Changes in cortical and cerebellar bcl-2 mRNA levels in the developing hydrocephalic rat (LEW-HYR) as measured by a real time quantified RT-PCR

Abstract

In order to evaluate the appearance of brain bcl-2 during development of the hydrocephalus, we measured levels of bcl-2 mRNA in the cortex and cerebellum of congenital hydrocephalic rats (LEW-HYR) at 1 and 2 weeks after birth using the quantified reverse transcriptase-polymerase chain reaction (RT-PCR) with TaqMan fluorogenic detection system. Normal and hydrocephalic siblings were killed 7 and 14 days after birth, and their cortices and cerebella were homogenized with the Isogen–chloroform mixtured solution. By means of the RT-PCR with genetic analyzer, the sequence of bcl-2 mRNA detected in the LEW-HYR was identified to be the same as that of the registered rat brain (L14680). During the development of normal siblings of LEW-HYR, the levels of bcl-2 mRNA detected in the cortex and cerebellum 7 days after birth were significantly higher than those seen on day 14 after birth. In the hydrocephalic rats, however, these levels were not significantly different during development. On days 7 and 14 after birth, the cortical levels of bcl-2 mRNA detected in the hydrocephalic rats were significantly higher than those in normal rats. In the cerebellum, these levels in the hydrocephalic rats were higher, but not significantly, than those of normal rats. These results indicate that the significant appearance of bcl-2 mRNA in the developing normal rat brain is related to sprouting and to the diminished number of neurons, whereas the significant increase of bcl-2 levels seen in the developing hydrocephalic rats is indicative of an excess activity of glutamate neurons in cerebral cortex and the protection of neurons from cell death induced by cerebral ventricular dilatation in the cortex after bcl-2 levels.