The effect of phagocytosis of poly(L‐lactic acid) fragments on cellular morphology and viability

Abstract

The aim of this study was to investigate the effect of phagocytosed poly(L-lactic acid) particles on the morphology and viability of phagocytes, mainly macrophages. Therefore, predegraded poly(L-lactic acid) (P-PLLA) and nontreated PLLA (N-PLLA) particles, both having diameters not exceeding 38 microns, were injected intraperitoneally in mice. P-PLLA particles were obtained by 25 kGy gamma-irradiation of N-PLLA particles. N-PLLA and P-PLLA particles were injected using an 0.3% ethanol/0.9% saline solution intraperitoneally to the mice. We also studied the release of the absorbed ethanol as a possible model for the release of low molecular weight, potentially toxic products. As control, nondegradable polytetrafluoroethylene (PTFE) particles and the carrier solution were used. After 1, 2, 3, 4, 5, and 7 days, the cells of the abdominal cavity were harvested to study the effect of phagocytosis of polymer particles on phagocytic cell morphology and viability. Studies with transmission electron microscopy indicated that, upon injection of particles in the peritoneal cavity, macrophages demonstrated signs of cell damage, cell death, and cell lysis due to phagocytosis of a large amount of P-PLLA particles. The morphology of the cells that had phagocytosed the N-PLLA and PTFE particles did not differ substantially from those of control animals in which only the solution was injected. Also, in the controls, hardly any cell death and no debris was observed. When the PLLA particles were injected as a suspension in a 0.3% ethanol/0.9% saline solution, no difference was observed between N-PLLA and P-PLLA. After phagocytosis, both cause cell damage, sometimes leading to cell death.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of poly (L-co-D,L Lactic Acid) and a study of polymer-tissue interaction in subcutaneous implants in wistar rats

“…This work was supported by grants from PIBIC/CEPE (Programa Institucional de Bolsas de Iniciação Científica -Conselho de Ensino Pesquisa e Extensão). response [28][29][30][31] . Foreign body giant multinuclear cells are small phagocytes that possess a large number of lysosomes and high respiratory enzymatic activity.…”

Targeted Intracellular Delivery of Antituberculosis Drugs to Mycobacterium tuberculosis-Infected Macrophages via Functionalized Mesoporous Silica Nanoparticles

“…Liposomes and solid lipid particles have intrinsically poor chemical stability and are degraded by serum (16), thereby decreasing drug delivery to the target cells while increasing potential systemic toxicity. There is also concern that macrophage uptake of biodegradable polymer-based nanoparticles (such as poly-L-lactide and PLGA) may cause cell damage, cytokine release, and inflammation (24,32,42), although evidence of their benign nature and lack of associated histopathology has also been reported (11,41). In contrast to these potential problems with liposomal and biodegradable polymer delivery systems, preliminary in vivo experiments have found enhanced blood stability of MSNP compared with liposomes and polymeric nanoparticles (4) and have demonstrated favorable biocompatibility, biodegradation and excretion properties (18,29,45).…”

Overview on Biocompatibilities of Implantable Biomaterials

“…It was reported that, after the PLLA segments were swallowed in vivo by phagocytes, cell damage and cell death were obvious. The highest numbers of necrotic cells were observed on day 2 [154]. These reactions can result in an unexpected risk for patients and have strongly limited in clinical applications of this kind of biomaterials.…”