Abstract In order to study the possibility of repairing bone defect by cryopreserved vascularized bone allograft, 8 dogs were divided into 2 groups. In the experimental group, 15% dimethylsulfoxide (DMSO) was used as a cryoprotective agent, the posterior segments of dog s rib, pedicled with intercostal vesseles, were cryopreserved by a two-step freezing procedure,stored in liquid nitrogen for 96 hours, and then transplanted as allografts to theiliac bone defects of recipients by vascular anastomosis. In the control group, the autografts were transplanted in the same procedure. Immunosuppersive agents were administrated postoperatively for 3 weeks. The specimens were analyzed by immune response monitoring (IL-2, T cell subsets), SPECT scanning, angiography and pathologic examination. The results showed that the allografts had good blood supply and active osteocyte metabolism, bone healing of the allografts was perfect at 3 months and no evidence of immunologic rejection. The process of bone healing of allografts should be further investigated.
OBJECTIVE:To investigate the index of the rejection of lJle retinal pigment epithelium(RPE)cells transplantation. METHOD:Allogenic RPE transplantation on rahbits by transcleral technique, the changes of interleukin-2 (IL-2) activity in peripheral blood and the effect of immunoinhibitor (methylprednisonlone)were detected. RESLILTS:In the group of simple transplantation,the IL-2 activity in peripheral blood begin to rise in the first day after operation. The peak value occured in the third day,and is still much higher than that of the control group in the 14th day,whereas in the group treated with immunoinhibitor ,there was no obvious difference in the first day after operatlon,in the third day,the IL-2 activity rises slightly,and returned to normal level in the 7th day. CONCLUSION: After RPE transplantation, the level of IL-2 activity in peripheral blood might serve as an important index to determining and detecting the rejective response. （Chin J Ocul Fundus Dis,1996,12: 239-241）
OBJECTIVE To prevent early closure of growth plate and developmental deformities of limbs by allografts of cultured cartilages into growth plate defects of rabbits. METHODS Chondrocytes isolated from articular cartilage of 1-month rabbits formed cartilage after cultivation in centrifuge tubes. The cartilages cultured for two weeks were implanted into growth plate defects of proximal tibiae of 6-weeks rabbits. At 4th and 16th weeks, X-ray, histologic and immunohistochemical examination were performed. RESULTS The tibiae had no marked deformities after 4 weeks of operation. Histologic examinations showed that the defects were filled with cartilage. Immunohistochemical results of type II collagen were positive. The tibiae with allografts of cultured cartilages had no evident deformities after 16 weeks of operation. Histologic examination showed nearly closure of growth plates. On the contrary, the tibiae on control side formed severe deformities and growth plate were closed. CONCLUSION Allograft of cultured cartilages into growth plate defects may replace lost growth plate tissues, maintain normal growth of limbs and prevent developmental deformity.
Objective To review the methods of overcoming immunological rejection in xenotransplantation.Methods The strategies of overcoming immunological rejection in xenotransplantation were analyzed and summaried on the basis of an extensive review of the latest l iterature concerned. Results The research development of immunological rejection mechanism and molecular biological technique provided new approaches for overcoming immunological rejection in xenotransplantation. Conclusion It is only a matter of time for xenotransplantation to be appl ied cl inically.
Objective To study the effect of transforming growth factor β1 (TGF-β1) plasmid on poly frosted-defrosted allogenic nerve transplantation. Methods Forty Wistar rats were randomly divided into two groups equally. A 2.0 cm sciatic nerve segment, 5 mm away from infrapiriformis muscle space, was removed and the defect was repaired with poly frosteddefrosted allogenic nerve. The TGF-β1 plasmids were injected into the nerve anastomosis and adjacent muscles in the experimental group, normal saline in the control group. The nerve specimens were sectioned for staining in the 6th and 12th weeks . Axonal count and statistical analyses were done. Results The grafted and distal nerve segments showed regenerated fibers in both groups. In the experimental group,less edema and more nerve fibers were observed in the 6th week. The grafted nerve segment was filled with regeneration axons, the myelinated nerve fibers arranged regularly, and the axons and the myelin sheaths developed well in the 12th week. There was significant difference in the number of regenerating axons between the experimental group 98.6±4.8／μm2 and control group 75.8±5.1／μm2 (Plt;0.01). Conclusion Multiple frost-defrost of allogenic nerve can reduce its antigenicity and increase itsusefulness in repairing nerve defects. Local use of TGF-β1 plasmid can enhance immunosuppression to reduce immuno rejection.
OBJECTIVE To investigate the mechanism of xenotransplantation rejection and the interaction between the immunocytes. METHODS: This review concluded the research achievements and new advances in xenotransplantation based on the relevant experimental data. RESULTS: Transgenic pig technology and novel immunosuppressants were applied to suppress hyperacute rejection and acute vascular rejection respectively. Modulation of T cell and antigen presenting cells and induction of tolerance were taken for the prevention of acute cellular rejection. CONCLUSION: In general, the technology of transgenic pig is relatively mature and effective. The mechanism and prevention of acute vascular rejection and acute cellular rejection should be further investigated.
