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Previous issue date: 2017-07-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The increasing incidence of tendon injuries is a constant challenge in orthopaedic medicine.
The use of platelet-rich plasma (PRP) is a strategy widely explored in the clinic because it is
believed to accelerate the tendon repair process. However, the PRP clinical efficacy is
uncertain, and more studies that aim to a better understanding of this treatment are needed.
The aim of this research was to evaluate the PRP effect on the Achilles tendon (AT) repair of
rats. A total of 242 rats were used, where 181 animals were randomly distributed in 6
different experiments. The remaining animals were used as blood donors (n=49) and for flow
cytometry (n=12). The lesion was performed by transection of the right AT. The repair
evaluation occurred after 11 and 14 postoperative days, with a mechanical testing machine.
Peak force was considered the primary variable. Variations in the PRP production protocols,
leukocyte concentration and physical activity of the rats were tested. ELISA test was
performed to quantify platelet-derived growth factor (PDGF-AB) present in PRP. Pathogenfree
animals and animals contaminated with Staphylococcus aureus (S. aureus) were used.
Standard PRP platelet concentration was at least 5 times higher than that of the peripheral
blood, and it was possible to have either a high or a low leukocyte concentration in the
preparation. PDGF-AB levels in inactivated PRP were 7.3 ?g/mL (SD 6.0; n=4) and in
plasma were below the detection levels (0.03 ng/mL). In the experiments performed with
pathogen-free rats, no significant effect of PRP could be observed on tendon repair. In the
same way, no significant difference could be found in the rats treated with PRP with higher or
lower leukocyte concentration. In contrast, rats contaminated with S. aureus showed increased
tendon force after PRP treatment. Significant interaction between bacteriological status and
PRP treatment was verified (p=0.003). It was further observed that healthy rats had higher
levels of cytotoxic T cells in their spleens. The difference in response to treatment in
contaminated rats suggests that the PRP effect is dependent on the immune status of the
animals. This is the first study that suggests the possibility of interaction between microbiota
and tendon repair. Extrapolation of this treatment to the clinic remains dubious. / A crescente incid?ncia de les?es tend?neas constituem um desafio constante na medicina
ortop?dica. A utiliza??o do plasma rico em plaquetas (PRP) ? uma estrat?gia amplamente
explorada na cl?nica por creditar-se que acelera o processo de reparo tend?neo. Contudo, a
efic?cia cl?nica do PRP ? question?vel, e mais estudos que visem uma melhor compreens?o
deste tratamento s?o necess?rios. O objetivo desta pesquisa foi avaliar o efeito do PRP no
reparo do tend?o de Aquiles (TA) de ratos. Um total de 242 ratos foram utilizados, sendo 181
animais randomicamente distribu?dos em 6 diferentes experimentos. Os animais restantes
foram utilizados como doadores sangu?neos (n= 49) e para realiza??o de citometria de fluxo
(n=12). A les?o foi executada atrav?s de transec??o do TA direito. A avalia??o do reparo foi
feita 11 e 14 dias p?s-cir?rgico, atrav?s de m?quina de teste mec?nico. O pico de for?a foi
considerado a vari?vel principal. Varia??es no protocolo de produ??o de PRP, concentra??o
de leuc?citos e atividade f?sica dos ratos foram testados. O teste de ELISA foi realizado a fim
de quantificar o fator de crescimento derivado das plaquetas (PDGF-AB) presente no PRP.
Foram utilizados animais livres de pat?genos e animais contaminados com Staphylococcus
aureus (S. aureus). A concentra??o plaquet?ria do PRP padr?o foi pelo menos 5 vezes maior
que a do sangue perif?rico, e foi poss?vel obtermos tanto uma alta ou baixa concentra??o de
leuc?citos no preparado. Os n?veis de PDGF-AB no PRP inativado foram de 7.3 ?g/mL (DP
6.0; n=4) e no plasma sangu?neo foram abaixo dos n?veis de detec??o (0.03 ng/mL). Nos
experimentos realizados com ratos livres de pat?genos, nenhum efeito significativo do PRP
p?de ser observado no reparo tend?neo. Da mesma forma, nenhuma diferen?a significativa
p?de ser encontrada nos ratos tratados com PRP com alta ou baixa concentra??o de
leuc?citos. Em contraste, os ratos contaminados com S. aureus demonstraram aumento da
for?a tend?nea ap?s o tratamento com PRP. Significante intera??o entre estado bacteriol?gico
e tratamento PRP foi verificada (p=0.003). Observou-se ainda, que ratos saud?veis possu?am
maiores n?veis de c?lulas T citot?xicas em seus ba?os. A diferen?a na resposta ao tratamento
em ratos contaminados sugere que o efeito do PRP ? dependente do estado imune dos
animais. Esse ? o primeiro estudo que sugere a possibilidade de intera??o entre microbiota e
reparo tend?neo. A extrapola??o deste tratamento para a cl?nica permanece d?bia.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/7754 |
| Date | 26 July 2017 |
| Creators | Dietrich, Franciele |
| Contributors | Silva, Jefferson Lu?s Braga da, Bampi, Vin?cius Faccin |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Medicina e Ci?ncias da Sa?de, PUCRS, Brasil, Escola de Medicina |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 7620745074616285884, 500, 500, 500, 600, -224747486637135387, -969369452308786627, 2075167498588264571 |
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