5th EuropEan MolEcular IMagIng MEEtIng - ESMI

5th EuropEan MolEcular IMagIng MEEtIng – EMIM2010
Development of dorsal skin-fold window chamber for the analysis of blood vessel
modifications induced by electropermeabilization
Golzio M. (1) , Bellard E. (1) , Markelc B. (2) , Cemazar M. (2) , Sersa G. (2) , Teissie J. (1) .
(1) IPBS-CNRS, Toulouse, France
(2) Institute of Oncology, Slovenia
muriel.golzio@ipbs.fr
Introduction: Recent developments in intravital microscopy
(IVM) enable studies of tumour angiogenesis
and microenvironment at the cellular level after
different therapies. Preparation of skin fold chamber
enables to follow fluorescent events on live animal.
Electroporation/electropermeabilization, i.e. application
of electric pulses to tissues, is a physical method
for delivery of exogenous molecules. It is already used
in clinical therapies of cancer, for electrochemotherapy
of tumors (ECT). Its use was recently developed
in electrogene therapy (EGT). In vivo, “electroporation”
is associated with a blood -flow modifying effect
resulting in decreased blood flow.
The aim of our study was to observe directly on the
living animal the effects of “electropermeabilization”
on subcutaneous normal blood vessels by monitoring
changes in morphology (diameter) and dynamics
(vasomotricity, permeability and recovery).
Methods: These parameters were measured using
fluorescently labelled dextrans injected in the
blood vessels observed via a dorsal skin fold window
chamber, intravital digitized stereomicroscope,
in vivo intravital biphoton microscopy and custom
image analysis. A mathematical modelling gave access
to the changes in permeability from the time
lapse observation. Delivery of electric pulses was
operated on the microscope stage directly on the
animal under anaesthesia.
Results: It resulted in immediate constriction of
blood vessels that was more pronounced for arterioles
(up to ~65%) compared to venules (up to ~20%).
A rapid increase in vascular permeability was present
that gradually decreased to basal (control) levels at
1 h post-treatment. The decay of the high increase
in vascular permeability was biphasic with an initial
fast decrease, but was still present at 1h post-treatment.
Furthermore, vasoconstriction of arterioles after
“electropermeabilization” resulted in a “vascular
lock” that remained for at least 6 minutes. This correlated
approximately with the duration of decreased
diameters of arterioles that lasted for 8 minutes.
Conclusions: the results of our study provided
direct in vivo monitoring of a vascular effect of
electric pulses on normal vessels. The observed
increase in permeability of vessels associated
with delayed perfusion induced by electric pulses
explains the improved delivery of molecules into
tissues induced by this method after systemic
delivery.
Acknowledgement: CNRS, Region Midi Pyrenees,
ARC, canceropole GSO, ANR “Cemirbio”, Slovenian
French Proteus
References:
1. Cemažar M, Golzio M, et al. Current Pharmaceutical
Design 12: 3817-3825. (2006).
2. Marty M, et al. EJC 4(11): 3-13. (2006).
3. Sersa G, et al. Br J Cancer; 98: 388-398 (2008).
4. Golzio M., et al. Gene Therapy 11, S85-S91 (2004).
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