Objective To investigate the effects of Calpain
inhibitor Ⅰ on the
secondary axotomy of nondisruptive axonal injury (NDAI)
after diffused brain injury (DBI) in rats and discuss the way to prevent NDAI from
secondary axotomy. Methods A total of 16 male Sprague-Dawley rats were randomly and equally divided into control group and Calpain inhibitor Ⅰ group. The axonal
swellings and axonal balls were detected by NF68 immunochemistry after DBI caused by fluid percussion. The changes of maximal density of axonal swellings and axonal balls in calosum, diencephalon-mesencephalon, pons-oblongata and cerebellum were compared between both groups 24 and 72 hours respectively after injury. Results NF68 immunoche mistry showed swelled axons and axonal balls after injury. In Calpain inhibitor I group, the maximal density of axonal swellings and axonal balls in the pons-oblongata and the cerebellum was obviously decreased 24 hours after injury (P<0.01). At the 72nd hour after injury, the maximal density of axonal swellings and axonal balls significantly decreased only in the cerebellum (P<0.05), while there was no significant difference between Calpain inhibitor I group and control group in the calosum, the diencephalon-mesencephalon and the pons-oblongata(P>0.05). Conclusion Calpain inhibitor I can decrease reactive changes of NDAI after injury and prevent mild NDAI from secondary axotomy.