ABSTRACT
Objective To investigate curative effects of hypothermia on the secondary axotomy of nondisruptive axonal injury (NDAI) after diffuse brain injury (DBI).Methods A total of 16 male Sprague-Dawley rats were randomly and equally divided into hypothermia group (at 32℃ for 6 hours) and control group (at 37.5℃ ).The axonal swelling and axonal balls were detected by means of NF68kD immunochemistry after DBI caused by fluid percussion.The changes of maximal density of axonal swelling and axonal balls in callosum,diencephalon-mesencephalon,pons-oblongata and cerebellum were compared 24 and 72 hours after injury between both groups.Results NF68kD immunochemistry well showed axonal swellings and axonal balls in whole brain.The axonal swelling and axonal balls were significantly decreased 24 hours after DBI in both groups (P<0.05),especially in diencephalon-mesencephalon ,pons-oblongata and cerebellum (P<0.01).While there showed significant decrease of axonal swellings and axonal balls in pons-oblongata and cerebellum in hypothermia group 72 hours after DBI (P<0.05,P<0.01) but insignificant changes in the callosum and the diencephalon-mesencephalon compared with control group (P>0.05 ).Conclusions Hypothermia can retard the progress of mild or severe NDAI at early stage,which would taper with the longer time after injury except for partial mild NDAI.Hypothermia may prevent mild NDAI from secondary axotomy.
ABSTRACT
BACKGROUND:As a kind of undifferentiated precursor cells,the phenotypic differentiation of bone marrow mesenchymal stem cells (BMSCs) remains immaturity,thus it presents weak rejection following transplantation.However,the in vitro directional differentiation of BMSCs into neuronal cells is easy affected by various factors.OBJECTIVE:To observe the immunomodulatory effect and the potential of BMSCs differentiate into neuronal-like cells.DESIGN,TIME AND SETTING:A contrast observation was conducted at the Department of Cytology,Third People's Hospital of Wuxi from January 2008 to March 2009.MATERIALS:Bone marrow was harvested from chips of cancellous or ilium bone dudng hip joint surgery.METHODS:Firstly,the BMSCs were separated and cultured to establish mixed lymphocyte reaction (MLR) system.Secondly,2 samples of peripheral blood mononuclear cells (1×10~5/well) were added into 96-well plate,and then BMSCs treated by mitomycin were added according to different ratios (BMSCs/peripheral blood monouclear cells).At the end,the cells were cultured as follows:Method 1:DMEM+10% fetal calf serum+1 μmol/L RA +20 μg/L basic fibroblast growth factor+20 μg/L epidermal growth factor.Method 2:DMEM+2% dimethyl sulfoxide +100 μmol/L butylated hydroxyanisole.MAIN OUTCOME MEASURES:The growth rate of lymphocyte was measured by ~3H-Thymidine,and the effect of BMSCs on lymphocyte proliferation was observed.Additionally,the differentiation potential of BMSCs into neuronel cells was determined by immunofluorescenca and immunohistochemistrical staining.RESULTS:①The BMSCs inhibited lymphocyte proliferation in MLR system and the influence on proliferation of lymphocyte was direct related to ratio of BMSCs.②Under a light microscope,cytoplasm of BMScs were shrinkd,which presented typical perikaryon morphology at hour 2 after culture with method 1.The majority of BMSCs were formed neuronal-like cells without number changes at hours 3-5,which turned to be dipolar or multipolar neuronal shapes at day 3.There were 60%-70% neuronspecific enolase,45%-50% glial fibrillary acidic protein were positive expressed.However,the positive rate of nidogen was decreased 3.4%.Cells cultured with method 2 became smaller after 2 hours,formed dipolar or multipolar body cells,and most of cells were died after 48 hours.The 40%-50% neuronspecific enolase,35%-40% glial fibrillary acidic protein was found to be positive.The positive rate of nidogen was temporary increased to 63% at hour 2 after culture；however,it was decreased to 1.6% after 48 hours.CONCLUSION:BMSCs can differentiate into neuronal-like cells,as well as inhibit lymphocyte proliferation in MLR system,which possess down regulation effect on alloimmunity-reaction.