الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 16 |  |  |
| | | from | 16 | | |
Abstract
Acute pancreatitis is a serious inflammatory disease
associated with auto-digestion of the gland. This work was
aimed to study the role of BM-MSCs as a therapeutic modality
in acute pancreatitis induced by L-arginine in rats. It was also
aimed to compare the efficacy of early versus late injection of
BM-MSCs in restoration of normal exocrine pancreatic
parenchyma. Sixty five adult male albino rats weighing 200-
250 gm were used in this study. In addition 10 male albino rats
weighing 80-100 gm and aging 3-6 weeks were used for
preparation of BM-MSCs.
The experimental animals were classified into three groups:
Group I (control group): this group consisted of fifteen
animals. It was further subdivided into three subgroups, 5 rats
each:
Subgroup ІA:
It included 5 male albino rats that were sacrificed after 24
hours from injection of equivalent dose of saline.
Subgroup ІB:
It included 5 male albino rats that were sacrificed after 72
hours from injection of equivalent dose of saline.
Summary
205
Subgroup ІC:
It included 5 male albino rats that were sacrificed after 2
weeks from injection of equivalent dose of saline.
Group ІІ: L-arginine induced pancreatitis group: It included
30 male albino rats in which acute pancreatitis was induced. It
was further subdivided into three subgroups, 10 rats each.
Subgroup ІІA:
It consisted of 10 rats which were allowed to live for 24
hours after the last injection of L-arginine.
Subgroup ІІB:
It included 10 rats which were allowed to live for 72
hours after the last injection of L-arginine
Subgroup ІІC:
It included 10 rats which were left for 2weeks after the
last injection of L-arginine for spontaneous healing of
pancreatitis.
Group ІІІ: Stem cells treated group: It included 20 male
albino rats in which acute pancreatitis was induced followed by
injection of cultured and labeled BM-MSCs in phosphate buffer
Summary
206
saline in rat tail vein. It was further subdivided into two
subgroups, 10 rats each.
Subgroup ІІІA:
It consisted of 10 rats which were injected with bone
marrow derived mesenchymal stem cells 24 hours after the last
injection of L-arginine. They were allowed to live for two
weeks.
Subgroup ІІІB:
It included 10 rats which were injected with bone marrow
derived mesenchymal stem cells 72 hours after the last injection
of L-arginine. They were allowed to live for two weeks.
One rat from each of subgroups IIIA and IIIB was
sacrificed after one week to ensure homing of BM-MSCs into
rat pancreas.
Blood sample were collected for laboratory serum
amylase then pancreatic specimens were obtained, fixed and
processed for histological study. Other small pieces of
pancreatic tissues (1mm³) were freshly cut and fixed
immediately in buffered formol glutaraldehyde (pH 7.3).
Semithin sections were prepared and stained with toluidine
blue.
Summary
207
Morphometric studies were done for area percentage of
collagen fibers using Maisson’s trichrome stained sections and
PCNA positive cells number using immunoperoxidase stained
sections for PCNA using an image analyzer. Statistical analysis
was done for evaluation of the morphometric data and level of
pancreatic serum amylase using SPSS.17 program.
Serum amylase showed elevated level in subgroup IIA.
This level was decreased in subgroup IIB and returned to near
control group value in spontaneous healing group (subgroup
IIC). Also the value was near to control group in both early
BM-MSCs injection (subgroup IIIA) and late BM-MSCs
injection (subgroup IIIB).
On light microscopic examination of H&E and toluidine
blue stained sections, subgroup IIA showed focal structural
changes in some lobules as well as interlobular and intralobular
connective tissue. The affected acinar cells showed variable
structural changes. Some acinar cells were lightly stained.
Others showed vacuolated cytoplasm with pyknotic nuclei.
Zymogen granules depletion was obvious in some of them.
Areas of intense mononuclear cellular infiltration and oedema
were also noticed. The interlobular and intralobular connective
tissues were relatively thickened. Some blood vessels showed
Summary
208
fibrin clots with margination and pavementation of
inflammatory cells.
Subgroup IIB revealed more noticeable structural
changes than subgroup IIA. These changes extended to include
wide areas of pancreatic lobules. Intense periacinar
mononuclear cellular infiltration was detected with prominent
duct system within the pancreatic lobule. Interestingly,
subgroup IIC revealed loss of the normal lobulation of the
pancrease. Large areas of pancreatic parenchyma were occupied
by fat cells with noticeable areas of fat necrosis. Some intact
acini were seen in between fat tissue. Meanwhile, the remaining
acini appeared distorted, vacuolated with decrease in apical
secretory granules. Rounded structures of variable size were
detected which might be regenerating acini.
The striking feature which was observed in subgroups
IIA, IIB and IIC was the preservation of islets of Langerhans.
They appeared nearly similar to control group. The surrounding
pancreatic acini appeared intact and comparable to the control.
In stem cells treated group, subgroup IIIA, showed
normal structure with tightly packed pancreatic acini and thin
interlobular septa. Most acini were formed of normal acinar
cells with basal basophilia and apical secretory granules and
vesicular nuclei. Few acini showed hyalinized cytoplasm.
Summary
209
Meanwhile, in subgroup IIIB noticeable areas of pancreatic
affection were still present. There were focal areas of
disorganized acini. Localized areas of mononuclear cellular
infiltration were still noticed.
In Maisson’s trichrome stained sections showed
progressive increase of collagen fibers deposition in all
subgroups of group II to be maximum in subgroup IIC. In the
treated group, collagen fibers were still noticed surrounding the
acini and blood vessels in both subgroups but they were more
pronounced in subgroup IIIB. Despite of that, collagen fibers
were apparently less than those in subgroup IIC. These results
were confirmed by the statistical study.
Morphometric and statistical study for area percentage of
collagen fibers revealed significant increase in subgroup IIC in
relation to other subgroups. In the treated group (subgroup
IIIA and IIIB) there was a significant increase as compared to
the control. However they showed significant decrease as
compared to subgroup IIC.
PCNA stained sections revealed minimal reaction in
nuclei of acinar cells in subgroups IIA and IIB. However
moderate reaction was noticed in both the nuclei of acinar cells
and the rounded structures in subgroup IIC. Positive reaction
was distinguished in most of acinar cells nuclei in subgroups
Summary
210
IIIA and IIIB. Morphometric and statistical study for number
of PCNA positive cells revealed significant elevation in
subgroups IIIA and IIIB in comparison to other subgroups.