Upregulation of neuronal amyloid precursor protein (APP) and APP mRNA following magnesium sulphate (MgSO4) therapy in traumatic brain injury

The aim of this study was to assess and quantitate topographically the effe cts of posttraumatic intravenous magnesium sulphate (MgSO4) on neuronal per ikaryal APP antigen and messenger RNA (mRNA) expression in sheep brains 2 h after a controlled focal head impact. The percentage brain rea with APP im munoreactive neuronal perikarya was 71, 56, 27.5 and 5.5%, respectively, in MgSO4-treated head-injured animals, head-injured animals without any treat ment, MgSO4 treated nonimpacted animals, and nontreated nonimpacted control sheep. Although there was no statistically significant difference in APP i mmunoreactive neuronal perikarya in the MgSO4-treated Hf group (mean 71%) c ompared to the HI group without any treatment (mean 56%), northern analysis showed that there was a 2.3- +/- 0.2-fold increase in APP mRNA in the thal amus of treated impacted animals compared to untreated impacted animals (p < 0.005), However, MgSO4 treated nonimpacted control animals also showed a 1.6- +/-0.1-fold increase in APP mRNA compared to untreated nonimpacted con trols (p < 0.005), MgSO4 therapy results in upregulation of neuronal APP mR NA and APP expression that is quantitatively greater following a focal head impact.