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OBJETIVO: Avaliar se a injeção intra-articular de Plasma rico em plaquetas (PRP) pode reduzir a apoptose pós-traumática de condrócitos. MÉTODOS: Foi desenvolvido um estudo experimental duplo-cego com quatro joelhos de coelhos adultos. Após a anestesia, os animais foram submetidos à contusão padronizada dos joelhos. Depois foi injetado 1ml de PRP humano nos dois joelhos esquerdos e 1ml de solução fisiológica (SF) nos dois joelhos direitos. Os dois coelhos foram mantidos no mesmo ambiente sob controle de temperatura, de atividades diárias e de alimentação. A eutanásia dos animais ocorreu dez dias após a intervenção e foram realizadas biópsias da cartilagem de cada joelho. As peças foram preparadas para análise em microscopia eletrônica (ME). RESULTADOS: Quatro preparados para ME foram obtidos, cada um correspondendo a um joelho. Os joelhos-PRP apresentaram as taxas de apoptose de 47,62 por cento (50/105) e de 48,36 por cento (59/122), respectivamente. Nos joelhos-SF as taxas de apoptose foram, respectivamente, 56,67 por cento (17/30) e 70,40 por cento (88/125). A diferença do índice de apoptose nos joelhos-PRP (48,02 por cento) e nos joelhos-SF (67,74 por cento) foi significante (p<0,001) e OR=0,439 (IC95 por cento=0.287-0.673). CONCLUSÃO: A injeção intra-articular de PRP imediatamente ao trauma, reduz as taxas de apoptose (pós-traumática) de condrócitos de coelhos.

OBJECTIVE: To evaluate if the injection of intra-articular platelet-rich plasma (PRP) can reduce impact-induced chondrocyte apoptosis. METHODS: A double-blind experimental study was developed in four knees of two adult rabbits. Each knee was injured after anesthesia. Subsequently, 1ml PRP was injected in the right knees and 1ml of normal saline (NS) in the left knees. The animals were euthanized ten days after the intervention. All cartilage was removed from the 4 knees and prepared for analysis in electron microscopy (EM). RESULTS: Four EM samples were obtained. The PRP-injected knees showed apoptosis rates of 47,62 percent (50/105) and 48,36 percent (59/122), respectively. NS-injected knees showed 56.67 percent (17/30) and 70.40 percent (88/125) of apoptosis. PRP-injected knees had statistically significant less apoptosis (48.02 percent) than NS-injected ones, (67.74 percent, p<0,001) and odds ratio of 0.439 (95 percent CI=0.287-0.673). CONCLUSION: Immediately post-traumatic intra-articular injection of PRP reduces impact-induced chondrocyte apoptosis in rabbits.

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STUDY DESIGN: Controlled laboratory study. OBJECTIVE: To evaluate the effect of low-intensity therapeutic ultrasound on the murine calcaneus tendon healing process. BACKGROUND: Therapeutic ultrasound promotes formation and maturation of scar tissue. METHODS: Calcaneus tendon tenotomy and tenorrhaphy was performed on 28 Wistar rats. After the procedure, the animals were randomly divided into 2 groups. The animals in the experimental group received a 5-minute ultrasound application, once a day, at a frequency of 1 MHz, a spatial average temporal average intensity of 0.1 W/cm2, and a spatial average intensity of 0.52 W/cm2 at a 16-Hz frequency pulse mode (duty cycle, 20%). Data for the injured side were normalized in relation to the data from the contralateral healthy calcaneus tendon (relative values). The animals in the control group received sham treatment. After a 28-day treatment period, the animals were sacrificed and their tendons surgically removed and subjected to mechanical stress testing. The parameters analyzed were cross-sectional area (mm2), ultimate load (N), tensile strength (MPa), and energy absorption (mJ). RESULTS: A significant difference between groups was found for the relative values of ultimate load and tensile strength. The mean ± SD ultimate load of the control group was -3.5% ± 32.2% compared to 33.3% ± 26.8% for the experimental group (P = .005). The mean tensile strength of the control group was -47.7% ± 19.5% compared to -28.1% ± 24.1% for the experimental group (P = .019). No significant difference was found in cross-sectional area and energy absorption. CONCLUSION: Low-intensity pulsed ultrasound produced by a conventional therapeutic ultrasound unit can positively influence the calcaneus tendon healing process in rats.

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