ABSTRACT
The effects of tacrolimus postconditioning on protein-serine-threonine kinases (Akt) phosphorylation and apoptotic cell death in rats after spinal cord ischemia-reperfusion injury were investigated. Ninety male SD rats were randomly divided into sham operation group, ischemia-reperfusion group and tacrolimus postconditioning group. The model of spinal cord ischemia was established by means of catheterization through femoral artery and balloon dilatation. The spinal cord was reperfused 20 min after ischemia via removing saline out of balloon. The corresponding spinal cord segments were excised and determined for Akt activity in spinal cord tissue by using Western blotting at 5, 15, and 60 min after reperfusion respectively. Spinal cord tissue sections were stained immunohistochemically for detection of the phosphorylated Akt expression at 15 min after reperfusion. Flow cytometry was applied to assess apoptosis of neural cells, and dry-wet weights method was employed to measure water content in spinal cord tissue at 24 h after reperfusion. The results showed that the activities of Akt in tarcolimus postconditioning group were significantly higher than those in ischemia-reperfusion group at 5, 15, and 60 min after reperfusion (P<0.05, P<0.01). The Akt activities reached the peak at 15 min after reperfusion in ischemia-reperfusion group and tacrolimus postconditioning group. The percentage of apoptotic cells and water content in spinal cord tissue were significantly reduced (P<0.01) in tacrolimus postconditioning group as compared with those in ischemia-reperfusion group at 24 h after reperfusion. It is concluded that tacrolimus post-conditioning can increase Akt activity in spinal cord tissue of rats, inhibit apoptosis of neural cells as well as tissue edema, and thereby alleviate spinal cord ischemia-reperfusion injury.
Subject(s)
Animals , Male , Rats , Apoptosis , Immunosuppressive Agents , Pharmacology , Therapeutic Uses , Phosphorylation , Protein Serine-Threonine Kinases , Genetics , Metabolism , RNA, Messenger , Genetics , Metabolism , Rats, Sprague-Dawley , Reperfusion Injury , Drug Therapy , Metabolism , Spinal Cord , Metabolism , Pathology , Spinal Cord Ischemia , Drug Therapy , Metabolism , Tacrolimus , Pharmacology , Therapeutic Uses , Up-RegulationABSTRACT
The effects of tacrolimus postconditioning on protein-serine-threonine kinases (Akt) phosphorylation and apoptotic cell death in rats after spinal cord ischemia-reperfusion injury were investigated. Ninety male SD rats were randomly divided into sham operation group, ischemia-reperfusion group and tacrolimus postconditioning group. The model of spinal cord ischemia was established by means of catheterization through femoral artery and balloon dilatation. The spinal cord was reperfused 20 min after ischemia via removing saline out of balloon. The corresponding spinal cord segments were excised and determined for Akt activity in spinal cord tissue by using Western blotting at 5, 15, and 60 min after reperfusion respectively. Spinal cord tissue sections were stained immunohistochemically for detection of the phosphorylated Akt expression at 15 min after reperfusion. Flow cytometry was applied to assess apoptosis of neural cells, and dry-wet weights method was employed to measure water content in spinal cord tissue at 24 h after reperfusion. The results showed that the activities of Akt in tarcolimus postconditioning group were significantly higher than those in ischemia-reperfusion group at 5, 15, and 60 min after reperfusion (P<0.05, P<0.01). The Akt activities reached the peak at 15 min after reperfusion in ischemia-reperfusion group and tacrolimus postconditioning group. The percentage of apoptotic cells and water content in spinal cord tissue were significantly reduced (P<0.01) in tacrolimus postconditioning group as compared with those in ischemia-reperfusion group at 24 h after reperfusion. It is concluded that tacrolimus post-conditioning can increase Akt activity in spinal cord tissue of rats, inhibit apoptosis of neural cells as well as tissue edema, and thereby alleviate spinal cord ischemia-reperfusion injury.
