Differential expression of small heat shock protein 27 in the rat hippocampus and septum after fimbria-fornix lesion

mRNA, Western analysis and immunohistochemistry were used to study the expr ession of the small heat shock protein (HSP) 27 in the rat septum and hippo campus following fimbria-fornix lesions, a model of neurodegeneration and r egeneration. (HSP) 27 mRNA level was increased 2.5-fold in the medial septu m 3 days after lesion and this increase persisted for 10 days. In the hippo campus, after an initial 15-fold increase at 3 days post-injury, HSP27 mRNA returned to basal levels 10 days after the lesion. Three and 10 days after lesion, HSP27 protein levels were increased in the septum (4.5 and 5-fold, respectively) and hippocampus (65 and 10-fold, respectively). The morpholo gy of the HSP27 positive cells was indistinguishable from that of GFAP-immu noreactive cells. In addition, in the septum of injured rats, occasional ne urons were heavily labelled with anti-HSP27 antibodies. Thus, up-regulation of HSP27, particularly in glial cells, may be a component of glial input i n the processes on degeneration/regeneration which occur in this model. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.