The role of 8-OH-DPAT on the rat neuronal apoptosis after diffuse brain injury coupled with secondary brain injury.

The potential role of 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) on rat neuronal apoptosis after diffuse brain injury (DBI) coupled with secondary brain injury (SBI) was investigated. One hundred and twelve adult male Wister rats weighing 305-355 g were randomly divided into four groups and received an intraperitoneal injection of 8-OH-DPAT (0.5 mg/kg) or an equal volume of normal saline. Neurological severity score (NSS) was recorded and the injured extent was observed after hematoxylin-eosin (HE) staining. The neuronal cell apoptosis index and the expression of Bax and Bcl-2 were detected by TUNEL method and immunohistochemistry respectively. We found a higher NSS value for rats in the DBI + SBI groups compared with those in normal control and sham-operated control groups (P < 0.01). HE staining showed that 8-OH-DPAT treatment could alleviate the occurrence of injury in rats CA3 hippocampus and PFC. The neuronal apoptosis index decreased in the 8-OH-DPAT treatment group compared with the NS group (P< 0.05) and gradually increased at 6 h, reached the peak level at 72 h and still had a high performance at 168 h in not only CA3 hippocampus but also PFC. Expression of Bax and Bcl-2 increased after DBI + SBI, however, with 8-OH-DPAT treatment Bcl-2 expression increased while Bax expression decreased. 8-OH-DPAT had an inhibitory effect on the rat neuronal apoptosis in CA3 hippocampus and PFC after DBI coupled with SBI.