Neuronal damage using Fluoro-Jade B histofluorescence and gliosis in the striatum after various durations of transient cerebral ischemia in gerbils

Introduction

Ischemic damage occurs well in vulnerable regions of the brain, including the hippocampus and striatum. In the present study, we examined neuronal damage/death and glial changes in the striatum 4 days after 5, 10, 15 and 20 minutes of transient cerebral ischemia using the gerbil. Spontaneous motor activity was shown to be increased with the duration time of ischemia-reperfusion (I-R).

Methods

To examine neuronal damage, we used Fluoro-Jade B (F-JB, a marker for neuronal degeneration) histofluorescence staining. F-JB-positive cells were detected only in the 20-minute ischemia group, not in the other groups. In addition, we examined gliosis of astrocytes and microglia using antiglial fibrillary acidic protein (GFAP) and anti-ionized calcium-binding adapter molecule 1 (Iba-1), respectively.

Results

In the 5-minute ischemia group, GFAP-immunoreactive astrocytes were distinctively increased in number, and the immunoreactivity was stronger than that in the sham group. In the 10-minute, 15-minute and 20-minute ischemia groups, GFAP immunoreactivity was more increased with the duration of I-R. On the other hand, the immunoreactivity and number of Iba-1-immunoreactive microglia were distinctively increased in the 5-minute and 10-minute ischemia groups. In the 15-minute ischemia group, microglia were largest in size, and the immunoreactivity was highest; however, in the 20-minute ischemia group, the immunoreactivity was low compared to the 15-minute ischemia group. The results of western blotting for GFAP and Iba-1 were similar to the immunohistochemical data.

Conclusion

These findings indicate that neuronal death was detected only in the 20-minute ischemia group 4 days after I-R; in addition, the change pattern of astrocytes and microglia were apparently different according to the duration time of I-R.