Objective To evaluate the clinical effects of fibula flap grafts on the repair of the extremities with traumatic compound tissue defects. Methods In 12 cases, the fibula flap grafts were employed to restore the extremities with traumatic compound tissue defects. Of the 12 patients, 9 were males, 3 were females; their ages ranged from 12 to 45. There were 2 cases of tibia defect combined with fibula fracture, 2 cases of tibia defect, 2 cases of radius defect, 3 cases of ulna defect, 1 case of calcaneus defect,and 2 cases of firstmetatarsus defect. The bone defect length ranged from 4.2 to 10.6 cm, 7.8 cm in average.The skin defect area ranged from 10.0 cm×4.5 cm to 27.0 cm×15.0 cm. The free transplantation of fibular flaps were used in 9 cases, the lapse operation were used in 2 cases, retrograde shift were used in 1 case. Results Postoperational vein crisis and commonperoneal nerve traction injury were observed in category mentioned above respectively. All the 12 fibula flaps survived after proper treatments such as removalof great saphenous vein. Follow-ups were done for 6 to 24 months. Both the transferred fibula and the recipient broken end reflected bones were healed. Four patients underwent the second-phase reconstruction operation oftendon moving power. One wrist and 1 ankle underwent arthrodesis in 3 to 6 months.All the effects were satisfactory. Conclusion The fibula flap grafts provide arelatively better alternative to repair the extremities with long bone compoundtissue defects. In addition, the sensory function reconstruction of fibula flaps should be given full attention.
Objective To investigate the myogenic differentiation of mesenchymal stem cells (MSCs) after being transplanted into the local muscle tissues. Methods The serious muscleinjured model was established by the way of radiation injury, incising, and freezing injury in 36 mouses. Purified MSCs derived from bone marrow of male mouse and MSCs induced by5-azacytidine(5-Aza-CR) were transplanted into the local of normal muscle tissues and injured muscle tissues of femal mouse. The quantity of MSCs and the myogenic differentiation of implanted MSCs were detected by the method of double labeling, which included fluorescence in situ DNA hybridization (FISH) and immuno-histochemistry on the 1st, 3rd, 6th, 9th, 12th, and 15th day after transplantation. Results The quantity of implanted MSCs decreased as timepassed. MSCs’ differentiation into myoblasts and positive expression of desmin were observed on the 15th day in purified MSCs group and on the 6th day in induced MSCs groups. Conclusion MSCs could differentiate into myoblasts after being implanted into the local of muscle tissues. The differentiationoccurs earlier in the induced MSCs group than that in purified MSCs group.
OBJECTIVE To explore the healing mechanism of full-thickness wound treating by the intermingled skin transplantation of large sheet allograft with autograft through studying the expression of laminin (LN). METHODS Thirty-six SD rats with 10% to 15% of total body surface area (TBSA) full-thickness were made. After 3 days, the devitalized tissue were excised and transplanted a large sheet of allograft from Wistar rats and islets of autografts were implanted 3 days later. On day 3, 5, 7, 14, 21 after allografting, the expression of LN in the grafts were detected by immunohistochemistry. RESULTS On the 7th day postallografting, LN, which played positive action of epidermal cell adhesion, still retained in the allodermis after the rejection of alloepidermis occurred. On the 14th day postallografting, there appeared scattered LN underneath the epidermal cells migrating from islets of autografts. On the 21st day postallografting, LN in the basement membrane of skin grafts had completely formed. CONCLUSION The intermingled transplantation of large sheet allograft with autograft may provide components of basement membrane for wound healing, which may help to improve the appearance and function of skin.
PURPOSE:To investigate the approaches for transplanting retinal pigment epithelium. METHODS,Retinal pigment epithelial eells(RPR)of pigmented rabbits' eyes prepared by rotalne preparation of our institute,were transphmted in 18 unpigmemed rabbits'eyes.Eight eyes were undergone outer approach, i.e., transplanting the RPR cells to the subretinal space of recipient eyes by way of perforating sclera and choroid;while 10 eyes were undergone internal approach by way of the routine procedure of vitrectomy with making artificial localized retinal delachment. Light and transmisskm electrone microscopy examination were done at 10th, goth, 40th and 90th day after the operation. RESULTS: In internal approach group,tbe operated eyes,revealed no difference in thickness of the neural retinal layer in transplanted and non-transplanted area 40 days after operation tinder light microscope. Transmission electrone microscopy revealed postoperatively the transplanted RPE cells attached to the Brucb's membrane and the outer segments of photoreeeplive ceils located at a normal position at the 40th dayland the secondary lysozymes with engulfed outer segment were found in the Iransplamed cells at the 90th day. Tbe outer approached operations in eight eyes were failed owing to ehoroid hemorrhage or perforation of retina. CONCLUSION:The internal appraach procedure is much effebtive and practical for transplantation of RPE cells. （Chin J Ocul Fundus Dis,1997,13:160-162）