الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
Ulcerative colitis (UC) is referred as one of the inflammatory bowel diseases (IBD) that results in inflammation and ulcers of the colon and rectum. It is associated with life-long and recurrent disorders of the gastrointestinal tract. The main clinical symptoms of ulcerative colitis involve recurrent attacks and relapses of lower abdominal pain, diarrhea, purulent stools, weight loss, nausea, vomiting, arthritis and mouth sores.
Mesenchymal stem cells (MSCs) are multipotent progenitor cells that have the ability of self-renewal while maintaining their multipotency. They can also differentiate into various cells under certain conditions. Therefore, MSCs may be involved in tissue regeneration and might contribute to specific therapeutic effects. Among the different types of stem cells, bone marrow-derived MSCs (BM-MSCs) have gained great popularity as they can be easily isolated and expanded in vitro.
Vitamin E is a potent lipid soluble antioxidant vitamin. It may prevent the increase of reactive oxygen species (ROS) produced by oxidative damage of lipids in cellular components and tissues. Vitamin E may be expected to reduce injury and/or improve tissue after injury from ulcerative colitis.
The aim of this study is to explore the possible therapeutic effect of mesenchymal stem cells and vitamin E on experimentally induced ulcerative colitis in adult male albino rats.
This work was carried out on 60 adult male albino rats that were divided into the following five groups:
group I (Control group):
It included 20 rats that were further subdivided into four subgroups:
• Subgroup A: (included 5 rats) that were kept without treatment for the same periods as experimental animals.
• Subgroup B: (included 5 rats) that received a single intra-rectal injection of 2 ml physiologic saline.
• Subgroup C: (included 5 rats) that received 1 ml sunflower oil (the dissolving vehicle for vitamin E) three times in a week through gastric gavage.
• Subgroup D: (included 5 rats) that received a single injection of phosphate buffer saline (PBS) intravenously (i.v.) via tail vein.
group II (Ulcerative Colitis group):
It included 10 rats that received a single intra-rectal injection of 2 ml of 3% acetic acid.
group III (vitamin E group):
It included 10 rats which were given vitamin E orally 24 hours after a single intra-rectal injection of 2 ml of 3% acetic acid for induction of ulcerative colitis. vitamin E was given three times in a week (every other day) in a dose (100 mg/kg body weight) by gastric gavage.
group IV (BM-MSC group):
It included 10 rats which were treated with a single injection of bone marrow derived mesenchymal stem cells (BM-MSCs) 5×105 cells/150 μl in Phosphate buffered saline via tail vein, 24 hours after induction of ulcerative colitis with a single intra-rectal injection of 2 ml of 3% acetic acid.
group V (BM-MSC and vitamin E group):
It included 10 rats which were treated with both vitamin E orally (in a dose 100 mg/kg body weight) three times in a week (every other day) and BM-MSCs (5×105 cells/150 μl) in Phosphate buffered saline via tail vein, 24 hours after induction of UC with a single intra-rectal injection of 2 ml of 3% acetic acid.
Animals were anesthetized on 8th day with ether and the abdominal wall was opened exposing the viscera. The distal 3 cm of the colon was removed rapidly, prepared, processed and stained for examination by both light and electron microscopes.
The specimens were subjected to the following:
I. Haematoxylin and Eosin (H&E): used for the study of general histological features.
II. Periodic Acid Schiff reaction (PAS): to demonstrate the neutral mucopolysaccharides.
III. Immunohistochemical staining for proliferating cellular nuclear antigen (PCNA): Its level correlates directly with rates of cellular proliferation and DNA synthesis.
IV. Immunohistochemical staining for cyclooxygenase 2 (COX-2): which is associated with the mediation of inflammation.
V. Immunohistochemical staining for factor VIII: which is a marker to identify endothelial cells.
VI. Semithin and ultrathin sections for electron microscopic study: Uranyle acetate and lead citrate stains were used to stain ultrathin sections for transmission electron microscopic study.
Results :
• group I (Control group):
Control rats showed the normal histological structure of the rat colon that was studied and described in detail using light and electron microscopes. The mucosa exhibited regularly arranged, closely related crypts. Simple columnar cells and many goblet cells lined the mucosa and the crypts. There was no plicae nor villi.
• group II (Ulcerative Colitis group):
The light microscopic examination revealed areas of ulceration, disturbed crypt architecture, cellular infiltrations in between the crypts and dilated congested blood capillaries with extravasated RBCs. Sections showed very few PAS +ve mucin secreting cells with nearly complete depletion of goblet cells of surface epithelium and crypts, which was confirmed with a significant decrease in the mean number of goblet cells when compared with the control group. Immunohistochemical studies revealed significant decrease in the mean number of PCNA immunoreactive cells, a significant increase in both the COX-2 expression and the mean vascular density of +ve immunostaining to factor VIII compared to control group.
The ultrastructural examination of UC group revealed disrupted colonocytes with marked reduction in number of microvilli, widening of intercellular space and loss of junction complex. Pyknotic crypt cells and degenerated goblet cell were also seen. The lamina propria with infiltration by many inflammatory cells as lymphocytes and eosinophils, with marked loss of collagen fibers.
• group III (vitamin E group):
The light microscopic examination revealed areas of erosion of surface columnar epithelial lining and cellular infiltrations in between the crypts. The mucosa and the crypts were lined by few PAS +ve mucin secreting goblet cells that was confirmed by the significant decrease in mean number goblet cells versus the control group. The immunohistochemical studies revealed significant decrease in the number of PCNA immunoreactive cells, a significant increase in both the COX-2 expression and number of blood vessels with +ve immunostaining to factor VIII versus the control group.
The ultrastructural examination showed areas of marked reduction of microvilli, widening of intercellular space and disrupted junctions. Goblet cells had dilated rER. The lamina propria was infiltrated by eosinophils, lymphocytes and mast cells with numerous lytic areas of collagen and dilated blood capillaries.
• group IV (BM-MSC group):
The light microscopic examination revealed improvement in the morphological changes observed in the previous two groups in the form of apparently normal intact surface columnar cells with adjacent areas of stratification. Some mucosal crypts were intact and were spaced by little inflammatory cell infiltration. The mucosa and the crypts were lined by numerous mucin secreting cells confirmed with a significant increase in the intensity of PAS +ve reaction compared to UC group. On the other hand, few crypts showed –ve PAS reaction. The immunohistochemical studies revealed significant increase in the number of PCNA immunoreactive cells, significant decrease in the both COX-2 expression and number of blood vessels with +ve immunostaining to factor VIII versus UC group.
The ultrastructural examination of this group showed intact mucosal lining surface epithelium with continues microvilli and regularly arranged mucosal crypts. A giant secondary lysosome and areas of stratification of epithelium with widening in intercellular space were seen. Lamina propria had regularly arranged collagen fibers between fibroblasts.
• group V (BM-MSC and vitamin E group):
Compared with the previous groups, there was more pronounced improvement shown in the form of intact mucosal lining and crypts seen by light microscopic examination. The crypts were lined mainly by goblet cells and a strong PAS +ve reaction, similar to control group, that was confirmed statistically by the significant increase in mean number of goblet cells in comparison to UC group. The crypts were spaced by normal looking lamina propria. The immunohistochemical studies revealed a significant increase in the number of PCNA immunoreactive cells, significant decrease in both the COX-2 expression and number of blood vessels with +ve immunostaining to factor VIII when compared to UC group.
The ultrastructural examination of this group showed normal ultrastructure colonic epithelium, regularly arranged crypts spaced by normal lamina propria with regularly organized collagen fibers around fibroblasts and normal blood vessels.