Neurotherapeutic activity of the recombinant heat shock protein Hsp70 in a model of focal cerebral ischemia in rats

Abstract

Recombinant 70 kDa heat shock protein (Hsp70) is an antiapoptotic protein that has a cell protective activity in stress stimuli and thus could be a useful therapeutic agent in the management of patients with acute ischemic stroke. The neuroprotective and neurotherapeutic activity of recombinant Hsp70 was explored in a model of experimental stroke in rats. Ischemia was produced by the occlusion of the middle cerebral artery for 45 minutes. To assess its neuroprotective capacity, Hsp70, at various concentrations, was intravenously injected 20 minutes prior to ischemia. Forty-eight hours after ischemia, rats were sacrificed and brain tissue sections were stained with 2% triphenyl tetrazolium chloride. Preliminary treatment with Hsp70 significantly reduced the ischemic zone (optimal response at 2.5 mg/kg). To assess Hsp70’s neurotherapeutic activity, we intravenously administered Hsp70 via the tail vein 2 hours after reperfusion (2 hours and 45 minutes after ischemia). Rats were then kept alive for 72 hours. The ischemic region was analyzed using a high-field 11 T MRI scanner. Administration of the Hsp70 decreased the infarction zone in a dose-dependent manner with an optimal (threefold) therapeutic response at 5 mg/kg. Long-term treatment of the ischemic rats with Hsp70 formulated in alginate granules with retarded release of protein further reduced the infarct volume in the brain as well as apoptotic area (annexin V staining). Due to its high neurotherapeutic potential, prolonged delivery of Hsp70 could be useful in the management of acute ischemic stroke.

Keywords:

• focal ischemia
• stroke
• neuroprotection
• neurotherapy
• alginate granules

Supplementary material

Figure S1 The basic parameters of cerebral blood flow during all phases of rat stroke modeling.

Abbreviations: CCA, common carotid artery; MCA, middle cerebral artery.

Acknowledgments

We are grateful to Olga G Genbach, Nelly V Koroleva, Dmitriy N Suslov, Oleg V Galibin, Tatiana V Zakoldaeva, Irina V Kononova, and Yulia E Shevchuk for their assistance with animal experiments. We thank Olga M Suvorova and Larisa P Chokova for manufacturing the alginate granules, and Vladimir D Pautov for performing the spectrofluorometer studies. This work was supported by grants from the Russian Foundation for Basic Research (14-08-00614), a grant from the Program of Molecular and Cellular Biology (RAS), and a government grant (20.11.2012), No 14.N08.11.0001.

Disclosure

The authors report no conflicts of interest in this work.