IMMUNOHISTOCHEMICAL CRITERIA OF PULMONARY ARTERY CIRCULAR DENERVATION EFFICIENCY IN EXPERIMENT (animals, pigs)

Authors

  • Trofimov N.A
  • Nikolskiy A.V
  • Rodionov A.L
  • Egorov D.V.
  • Surkova T.V

DOI:

https://doi.org/10.47750/pnr.2022.13.03.122

Keywords:

secondary pulmonary hypertension, radiofrequency ablation, denervation of pulmonary arteries, histological study

Abstract

Research objective. Evaluation of the influence of various modes of radiofrequency circular exposure on immunohistochemical parameters
of pulmonary trunk tissues in the experiment on animals (pigs).
Materials and methods. The experiments were made on outbred pigs – 12 animals. During the experiment 3 groups were formed, 4 animals
in each. The first experimental group comprised 188 histological samples of pulmonary artery (PA) after circular radiofrequency exposure
on PA using an ablator clamp. Two lines of ablation impact on the pulmonary trunk and two lines of impact on each mouth of PA were
performed with the formation of 6 ablation lines. The ablation was performed until the target level of tissue impedance between the ablator
jaws corresponding to the values for transmural damage was reached. The second experimental group comprised 162 histological samples
of PA after circular denervation of the pulmonary trunk and mouths of both PAs according to the described method. The ablation was
completed upon reaching 50% of the impedance level relative to the impedance values for transmural damage. The third group – control,
without circular radiofrequency exposure (55 histological samples). The obtained material was studied by light microscopy, typical general
pathological processes were recorded with the help of staining with hematoxylin and eosin. The changes in the connective tissue (fibrous,
muscle) were found with the help of Van Gieson staining. The thermoablative effect degree was assessed using semi-quantitative analysis
of pathological processes (Olpred stain intensity assessment). In order to assess the degree of impact on the nerve fibers of different layers
of PA, an immunohistochemical study (IHC) of the samples was carried out in all three groups. The expression of S-100 protein and
synaptophysin was evaluated.
Conclusion. Average optic density of the samples of the ablation groups was significantly lower than in the control group (p <0.001). When
calculating the specific area of the connective tissue disconnection, its greater value was determined in “the edge zones” of the sections in
both experimental groups, which is due to mechanical compression of tissues, compaction of their structure and, as a result, an increase in
capacitive characteristics as a current collector and conductor for radio frequency rate ( p = 0.056). IHC analysis of preparations made it
possible to qualitatively assess the damage to the trunks and endings of peripheral nerve fibers in the adventitial and intimal layers of PA
section after radiofrequency exposure in the experimental groups.
In the first experimental group the active expression of synaptophysin and protein S-100 of sympathetic nerve fibers was absent in the
adventitial and, as a rule, in the intimal layers. In the preparations obtained from PA of animals of the second experimental group, the activity
of synaptophysin in synaptic fibers and expression of protein S-100 of endothelium vasa vasorum were also not determined in the adventitial
layer. At the same time, the positive reaction of protein S-100 and synaptophysin was observed in the nerve endings and ganglia in the
intimal layer of PA preparations of the second group.
The circular denervation of PA using subthreshold rate of radiofrequency exposure corresponding to 50% of the impedance of PA tissues
from the corresponding impedance values in case of transmural damage, made it possible to avoid irreversible damage to the nerve endings
and ganglia of PA intimal layer, thereby preserving the physiological neuroreflex regulation of PA and entire pulmonary circulation. Thus,
the cascade of pathological reflexes, factors of pulmonary hypertension advance connected with the spasm of precapillary mouth of the
pulmonary arterioles is turned off.

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Published

2022-10-02

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Articles

How to Cite

IMMUNOHISTOCHEMICAL CRITERIA OF PULMONARY ARTERY CIRCULAR DENERVATION EFFICIENCY IN EXPERIMENT (animals, pigs). (2022). Journal of Pharmaceutical Negative Results, 13(3), 811-822. https://doi.org/10.47750/pnr.2022.13.03.122