3) to determine correlations between cell counts in platelet concentrates and concentrations of TGF-β1. Blood samples were taken from 16 dogs for complete blood count, plasma collection and platelet concentrates preparation. The platelet concentrates (PC) were arbitrarily divided into two fractions, specifically, PC-A (lower fraction) and PC-B (upper fraction). The Platelet concentrates were analyzed by hemogram. After activated with calcium gluconate or batroxobin plus calcium gluconate, TGF-β1 concentration was determined in supernatants of platelet concentrates and plasma.ResultsThere were differences statistically significant (P < 0.05) for the platelet count and leukocyte count and TGF-β1 concentration between whole blood, plasma and both platelet concentrates. A significant correlation was found between the number of platelets in both platelet concentrates and TGF-β1 concentration. Platelet collection efficiency was 46.34% and 28.16% for PC-A and PC-B, respectively. TGF-β1 concentration efficiency for PC activated with calcium gluconate was 47.75% and 31.77%, for PC-A and PC-B, respectively. PC activated with batroxobin plus CG showed 46.87% and 32.24% for PC-A and PC-B, respectively.ConclusionsThe methodology used in this study allows the concentration of a number of platelets and TGF-β1 that might be acceptable for a biological effect for clinical or experimental use as a regenerative therapy in dogs.

Quinze cães, sem raça definida, de ambos os sexos, de peso entre 18 e 25kg, foram submetidos à secção artroscópica do ligamento cruzado cranial (LCCr) para indução da doença articular degenerativa (DAD). Após três semanas de instabilidade articular, o LCCr foi substituído pela fáscia lata segundo a técnica de Schwalder (1989) e os animais foram distribuídos em três grupos de cinco. Os animais do grupo I, controle, não receberam tratamento medicamentoso; os do grupo II, 24mg/animal de sulfato de condroitina, por via IM, de cinco em cinco dias, totalizando seis aplicações; e os do grupo III foram tratados com hialuronato de sódio na dose de 20mg/animal, por via IV, de cinco em cinco dias num total de três administrações. Ao final de 90 dias, os animais foram eutanasiados e procedeu-se à colheita e ao processamento histológico da membrana sinovial e da cartilagem articular para avaliações morfológica e morfométrica. No grupo I foram observadas alterações degenerativas de DAD mais acentuadas que nos demais grupos, como redução do número de condrócitos, presença de pânus, fibrilações, fissuras, erosões e irregularidades na superfície articular. No grupo II observou-se elevação do número de condrócitos com aumento da atividade de síntese da matriz e redução das lesões na superfície da cartilagem. No grupo III houve aumento do número de condrócitos que eram, muitas vezes, morfologicamente inviáveis. Todos os grupos apresentaram proliferação da membrana sinovial e presença de infiltrado linfoplasmocitário na subíntima e na perivascular. Nos grupos I e III, a proliferação da membrana sinovial era exuberante com formação de pânus, presença de sinoviócitos achatados ou ausência de sinóvia com tecido de granulação. Os resultados sugerem que o sulfato de condroitina estimulou a cartilagem articular, diminuindo ou retardando as alterações da DAD e o hialuronato de sódio não interferiu no processo degenerativo da cartilagem articular. Não foi constatada ação favorável das drogas na membrana sinovial.

The development of a vaccine would be essential for the control of schistosomiasis, which is recognized as the most important human helminth infection in terms of morbidity and mortality. A new approach of oral vaccination with DNA-chitosan nanoparticles appears interesting because of their great stability and the ease of target accessibility, besides chitosan immunostimulatory properties. Here we described that chitosan nanoparticles loaded with plasmid DNA encoding Rho1-GTPase protein of Schistosoma mansoni, prepared at different molar ratios of primary amines to DNA phosphate anion (N/P), were able to complex electrostatically with DNA and condense it into positively charged nanostructures. Nanoparticles were able to maintain zeta potential and size characteristics in media that simulate gastric (SGF) and intestinal fluids (SIF). Further in vivo studies showed that oral immunization was not able to induce high levels of specific antibodies but induced high levels of the modulatory cytokine IL-10. This resulted in a significative reduce of liver pathology, although it could not protect mice of infection challenge with S. mansoni worms. Mice immunized only with chitosan nanoparticles presented 47% of protection against parasite infection, suggesting an important role of chitosan in inducing a protective immune response against schistosomiasis, which will be more explored in further studies.