الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Summary
Psoriasis is a chronic, non-communicable, immune-mediated inflammatory skin disease involving mainly tissues of skin and joints. The main microscopic abnormalities of psoriasis include abnormal epidermal cells differentiation, proliferation, angiogenesis, and increased T-cell infiltration. Imiquimod (IMQ) is a toll-like receptor agonist drug that has been used as a standard model in the induction of psoriasis in experimental studies. Psoriasis remains one of the diseases without known causes and no standard known treatment. Bone marrow-derived mesenchymal stem cells (BM-MSC) were found to have significant immunomodulatory properties in many diseases. However, Stem cells carry the potential risk of transformation with prolonged in vitro cultivation. Thus, according to the paracrine hypothesis, the beneficial effects of stem cell therapy are attributed to stimulation of resident cells by secretion of bioactive molecules and release of extracellular vesicles including the exosomes. Thus, a large scale of research is being conducted to investigate the role of exosomes in various diseases in different tissues.
Summary and Conclusion
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In the present study, fifty adult albino rats (40 females and 10 males) of average weight 150 – 200 grams were used. They were classified into four main groups:
group (I) – Control group:
Ten female albino rats were subdivided into two subgroups:
• Subgroup Ia: Five rats were left without treatment and served as a negative control group.
• Subgroup Ib: Five rats were injected subcutaneously with an equivalent volume of Phosphate Buffer Saline (PBS).
group (II) – Imiquimod group:
Ten female albino rats were subjected to topical imiquimod cream to induce psoriasis-like skin inflammation. The cream was applied once daily (62.5 mg, 5% cream) on a shaved part of the skin of the back (area of 2 x 2 cm) for 5 consecutive days.
group (III) – Imiquimod and BM-MSCs group:
Ten female albino rats were subjected to topical imiquimod cream for five days as in group II concomitant with
Summary and Conclusion
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a single subcutaneous injection of 1 million BMSCs in 1 ml PBS on the first day only.
group (IV) – Imiquimod and BM-MSCs derived exosomes group:
Ten female albino rats were subjected to topical imiquimod cream for five days as in group II concomitant with a single subcutaneous injection of purified exosome concentrate collected from the conditioned medium of 1 million BMSCs in 1ml PBS on the first day only.
Source of BM-MSCs and BMSCs derived exosomes:
Ten male albino rats were used as a source of mesenchymal stem cells and their derived exosomes. The stem cells were isolated and cultured from the bone marrow of the animals’ hind limbs.
Isolation and Culture of BM-MSCs:
Isolation and culture of BM-MSCs were performed in Stem Cells Research Unit, Histology and Cell Biology Department, Faculty of Medicine, Ain Shams University. According to Caplan’s method, ten male albino rats of average
Summary and Conclusion
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weight 100 grams were used to collect the bone marrow from both the tibia and femur.