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.