Non-thermal atmospheric plasma stimulates new bone formation in critical
bone defects of animal model

Date:
October 29, 2021
Source:
Osaka City University
Summary:
A recent project has revealed new bone formation in critical
bone defects of an animal model with an exposure to a pencil-type
non-thermal atmospheric-pressure plasma at surgery.



FULL STORY ========================================================================== Recent technological innovations which have allowed plasma to be
generated at room temperature and at ambient atmosphere in what is called non-thermal atmospheric pressure plasma (NTAPP) have given scientists
from Japan the opportunity to apply the therapeutic properties of this
"fourth state of matter" to bone regeneration.


==========================================================================
In a study published in PLOS ONE, researchers from the Graduate School
of Medicine and the Graduate School of Engineering at Osaka City
University found a usefulness of NTAPP in healing of bone fractures
using a pencil-type NTAPP in animal bone defect models.

"NTAPP is considered a new therapeutic method," states first author
Akiyoshi Shimatani, "as it has been shown to accelerate cell growth
when applied at low enough levels." In an ambient atmosphere it can
generate highly reactive oxygen and nitrogen species (RONS) which can be directly exposed to biological targets like cells and tissues, according
to the researcher.

Indirect treatments have shown the potential advantages of plasma
in supporting the creation of stem cells that cause reactive oxygen
species and in inducing osteogenic differentiation and bone formation,
however, as the team points out there is no report on directly using
NTAPP for bone fracture therapy. "Direct exposure of NTAPP is a key
part of this study" states Jun-Seok Oh, professor at the OCU Graduate
School of Engineering and advisor to the study, "It required a device specifically designed to generate and deliver RONS to areas of the
bone defect 'effectively'." The research group developed a pencil-type
plasma device that can effectively generate and deliver RONS to an animal
model with a well-established critical bone defect, allowing the team
to search for the optimal irradiation conditions. Comparing groups that
were irradiated with NTAPP for 5, 10, and 15 minutes to control groups
with no plasma administered, micro-CT images at eight weeks showed the 10-minute treatment time as the most successful bone regeneration with
1.51 times larger bone volume than the control group.

"However, micro-CT images cannot determine whether a bone defect has
been filled with new bone, tissue, or both," says Hiromitsu Toyoda,
associate professor at the Graduate School of Medicine and supporting
author to the study. Therefore, the team also ran a histological analysis
and confirmed "bone defects in the groups treated with plasma were filled
with new bone and there was no inclusion, such as fiber tissue and gap
that was observed in the control group," continues the professor.

Like other forms of therapy, the biological effect of plasma depends on
the treatment dose delivered into the targets. Although future research
will be needed to clarify why the study saw the most bone regeneration
during the 10- minute treatment period, it is understood that surface wettability promotes greater cell spreading and adhesion to biomaterials
and implants. "We wondered if something similar was occurring where we
saw a strong generation of new bone." says Hiroaki Nakamura, professor at
the Graduate School of Medicine and advisor to the study, "and we found
that compared to the control group, bone surface of the plasma-treated
group as statistically and significantly more hydrophilic." While there
is still much to be explored and understood in terms of treatment dose,
for the first time ever, the direct application of room temperature, atmospheric plasma to a living body has seen a positive result. The
research team hopes the plasma device they developed can become something
used during surgery to bring the bone regeneration effect of NTAPP to
various medical fields.

========================================================================== Story Source: Materials provided by Osaka_City_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Akiyoshi Shimatani, Hiromitsu Toyoda, Kumi Orita, Yoshihiro
Hirakawa,
Kodai Aoki, Jun-Seok Oh, Tatsuru Shirafuji, Hiroaki Nakamura. In
vivo study on the healing of bone defect treated with non-thermal
atmospheric pressure gas discharge plasma. PLOS ONE, 2021; 16
(10): e0255861 DOI: 10.1371/journal.pone.0255861 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/10/211029103017.htm

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