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a

b
Figure 2: The results of TdT‑mediated dUTP‑X nick end labeling staining and the apoptosis index 72 h following ischemia‑reperfusion. (a) The evaluation
of apoptotic cell death by TdT‑mediated dUTP‑X nick end labeling staining in all groups. Apoptotic cell number was reduced with hyperbaric oxygen
preconditioning, hydrogen‑rich saline and hydrogen‑rich saline and hyperbaric oxygen preconditioning used cooperatively (brown staining indicates
apoptotic cells [red arrow]; ×200); (b) the apoptosis index of all groups. The data shown indicate the percentage of TdT‑mediated dUTP‑X nick end
labeling‑positive cells and the total cell nuclei per field. Three different slide fields from different skin tissues were counted. TUNEL: TdT‑mediated
dUTP‑X nick end labeling, IR: ischemia reperfusion, HBO: postoperative hyperbaric oxygen, HRS: hydrogen‑rich saline
P < 0.001). The expression of Bcl‑2 mRNA in the
HBO + HRS group (0.15 ± 0.05) was higher than in the
HBO group (0.08 ± 0.03) and HRS group (0.11 ± 0.05),
with statistically significant differences (HBO + HRS vs.
HBO, P < 0.001; HBO + HRS vs. HRS, P < 0.05) [Figure 5].

DISCUSSION

Flap transfer has become a basic albeit challenging
technique for all plastic surgeons given the high‑risk of
flap failure. Even in cases of microsurgical transfer with a
stable blood supply, skin flap loss still ranges between 1%
and 5% in experienced hands. [12,15] There are many reasons
for partial or total flap loss, including IR injury. During
Figure 3: Caspase‑3 activity in all groups 72 h following the process of IR injury, flap cells may change their
ischemia‑reperfusion. Compared to the ischemia‑reperfusion group, biochemical properties with the induction of apoptosis,
[16]
caspase‑3 activity was significantly inhibited in the hyperbaric oxygen,
[17]
hydrogen‑rich saline, and hyperbaric oxygen + hydrogen‑rich saline cell shrinkage, nuclear condensation, and cell death, [18‑20]
groups. IR: ischemia reperfusion, HBO: postoperative hyperbaric oxygen, leading to flap loss.
HRS: hydrogen‑rich saline
In clinical work, HBO has been widely used in the
ratio in the IR group (0.98 ± 0.40) was the lowest. treatment of challenging wounds and selected
Statistical differences were observed between HBO + neurological diseases. HBO is considered to be a successful
HRS vs. IR, P < 0.001; HBO vs. IR, P < 0.001; HRS vs. IR, adjunctive therapy for wound healing. In the plastic field,
P < 0.001; HRS vs. HBO, P < 0.001; and HBO + HRS vs. postoperative HBO treatment is commonly used following
HBO, P < 0.001. The highest Bcl‑2/Bax ratio was in the flap transfer with satisfactory improvement. There has
HBO + HRS group, but there was no significant difference also been research into the protective effect of HBO
between the HBO + HRS and HRS groups [Figure 4c]. therapy through preconditioning. Cheng found that HBO
reduced cyclooxygenase‑2 expression and provided brain
Bcl‑2 messenger RNA expression protection following ischemia. The current authors have
[4]
The messenger RNA (mRNA) levels in each group also examined the effects of HBO preconditioning in a
were determined with real‑time PCR. β‑actin was rat skin flap model and found an improvement in flap
used as a reference gene. Among all groups, the IR survival in IR injuries. The mechanisms responsible for
group (0.03 ± 0.03) showed the lowest level of Bcl‑2 its protective effect may be related to attenuation of the
mRNA expression with the exception of the sham group. inflammatory response and increased flap perfusion. [6]
Among surgery groups, there were significant differences
between the IR group and other groups (IR vs. HBO, Recently, other therapeutic gasses have been studied,
P < 0.01; IR vs. HRS, P < 0.001; IR vs. HBO + HRS, in particular, hydrogen. Hydrogen can reach relatively

336 Plast Aesthet Res || Vol 2 || Issue 6 || Nov 12, 2015