ABSTRACT
Objective To investigate the role of Stat1 in pathological process of nerve cells apoptosis induced by diffuse axonal injury (DAI) on rats. MethodsThe DAI model was established by using an injury model adapted from Marmarou et al. in 1994. All animals were divided into three groups, including control group, mock group and test group sacrificed on 6, 12, 24, 48, 72, 120 and 240 hours post injury (hpi). The paraffin-embedded sections of brain tissue were processed for HE staining and Bielschowsky’s silver method. Cell apoptosis was examined by flow cytometry and the expression of bax and bcl-2 were analyzed by RT-PCR. And Phospho-Ser727 Stat1 expression was examined by immunohistochemistry in different brain regions. ResultsThere was no brain contusion within HE staining, however, waving and enlargement of axons were observed within Bielschowsky’s silver method. The apoptotic rate of brain cells as well as PCR products ratio of bax to bcl-2 was highest at 24 hpi and decreased with time. An up-regulation of Phospho-Ser727 Stat1 at 6 hpi was discernible, and then reached the top at 24 hpi in cortex, cerebellum, brain stem and corpus callosum, and at 12 hpi in hippocampus. This increase was associated with the nerve cells apoptosis, r=0.921. In addition, the Phospho-Ser727 Stat1 positive cells were neurons and glial cells assessed from morphous. ConclusionsOur data indicate that Stat1 may contribute to the apoptosis of DAI on rats. In addition, the expression of Phospho-Ser727 Stat1 in glial cells suggested that glial cells may play an important role in the pathogenic mechanism of DAI.