الفهرس 
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Abstract
Ulcerative colitis is an inflammatory bowel disease that characterized by chronic and relapsing inflammation of the gastrointestinal tract. The exact etiology of the disease is still not fully elucidated, as many factors are contributed in the disease pathogenesis. Dysregulated immune response toward luminal bacteria that highly triggered by environmental factors in genetically susceptible individuals is the most accepted mechanism.
It has been reported by previous studies that dietary management may be an interesting alternative or complementary to drug therapy to prevent or induce remission in UC patients, if it proves to be effective without side effects. One of the attracted food type in this research field is polyunsaturated fatty acids (PUFA).
Polyunsaturated fatty acids (PUFA) can be classified into two major categories, namely ω-3 and ω-6, which are present as essential cellular components and possess diverse biofunctions. PUFAs are essential fatty acids that should be obtained from diet as the body could not synthesize them endogenously.
Pathogen-free adult male Swiss albino rats weighing 200±20g were acclimatized for 7 days and then separated into four groups each of ten rats.
group 1: control group,
group 2: DSS group, rats fed 5% (w/v) DSS in their drinking water for 8 days
group 3: FO/CO group, rats were given FO/CO mixture in ratio 2.5:1 for four weeks (0.5 ml of FO/CO mixture/day/rat) by oral gavage.
group 4: DSS + FO/CO group, rats were fed 5% (w/v) DSS as in group 2 then orally administrated FO/CO mixture as in group (3).
At the end of the experiment, the rats, which were food deprived for 24 h, were anesthetized by light ether. Thoracotomy, cardiac puncture and exsanguination were then performed. Blood samples were collected and serum were separated to determine alkaline phosphatase (ALP). A midline abdominal incision was performed in each animal and colon were collected terminally from rats in different groups and divided into four parts; the first part was used to determine the activity of myeloperoxidase enzyme (MPO), and levels of tumor necrosis factor α (TNF-α) and interleukin 10 (IL-10), the second part was used for molecular investigation of inducible nitric oxide synthase (iNOS) and nuclear factor kappa B (NF-κB). The third part was used in immunoblotting analysis of signal transducer and activator of transcription (STAT-3) and finally, fourth part was used to examine the histopathological alterations.
Induction with DSS caused significant increase in colonic activity of MPO, serum ALP activity and colonic TNF-α level with significant decrease in the colonic IL-10 level. In addition, level of STAT-3 protein and the transcript levels of NF-κB and iNOS genes were significantly increased in comparison with control group.
On the other hand, FO/CO administration showed statistically significant increase in the level of anti-inflammatory mediator IL-10 and decrease in pro-inflammatory mediators MPO, TNF-α, and iNOS with significant decrease in levels of transcription factors STAT-3 and NF-κB in comparing to the colitis group.
Colon tissues in DSS treatment group showed massive numbers of inflammatory cells infiltration in the mucosa and underlying submucosa. While, in Colitis + FO/CO group, colon tissues showed fewer inflammatory cells in the lamina propria of the mucosal layer.
Conclusion:
from the mentioned results, it is concluded that FO/CO oils in ratio (2.5:1) have anti-inflammatory effect through attenuating production of pro-inflammatory mediators and maintaining the integrity of the intestinal mucosa, possibly by inhibiting NF-kB and STAT-3 activation and amplifying level of anti-inflammatory cytokine IL-10.