Results
I.
Adapting the experimental model to the study
The skin biopsies collected were analyzed using histopathology exam and found that a deep 2nd
degree burn can be obtained at device’s temperature of 42 Celsius degrees, with a contact time of
3 seconds on the flanks and at 48 Celsius degrees for 3 seconds on the legs.
II.
Finding the best wound dressing contention.
Trying to find the best way to keep the dressings in place was a real challenge. Several types of
dressing contention methods were tried, till we have found the best method to keep the dressing
in place, to keep the gel in contact with the burn area and to interfere less with the rabbit’s daily
activities.
a) The first type of contention was the simplest: just sterile dressing and retention bandages
circumferentially (peha haft®, Hartmann), but it felt down in the first 2 hours after the
effect of the anesthetics disappeared. We rebuilt the dressing, but this time the retention
bandages were more tighten up. It is hard to find the proper tension in the retention
bandages. This way, the dressings were in position, but 24 hours later, 9 of the rabbits
were dead and after 48 hours one more rabbit passed away.
The autopsy revealed hemorrhagic ulcers in the stomach, small intestine as a result of
post-traumatic stress and administration of NSAIDs, and pleural effusion and pulmonary
edema as a result of stasis, after circumferential bandage too tight in the abdomen.
The treatment with ketoprophen was stopped to the other rabbits and after reevaluation
the treatment with Fitomenadiona and Omeprazole was established for the next 4 days.
b) A new method of dressing fixation was tried: dressing fixation with skin staplers. These
way the dressings were in place a little longer, but the rabbits removed them with the
teeth leaving bleeding wounds on their skin, so we had to treat more wounds, possible
source of infection next to the clean burned areas.
c) The third method of dressing fixation included collars. This method was useful for a part
and kept the dressings in places for 48 hours in all cases, but the rabbits became very
agitated, didn’t feed and even some superficial neck lesions were present in some of
them. This type of dressing fixation didn’t allow them to destroy the dressing, but in a
small space like the cages, their movements were very much restricted.
d) The fourth method that we have used for dressing fixation was the raisin cast. First, a
circular cast with a narrow form to the feet and wider in the chest, for a good breathing,
was separated from the rabbits skin with some cotton, reducing this way the possibility of
hurting them. After the raisin became hard, the cast was cut and then fixed with tape
(Omnifix®, Hartmann) and retention bandages (peha haft, Hartmann). All the dressings
were intact after 48 hours. In 4 cases, the cast was a little too long, so there were pressure
sores at the knees’ level.
For the posterior legs, the dressings were fixed with skin circumferential retention bandages,
which in turn were fixed with skin staplers.
For all the burned area, to prevent wound drying and absorption of the used gels by the dressing,
we used Grassolind® (Hartmann) (paraffin gauze dressing).
III.
Evaluation of the topical effect of anabolic hormones on burned wounds
using hyaluronic acid and collagen type I as biomaterials
We used 4 groups of 20 New Zealand white male rabbits. On each animal we inflicted 4 burned
wounds- one on each flank and one on each posterior leg. The burns wounds were made with the
copper device heated in water according the aforementioned specifications. The burned wounds
on the left side were used as control and only the biomaterial gel was applied, while on the right
sided wounds, considered the study, a combination of anabolic hormones and biomaterials were
used to cover the wounds. All the study areas were visually inspected and photos taken at each
dressing. The topical treatment was applied in a gel form, with dressings every other day for two
weeks. Eight weeks later, skin biopsies were harvested from the burned areas for pathological
and immunohistological examination. The histology exam targeted vascularization, collagen
production and local inflammation.
For each rabbit, blood samples were taken to monitor the systemic effects of rGH and
oxandrolone respectively at the beginning of the study and after the topical treatment ended.
a) On the first group we applied the gel consisting of rGH and HA on the study (right) side
and the HA gel on the control side (left). On the study side a faster wound healing was
noticed. We proved that the site treated with the combination of HA and rGH had less
wound contraction, increased collagen production, vascularization than the control (HA
only). Serologic, no differences before and after topical administration of rGH have been
observed.
b) On the second group we used a combination of Oxandrolone and HA on the study side
and only HA on the control side. Visual evaluation of the burned areas demonstrated a
faster wound healing on the OX side. Also histology supported the clinical data – the
burned areas treated with the OX and HA combination showed reduced inflammation,
increased vascularization and reduced myofibroblast activity. The serology did not show
any significant systemic effects of topically administered Oxandrolone.
c) On the third group, the study side was treated with a gel containing Collagen type I and
rGh and the control side only with a Collagen type I gel. The wounds treated with
Collagen and rGh had significantly less wound contraction than their counterparts.
There were no evident systemic effects of rGH.
d) On the fourth group we applied Collagen type I and Oxandrolone gel on the study side
and only Collagen type I gel on the control side. The Oxandrolone side had faster healing
with less wound contraction. The serology did not show any significant systemic effects
of topically administred Oxandrolone.