Semi-quantitative analyses of hippocampal heat shock protein-70 expression based on the duration of ischemia and the volume of cerebral infarction in mice.

Abstract

OBJECTIVE:

We investigated the expression of hippocampal heat shock protein 70 (HSP-70) infarction volume after different durations of experimental ischemic stroke in mice.

METHODS:

Focal cerebral ischemia was induced in mice by occluding the middle cerebral artery with the modified intraluminal filament technique. Twenty-four hours after ischemia induction, both hippocampi were extracted for HSP-70 protein analyses. Slices from each hemisphere were stained with 2,3,5-triphenyltetrazolium chloride (2%), and infarction volumes were calculated. HSP-70 levels were evaluated using western blot and enzyme-linked immunosorbent assay (ELISA). HSP-70 subtype (hsp70.1, hspa1a, hspa1b) mRNA levels in the hippocampus were measured using reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS:

Cerebral infarctions were found ipsilateral to the occlusion in 10 mice exposed to transient ischemia (5 each in the 30-min and 60-min occlusion groups), whereas no focal infarctions were noted in any of the sham mice. The average infarct volumes of the 2 ischemic groups were 22.28±7.31 mm(3) [30-min group±standard deviation (SD)] and 38.06±9.53 mm(3) (60-min group±SD). Western blot analyses and ELISA showed that HSP-70 in hippocampal tissues increased in the infarction groups than in the sham group. However, differences in HSP-70 levels between the 2 infarction groups were statistically insignificant. Moreover, RT-PCR results demonstrated no relationship between the mRNA expression of HSP-70 subtypes and occlusion time or infarction volume.

CONCLUSION:

Our results indicated no significant difference in HSP-70 expression between the 30- and 60-min occlusion groups despite the statistical difference in infarction volumes. Furthermore, HSP-70 subtype mRNA expression was independent of both occlusion duration and cerebral infarction volume.

• Authors: Jong-Il Choi, Sang-Dae Kim, Se-Hoon Kim, Dong-Jun Lim, Sung-Kon Ha
• Journal: Journal of Korean Neurosurgical Society (J Korean Neurosurg Soc) Vol. 55 Issue 6 Pg. 307-12 (Jun 2014) ISSN: 2005-3711 [Print] Korea (South)
• PMID: 25237425 (Publication Type: Journal Article)