Análise in vitro da citotoxicidade em osteoblastos de dispositivos poliméricos incorporados com antimicrobianos para uso local

Abstract

Lage TC. In vitro analysis of cytotoxicity in osteoblasts of polymer devices incorporated with antimicrobials for local use [dissertation] São Paulo: Universidade de São Paulo, Faculdade de Odontologia; 2017. Versão Corrigida. Osteoblasts are mesenquima originated cells, which are involved in the bone formation. These cells may suffer alterations due to traumas, interventions and infeccions. The infections can be minimized by the handling of antimicrobials. Poly (L-lactide) or PLLA is a synthetic polymer known for its biocompatibility and absorption, which can be used as a local pharmacological releaser, as an alternative to the systemic antimicrobial therapy. This polymer also can be frequently used as a supporting structure to cellular matrix in the bone tissue engineering as it can be used for support in repair and regeneration. The particle incorporation in this polymer can create side effects, therefore, we need to certificate that the polymeric device incorporated with antimicrobials are not cytotoxic. Proposition: Analyse the structure and cytotoxicity in osteoblasts of PLLA polymeric devices associated with antimicrobials, being them: Amoxicillin, Azithromycin, Clindamycin and Metronidazole. Methods: For this study 270 polymerical devices were manufactured with 6mm diameter of PLLA with a 20% antimicrobials incorporation of Amoxicillin (AM), Azithromycin (AZ), Clindamycin (CL) and Metronidazole (ME) that have been produced through two methods: eletrospinning (mesh) or casting (film). Afterwards a MTT cytotoxicity test was made over the periods of 24, 48 and 72 hours of experiment. To make a structural analysis of the device a macroscopic analysis was performed through photographs and microscopic imaging with scanning electron microscope (SEM). Results: The cytotoxicity reaction exhibited that meshes and films incorporated with antimicrobials are comparable with the osteoblasts culture, indicating that there was no cytotoxicity in any moment (p < 0.05). In the phothograph we could observe that the devices showed a similar coloration among the meshes and different coloration for the films depending on the incorporated antimicrobial. The SEM analysis displayed a difference in the surface appearance of the films. The AM films displayed an irregular and porous appearance, meanwhile, AZ looked smooth with few grains, the CL and ME have rough surfaces and PLLA presents smooth surfaces. As for the meshes, we noticed that all the samples had microfibers and pores that mimic the extracellular matrix, differing only in the thickness of the fibers. Osteoblasts were present in all films but AM did not induce proliferation, with only isolated cells emerging. In meshes osteoblasts were only found in AM, ME and PLLA. Conclusion: Polymeric devices made with PLLA incorporated with antimicrobials can be used in bone repair and regeneration given that they did not offer cytotoxicity for osteoblasts.

Síntese, caracterização e estudo in vitro do potencial de mineralização do composto Quercetina-Sr>sup<2+>/sup<

“…Apesar de sua capacidade de auto-regeneração, defeitos críticos causados por trauma ou mesmo por patologias como osteoporose, osteomalácia, no hiperparatiroidismo, na osteogênese imperfeita, entre outras, podem não ser naturalmente preenchidos 3 . Na odontologia defeitos ósseos resultantes da reabsorção (quebra do equilíbrio no processo de remodelação) são recorrentes de infecções causadas por bactérias que se encontram ao redor do dente ou do implante 12 . Souza et al 13 cita que diversos processos patológicos (lesões periapicais, cistos, neoplasias e doença periodontal) geram lesões na cavidade bucal e reabsorção do osso circundante, afetando o metabolismo do tecido.…”