M. Tomita et al., ACTIVATED LEUKOCYTES, ENDOTHELIAL-CELLS, AND EFFECTS OF PENTOXIFYLLINE - OBSERVATIONS BY VEC-DIC MICROSCOPY, Journal of cardiovascular pharmacology, 25, 1995, pp. 34-39
Using video-enhanced contrast (VEC)-differential interference contrast
(DIC) microscopy, ultrastructural observations were made of the activ
ation of polymorphonuclear leukocytes (PMNLs), the interaction between
activated PMNLs and endothelial cells (ECs), and the effects of pento
xifylline (PTX). The ECs were obtained from a commercial source as hum
an umbilical cord vein endothelial cells (HUVECs) or were obtained fro
m pig or rat brains. They were cultured on a coverglass with DMEM for
about 1 week. The human PMNLs were obtained from the authors' venous b
lood. The control appearance of the PMNLs resembled an elastic ball co
vered with fine villi. The PMNL was activated spontaneously and became
flattened on the glass surface within 10 min in the observation chamb
er. The activation of the PMNLs was estimated arbitrarily from the pol
ymorphous changes in cell shape, agitation of the intracellular granul
es, and apparent increase in adhesiveness. Preadministered PTX prevent
ed such PMNL activation, and the PMNLs remained round for more than 15
min. PMNL activation was accelerated by chemoattractants (PAF, fMLP,
and PMA). In one case, a PMNL that had been activated by PMA tended to
recover its round shape with PTX, but finally ended by swelling and b
ursting. When PMNLs were introduced into the EC-containing chamber, th
ey became entrapped by the ECs and activated, with degranulation follo
wed by release of a smoke-like material. After about 3 h, the EC with
an attached PMNL shrank and fell into a state of coagulation necrosis.
When PTX was introduced at the time of adhesion of the flattened PMNL
, the PMNL appeared to be deactivated, becoming smaller and assuming i
ts previous round shape, and detached from the EC. PTX prevented the s
pontaneous activation of PMNLs, and of deactivated PMNLs even after th
eir adherence to the endothelium.