ABSTRACT
<p><b>OBJECTIVE</b>To observe the effect of tissue engineered nerves in repairing peripheral nerve defects (about 1.5 cm in length) in rats to provide data for clinical application.</p><p><b>METHODS</b>Glycerinated sciatic nerves (2 cm in length) from 10 Sprague Dawley (SD) rats (aged 4 months) were used to prepare homologous dermal acellular matrix. Other 10 neonate SD rats (aged 5-7 days) were killed by neck dislocation. After removing the epineurium, the separated sciatic nerve tracts were cut into small pieces, then digested by 2.5 g/L trypsin and 625 U/ml collagenase and cultured in Dulbecco's modified Eagle's medium (DMEM) for 3 weeks. After proliferation, the Schwann cells (SCs) were identified and prepared for use. And other 40 female adult SD rats (weighing 200 g and aged 3 months) with sciatic nerve defects of 1.5 cm in length were randomly divided into four groups: the defects of 10 rats bridged with proliferated SCs and homologous dermal acellular matrix (the tissue engineered nerve group, Group A), 10 rats with no SCs but homologous dermal acellular matrix with internal scaffolds (Group B), 10 with autologous nerves (Group C), and the other 10 with nothing (the blank control group, Group D). The general status of the rats was observed, the wet weight of triceps muscle of calf was monitored, and the histological observation of the regenerated nerves were made at 12 weeks after operation.</p><p><b>RESULTS</b>The wounds of all 40 rats healed after operation and no death was found. No foot ulceration was found in Groups A, B and C, but 7 rats suffered from foot ulceration in Group D. The triceps muscles of calf were depauperated in the experimental sides in all the groups compared with the uninjured sides, which was much more obvious in Group D. The wet weight of triceps muscle of calf and nerve electrophysiologic monitoring showed no statistical difference between Group A and Group C, but statistical difference was found between Groups A and B and Groups B and D. And significant statistical difference was found between Group B and Group D. Obvious compound muscle (or motor) action potential (CMAP) could be evoked in Group A and Group C, but the evoked amplitude was very low in Group B and Group D. The axons of regenerated nerves penetrated through the whole graft in Group A and Group C, and partly penetrated through the graft in Group B, but did not penetrate in Group D. The two tips of the separated sciatic nerves of Groups A , B , and C were connected together, without formation of neuroma. But those of Group D were not connected together and neuroma formed in 6 rats.</p><p><b>CONCLUSIONS</b>Tissue engineered nerves can be used for repairing long defects of the peripheral nerves of rats and ideal repairing effects can be obtained.</p>
Subject(s)
Animals , Female , Rats , Animals, Newborn , Nerve Regeneration , Peripheral Nerve Injuries , Rats, Sprague-Dawley , Sciatic Nerve , Wounds and Injuries , Tissue Engineering , MethodsABSTRACT
Objective To investigate the effect of intra-articular carboxymethylated ehitosan(CM- CTS)injection on inducible nitric oxide synthase(iNOS)expression in cartilage at the early stage of os- teoarthfitis(OA).Methods Thirty-two white rabbits were underwent unilateral anterior cruciate ligament transection(ACLT)and were randomly divided into 4 groups 5 weeks after transection.Rabbits of group A re- ceived 0.3 ml of 2% high molecular weight CMCTS(H-CMCTS)once every two weeks.Rabbits in group B were treated using 2% low molecular weight(L-CMCTS)CMCTS at:the same intervals.Group C rabbits were injected intra-articularly with 0.3 ml of 1% sodium hyaluronate(Na-HA)once a week.Animals of group D were not injected.At sacrifice,11 weeks following surgery,the expression of iNOS in cartilages was analyzed by immunohistochemistry and reverse transcription-polymerase chain reaction(RT-PCR)methods.Results Both immunohistochemistry and RT-PCR showed that the level of iNOS expression of cartilage in CMCTS in- jection groups was lower than that in Na-HA injection group and the untreated group.There was no significant difference in iNOS expression between the two different molecular weight CMCTS injection groups. No signifi- cant difference of iNOS expression in cartilage was found between Na-HA injection group and the untreated group.Conclusion CMCTS suppresses iNOS expression in cartilage during the early stage of OA.Na-HA treatment has no effect on iNOS expression in cartilage.