الفهرس 
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Abstract
This study was conducted to investigate and evaluate histologically the
effect of local application of Simvastatin drug in gel form on healing of
mandibular fractures in experimentally induced diabetic rats.
The study was conducted on twelve healthy adult male Sprague-
Dawley rats weighed between 150-200 grams. Diabetes induction in all rats
achieved by intraperitoneal injection of a single dose of STZ 60mg/kg body
weight which should be freshly prepared following twelve hours fasting,
Their blood glucose levels were tested after 72 hours of the administration of
Streptozotocin and every three days throughout the time of the experiment by
blood drops obtained from tail vein.
Two weeks following STZ injection, the surgical operation was
performed on each rat, where unilateral extra oral submandibular incision at
the right side was done then vertical mandibular fracture was created at the
posterior third of the mandible. In group 1 (the control one), SMV gel was not
injected at the fracture site. Whereas, in group 2 (the study group); about 2.5
mg of Simvastatin gel was applied locally at the fracture site. Postoperative
response and healing were observed, blood glucose levels were recorded. No
abnormal immunologic response at the surgical site of the study group was
noticed, indicating the good tolerance and biological safety of the local
application of the Simvastatin drug.
Rats were divided into three groups according to the time of
scarification: at 1, 4 and 8 weeks following the surgical operation. Each group
consists of 4 rats (2 controls and 2 studies). Histological examination of the
fractured part of the mandible was carried out to both study and control groups.
As early as one week post-surgical, in the control group the fractured
area was filled with granulation tissue, fine and dense collagen fibers which
are randomly oriented, fibroblasts and inflammatory cells. While in the study
group the experimental area was filled with fibrovascular tissue composed
mainly of thick collagen bundles which were arranged in a more order
manner, deeply stained proliferating fibroblasts and marked reduction in
inflammatory cells and greater vascularity.
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Four weeks post-surgically; bone formation was manifested in the
control group by presence of islands of boney specules which were less in
amount as compared to the study group, where the gap was invaded by
bridges of thick lamellated bone which is more mature rimmed by active
osteoblasts and smaller marrow spaces.
Eight weeks following the surgical operation, the control group showed
the newly formed bone with marrow spaces in between and defects in
mineralization, while in the study group the new bone was visible, bridged
nearly all the gap area and in direct contact with the old bone surface,
appeared together as one unit.