الفهرس 
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Abstract
The aim of this work was to evaluate the role of platelet rich plasma and colchicine in healing of experimentally induced skeletal muscle ischemia/reperfusion injury in adult male albino rats. This work was carried out on 90 adult male albino rats. Ten rats were used for blood extraction & preparation of platelet rich plasma via cardiac puncture after being anesthetized by inhalation of 2% isoflurane. Eighty rats were used and divided equally into 4 groups: group I (Control group): It was subdivided equally into two subgroups: Subgroup Ia (negative control): They were left without any manipulation or medication. Subgroup Ib (positive control): They were injected by 1ml saline solution intra peritoneal single dose. group II (Ischemia/reperfusion group): The hair over the gastrocnemius muscle was shaved. They were subjected to lower limb ischemia by application of tight elastic rubber tourniquet as high as possible. It was applied around the right hind limb of the rats and maintained for 3 hours. Ischemia was observed by blue discoloration of rat hind limb distal to tourniquet. Reperfusion was allowed by releasing the tourniquet and confirmed by returning the color of the extremity to normal. Summary and Conclusions 152 This group was subdivided into two equal subgroups: Subgroup IIa: In which muscle specimens were obtained 2h after reperfusion. Subgroup IIb: In which muscle specimens were obtained on the 7th day after ischemia/reperfusion injury. group III (PRP treated): They were subjected to hind limb ischemia as group II then injected with 0.1 ml of platelet rich plasma given intramuscular in right gastrocnemius immediately within the onset of reperfusion process (after 3 h of ischemia). This group was subdivided equally into two subgroups: Subgroup IIIa: In which muscle specimens were obtained 2h after reperfusion. Subgroup IIIb: In which muscle specimens were obtained on the 7th day after ischemia/reperfusion injury. group IV (Colchicine administration just prior to ischemia/reperfusion injury): They were injected intra peritoneal with (1 mg/kg) of colchicine (single dose) just before subjected to injury as done in-group II. This group was subdivided equally into two subgroups: Subgroup IVa: In which muscle specimens were obtained 2h after reperfusion. Summary and Conclusion 153 Subgroup IVb: In which muscle specimens were obtained on the 7th day after ischemia/reperfusion injury. Rats in all groups were sacrificed at the optimal time 2h and 7days after ischemia/reperfusion injury. Muscle specimens from right gastrocnemius muscle were obtained and prepared for histological and immunohistochemical examinations. Data were analyzed as mean ± SD and P value was calculated. Results: 1.Histological results group I (Control): Examination of this group revealed normal histological structure of skeletal muscle. group II (Ischamia/reperfusion injury): Light microscopic examination of subgroup IIa showed ballooned muscle fibers, some fibers were fragmented with loss of myofibrils and others showed pale degenerative areas. Wide separation of skeletal myocytes with inflammatory cellular infiltrations and hemorrhage in perimysium. Sarcolemma was irregular and muscle fibers appeared wavy with crowded and pyknotic nuclei. Subgroup IIb showed area of muscle degeneration and area of regeneration. Appearance of few muscle fibers of variable size with central nuclei and some muscle fibers were fragmented with wide separation between skeletal myocytes. Summary and Conclusions 154 Mallory trichome stained sections of subgroup IIa showed moderate increase in collagen fibers in-between muscle fibers which markedly increased in subgroup IIb after 7 days. group III (PRP treated group): Light microscopic examination of subgroup IIIa showed nearly the same findings which were observed in subgroup IIa in the form of necrosis of some muscle fibers and inflammatory cellular infiltrations. Fat droplet deposition was noted in perimysium. Muscle fibers showed marked discontinuity and sarcolemma appeared wavy with pyknotic nuclei. Loss of normal transverse striation and intercellular spaces were wide. Subgroup IIIb showed excessive formation of regenerated muscle fibers with central pale nuclei forming myotubes. Mallory trichome stained sections showed decrease amount of collagen fibers as compared to group II. group IV (Colchicine treated group): Light microscopic examination of subgroup IVa showed fragmentation of the sarcoplasm and endomysium appeared wide in some areas. Some muscle fibers showed partial distortion of the polygonal shape and others appeared normal as compared to control. Subgroup IVb showed polygonal muscle fibers with acidophilic sarcoplasm and peripherally located nuclei. Some muscle fibers appeared with central nuclei. Mallory trichome stained sections showed minimal amount of collagen in-between muscle fibers. Summary and Conclusion 155 2. Immunohistochemical results group I (Control): CD34 immunostained sections of group I showed negative reactivity in the endothelial cells of blood vessels. Myogenin immunostained sections of group I showed negative nuclear reactivity to myogenin. group II (Untreated group): New vessels formation were detected by anti CD34 in subgroup IIb, while in subgroup IIa showed negative reactivity in the endothelial cells of blood vessels. Myogenin immunostained sections of subgroup IIa and subgroup IIb showed positive nuclear reactivity detected in some satellite cells under the sarcolemma of degenerated skeletal muscle fibers and of regenerating skeletal muscle fibers respectively. group III (PRP treated group): CD34 immunostained sections of subgroup IIIa showed negative reactivity in the endothelial cells of blood vessels, while new vessels formation were detected by anti CD34 in subgroup IIIb. Myogenin immunostained sections of subgroup IIIa showed more positive nuclear reactivity detected in many satellite cells when compared to subgroup IIa. Sections of subgroup IIIb stained with myogenin antibody showed marked positive nuclear reactivity when compared to subgroup IIb. Summary and Conclusions 156 group IV (Colchicine treated group): CD34 immunostained sections of subgroups IVa and IVb showed negative reactivity in the endothelial cells of blood vessels. Few satellite cells could be detected by myogenin antibody in both subgroups IVa and IVb. 3. Morphometric and statistical analysis results: As regards to the number of centrally nucleated myofibers, a highly significant increase was noted at day 7 in PRP treated group when compared to other groups at the same periods. Regarding the area percentage of the collagen fibers 2 hours after IRI, a highly significant increase was noted in untreated group when compared to other groups at the same period. Also, after 7 days, highly significant increase was observed in untreated group when compared to PRP treated, colchicine and control ones. However, non-significant difference was observed in colchicine group when compared to control. The number of blood vessels 2 hours after IRI showed a highly significant reduction in all experimental groups when compared to control. On the other hand, the number of blood vessels after 7 days showed a highly significant increase in PRP treated group when compared to control, untreated and colchicine groups. The number of myogenin immunopositive cells after 2h showed highly significant increase in untreated group when compared to control. Also, highly significant increase was noted in PRP treated when compared to untreated and colchicine groups. Summary and Conclusion 157 After 7 days, the number of myogenin immunopositive cells showed highly significant increase in PRP treated when compared to control, untreated and colchicine groups.