Date Published: February 28, 2019
Publisher: Sociedade Brasileira para o Desenvolvimento da Pesquisa em
Author(s): Cristina Pires Camargo, Renan Dias Frassei, Daniel Imbassahy de Sá Bittencourt Camara e Silva, Robert Zawadzki Pfann, Luiza de Campos Moreira da Silva, Julio Morais-Besteiro, Rolf Gemperli.
To evaluate the hyaluronic acid (HA) inflammatory reaction, fibroblasts,
fibrosis and duration of effect in the dorsal region of tobacco-exposed
Ten Wistar rats were divided into two groups: tobacco-exposed-group (TEG;n=5)
and air-control-group (CG;n=5). The TEG animals were tobacco-exposed twice a
day, 30-minutes/session, during 60 days. After this period, all animals
received 0.1 mL HA subcutaneous injection in the dorsal area. The volume of
HA was measured immediately after HA injection and weekly using a
hand-caliper in nine weeks. After this period, all the animals were
euthanized, and a specimen of was collected to evaluate inflammatory cells,
fibroblasts, and fibrosis by HE.
This study showed a higher inflammatory reaction in TEG than CG: inflammatory
cell-count (CG: 1.07±0.9; TEG: 8.61±0.36, p<0.001); fibroblast count (CG: 2.92±0.17; TEG: 19.14±0.62, p<0.001), and fibrosis quantification (CG: 2.0; TEG: 3.75, p<0.001). The analysis of the HA volume in nine weeks in the dorsal region did not show a difference between groups (p=0.39). This study suggested that the HA injection in the TEG caused an increase in inflammatory cell count, fibroblast, and fibrosis quantification when compared to the CG. There was no difference in the duration of effect of HA between the groups.
All implantable substances promote inflammatory reaction represented by an elevation
of the inflammatory cell count (acute phase) and fibroblast deposition (long-term
This study was approved by the Ethical Committee of the School of Medicine,
Universidade de São Paulo (050/16). All animal management was in accordance with the
International Council for Laboratory Animal Science.
All animals survived during the study without any local or systemic
This study showed a higher inflammatory reaction in TEG than in the Control group.
All implantable substances promote inflammatory reaction represented by a high
inflammatory cell count (acute phase) and fibroblast deposition (long-term
This study suggested that the HA injection in the tobacco-exposed group showed an
increase in inflammatory cell count, fibroblast count, and fibrosis quantification
when compared to the control group. There was no difference in the duration of
effect of injected HA in the tobacco-exposed and control group.