الفهرس 
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Abstract
The present work aimed to compare the therapeutic effect of FBSsupplemented MSCs and PRP-supplemented MSCs on induced sciatic nerve crush injury in adult male albino rat. Seventy-five adult male albino rats weighting 180-200 grams were used in this study and equally divided into five main groups (15 each) as follows: • group I (Control group): this animal group was used for obtaining whole blood sample (for PRP separation), bone marrow (from both tibia and femur) and sciatic nerve control specimens. • group II (Sham group): in this group the animals were subjected to the same surgical procedures as group III (except for sciatic nerve injury) followed by intravenous injection of 0.5 ml culture medium. • group III (Sciatic nerve injury group): the animals were subjected to surgically- induced sciatic nerve crush injury. • group IV (Sciatic nerve injury + FBS-supplemented MSCs group): in this group the animals were subjected to surgically-induced sciatic nerve crush injury followed by a single intravenous injection of FBSsupplemented MSCs in 0.5 ml culture medium. • group V (Sciatic nerve injury + PRP-supplemented MSCs group): the animals were subjected to surgically- induced sciatic nerve crush injury followed by a single intravenous injection of PRP-supplemented MSCs suspended into 0.5 ml culture medium. At the end of the experiment (4 weeks after the surgery), sciatic nerve specimens were dissected for examination by light and electron microscope, then the animals were sacrificed. Masson’s trichrome stain was used for detection of collagen fiber and Toluidine blue stain was done to demonstrate myelin sheath. Morphometric study was done to measure collagen area % and g-ratio in all groups. The data were analyzed by performing one-way analysis of variance (ANOVA) test using statistical package for social sciences (SPSS) program. The results of this study were recorded and could be summarized as follows: 1- Control and sham groups: These groups were similar and showed the same histological picture which was identical to the known histological structure of sciatic nerve. It was studied and described in details using light and electron microscopes. 2-Sciatic nerve injury group: The light microscopic examination revealed many structural changes. H&E staining of L.S obtained from sciatic nerve in this group revealed disturbance in the normal structure in the form of disorientation, discontinuity and separation between the nerve fibers with focal mononuclear cellular inflammatory infiltration. While T.S of this group showed disorganization of almost all nerve fibers within the bundle with discontinuity of the perineurium and perivascular cellular infiltration. Some sections revealed loosely packed nerve fibers with loss of their normal histological structure and increased vascularity. Some nerve fibers exhibited peripherally located axons and discontinuous neurolemmalsheath. Apparent decrease in the number of nerve fibers and focally thickened irregular perineurium also seen in some sections. Inflammatory cells around blood vessels and fibroblast with elongated nuclei were detected in between the distorted nerve fibers. Masson’s trichrome stained L. S and T.S obtained from this group revealed apparent increase in collagen strands of epineurium, perineurium and delicate collagen fibers in endoneurium as well as around blood vessels, while toluidine blue stained sections revealed irregularly disorganized nerve fibers. In some sections nerve fibers appeared markedly thickened while others showed obliteration of the axoplasm (Honey comb appearance). Myelin sheath of other nerve fibers exhibited vaccuolation, splitting and whorls formation within its layers. As regards the electron microscopic examination, ultrastructural changes were observed. Some sections revealed irregularly disorganized nerve fibers with focal ballooning and vacuolation. As regards myelin sheath, it exhibited lysis, irregular wide separation and splitting, which was circumferential in some sections, while focal in others. Focal separation between myelin sheath and the axoplasm was observed in some sections, while others exhibited complete detachment of a part of myelin sheath into the axoplasm. Regarding axoplasm, it was apparently normal in some myelinated nerve fibers. Concerning Schwann cells, they exhibited dense bodies, vacuolation and rarefaction within their cytoplasm. Regarding the endoneurium, there was apparent increase in collagen fibrils and the inflammatory cells within the blood vessels. 3-Sciatic nerve injury with FBS-supplemented MSCs group: The light microscopic examination of H&E stained sections obtained from this group revealed minimal structural changes. L.S showed preservation and restoration of the normal structure of the nerve bundles with characteristic parallel, wavy pink nerve fibers. Schwann cells with ovoid nuclei, multiple dilated congested blood vessels and intact perineurium were noticed. Transverse sections in this group showed proper organization of the nerve fibers within the bundle and intact both epineurium and perineurium. Some sections revealed restoration of myelin sheath and axons, while residual vacuoles in few other nerve fibers were still present. Masson’s trichrome stained L.S and T.S obtained from this group revealed well organized nerve fibers with apparent decreased collagen strands in the epineurium, perineurium and endoneurium, while toluidine blue stained sections showed preservation and restoration of the normal histological structure of most of the nerve fibers with occasionally minimal changes. The fibers showed intact, thick and continuous myelin sheath. Groups of thinly myelinated nerve fibers were also seen in between the myelinated ones. The electron microscopic examination of this group revealed partial preservation of the ultrastructure of myelinated nerve fibers. Most of the myelinated nerve fibers exhibited intact, continuous, electron dense and tightly wrapped myelin sheaths, while some of them revealed focal splitting. The axoplasm of most nerve fibers was apparently normal, but few small vacuoles were observed in some other nerve axons. Regarding Schwann cells surrounding the myelinated nerve fibers were apparently normal regarding its cytoplasm and nucleus, while occasionally some of them revealed vacuolated cytoplasm. Few collagen fibrils were observed in the endoneurium surrounding the nerve fibers. 4-Sciatic nerve injury with PRP-supplemented MSCs group: The light microscopic study of H&E stained sections obtained from this group revealed marked preservation and restoration of the normal nerve structure. The L.S of sciatic nerve of this group revealed thick, closely packed, well oriented continuous nerve fibers. The T.S of this group revealed almost normal structure of the nerve fibers with their central axons and surrounding sheaths within the bundle, intact perineurium and few congested blood vessels also evidenced. Masson’s trichrome stained L.S and T.S obtained from this group revealed apparent decrease in collagen strands of perineurium and endoneurium, while toluidine blue stained sections obtained showed preservation and restoration of the normal histological structure of sciatic nerve fibers. The myelinated nerve fibers appeared normal regarding myelin thickness and regularity with thin myelinated nerve fibers among the myelinated groups. Electron microscopic examination of sections obtained from sciatic nerve of this group revealed marked preservation of its ultrastructural integrity. But few sections revealed small focal splitting areas within the myelin sheath. Morphometric results & statistical analysis: There was a significant increase in the mean area % of collagen in injury group as compared to control group. Both FBS-supplemented MSCs and PRPsupplemented MSCs groups showed significant decrease in the mean area % of collagen fibers but more significant decrease in PRP- supplemented MSCs group compared to group In sciatic nerve injury group, the g-ratio was significantly reduced compared with the control group, while no significant differences between both FBS-supplemented MSCs group (group IV) and PRP-supplemented MSCs group (group V) compared to the control group. Concerning group (IV & V) there is significant increase in g- ratio compared to group III.