Vol. 10, No 3, 2003 pp. 131 - 134
UC 615.46:612.753 
CHANGES OF HAp/PLLA BIOCOMPOSITES AND TISSUE REACTION
AFTER SUBCUTANEOUS IMPLANTATION
S. Najman1, Lj. Đorđević1, V. Savić1, N. Ignjatović2, M. Plavšić3, D. Uskoković2
1 Institute of Biomedical Research, Medical Faculty, Niš, Serbia
2 Institute of Technical Science, SANU, Belgrade, Serbia
3 Faculty of Technology, Belgrade, Serbia

Summary. Experimental and clinical studies have shown that HAp granules and powder may be successfully applied in reconstruction of bone defects. Composite HAp/PLLA biomaterial embodies good characteristics of each of these biomaterials. Differences in porosity, microstructure, compressive consistency as well as in bioresorbility of HAp/PLLA are achieved by using PLLA of different mole masses. The aim of this study was to analyse light microscopy of the tissue reaction and changes of implants made of combination of syngeneic bone fragments and HAp/PLLA biocomposites with PLLA molecule mass of 430 000 (HP2) and 50 000 (HP3). The mice were divided into 4 experimental studies, 8 animals each. Two groups underwent implantation, one group of mice was falsely operated, and one group was used for general control. Pathohistological analysis of implants was performed three months after subcutaneous implantation.  Phagocytosis of HAp/ PLLA and bone was noticed on both implants' preparations. Blood vessels were also noticed, confirming the process of angiogenesis around the implants' particles. The holes around particles of biocomposites and bone fragments represented the signs of their resorption. The presence of multinuclear cells between implants' particles was observed and it was more prominent in HP3 implants. Osteogenesis is more intense in HP3 and ectopic hematopoesis is present. Our results show that designed HAp/PLLA biocomposites have good biocompatibility, their combination with bone fragments of a vital bone enables osteogenesis and hematopoesis and these processes are more prominent if PLLA biocomposite with lower molecular mass was used.
Key words: Subcutaneous implantation, hidroxyapatite, polylactide, biocomposite

PROMENE BIOKOMPOZITA HAp/PLLA I REAKCIJA TKIVA
POSLE SUBKUTANE IMPLANTACIJE
Kratak sadržaj: Eksperimentalna i klinička istraživanja su pokazala da se granule i prah HAp mogu uspešno primeniti za rekonstrukciju koštanih defekata. Kompozitni biomaterijal HAp/PLLA objedinjuje dobre osobine koje poseduje svaki od ovih biomaterijala. Razlike u poroznosti, mikrostrukturi, kompresionoj čvrstoći kao i bioresorbilnost HAp/PLLA postižu se korišćenjem PLLA različitih molskih masa. Cilj rada je bio da se svetlosnom mikroskopijom analiziraju odgovor tkiva i promene implantata napravljenih od kombinacije singenih koštanih fragmenata i biokompozita HAp/PLLA sa PLLA molekulske mase od 430 000 (HP2) i 50 000 (HP3). Miševi su bili podeljeni u 4 eksperimentalne grupe od po 8 životinja. U dve grupe je urađena implantacija, jedna grupa miševa su bili lažno operisani, a jedna grupa je služila kao opšta kontrola. Posle 3 meseca od subkutane implantacije rađena je patohistološka analiza implantata. Na preparatima oba tipa implantata se vidi fagocitoza HAp/PLLA i kosti. Takođe su vidljivi krvni sudovi koji svedoče o procesu angiogeneze u okolini partikula implantata. Prazna polja oko partikula biokompozita i koštanih fragmenata predstavljaju znake njihove resorpcije. Vidljivo je prisustvo multinuklearnih ćelija između partikula implantata, a to je izraženije u HP3  implantatima. U HP3 je intenzivnija osteogeneza i prisutna je ektopična hematopoeza. Naši rezultati pokazuju da dizajnirani biokompoziti HAp/PLLA imaju dobru biokompatibilnost, da je u njihovoj kombinaciji sa koštanim fragmentima žive kosti moguća osteogeneza i hematopoeza i da su ovi procesi izraženiji ako je u biokompozitu PLLA manje molekulske mase.
Ključne reči: Subkutana implantacija, hidroksiapatit, polilaktid, biokompozit