This study focuses on evaluating accumulation of the low molecular
peptides and
proteins labelled with 99mTc in rat inflammatory/
infection foci.
Peptides (human leukocyte
dialysate, HLD;
thymosin fraction 5, TF5;
aprotinin,
APT), and
proteins (human
IgG, HIG) were labelled with 99mTc using redox
polymer. The labelling efficiency was evaluated using paper, TLC and/or column chromatography. Biodistribution of labelled substances was evaluated in rats with
Staphylococcus aureus infection or with sterile
kaolin suspension inflammation 24 h after
abscess induction. Accumulation of 99mTc activity was determinated both by external
gamma camera imaging and by counting dissected tissues 4 h after administration. The evaluated
peptides and
proteins show high labelling efficiency (99mTc-HLD>98%, 99mTc-TF5>95%, 99mTc-
APT>98%, 99mTc-HIG>95%). Usage of redox
polymer for labelling increases the stability of 99mTc-labelled substances. The labelling efficiency stays nearly the same (95-98%) after 8 h at least. In experimentally induced
inflammation the amount of 99mTc-peptides and 99mTc-HIG activity accumulated is 2.5-6.5 and 5.3-10.6 times higher than in a control tissue. When comparing two types of model
inflammations (
kaolin- and Staphylococcus-induced ones), the values measured with 99mTc-peptides are more than double than those of
kaolin suspension inflammation. The studied low molecular
peptides labelled with 99mTc allow rapid localisation of
infection foci. 99mTc labelled HIG proved useful for detection of
infections and inflammatory lesions.