Elsevier

Experimental Neurology

Volume 233, Issue 2, February 2012, Pages 776-782
Experimental Neurology

Effects of rehabilitative training and anti-inflammatory treatment on functional recovery and cellular reorganization following stroke

https://doi.org/10.1016/j.expneurol.2011.11.037Get rights and content

Abstract

Post-ischemic inflammation plays a critical role in cellular reorganization and functional recovery after stroke. We therefore address the hypothesis whether anti-inflammatory treatment with either indometacin or minocycline combined with rehabilitative training improve functional recovery and influence perilesional cellular response following focal cortical infarcts. Using the photothrombosis model in adult rats, focal cortical infarcts were induced in the fore- and hindlimb sensorimotor cortex. Inflammatory processes were blocked by intraperitoneal application of indometacin or minocycline twice daily during the first 2 weeks of the experiment. Immediately after the infarct, the animals received a daily session of skilled reaching training of the impaired forelimb. In addition, Bromodeoxyuridine (BrdU) was administrated for 5 sequential days post infarct. Proliferation and differentiation of astrocytes, microglia, immature and mature neurons in the perilesional zone were immunocytochemically quantified at days 14 and 42. Functional recovery was assessed in a sensorimotor walking task preoperatively and 4, 14 and 28 days post surgery. Combined rehabilitative training and indometacin or minocycline strongly improved sensorimotor performance and significantly reduced the number of proliferating microglia compared to reaching training alone. Furthermore, the combination increased the survival of proliferating astrocytes and, moreover, minocycline increased the doublecortin-positive cells in the perilesional zone. Anti-inflammatory drug application combined with rehabilitative training demonstrates improved functional recovery and significantly modifies proliferation and survival of distinct glial and neuronal subpopulations in the direct vicinity of cortical infarcts compared to reaching training alone.

Highlights

► Combined anti-inflammatory treatment and rehabilitation improve sensorimotor outcome post stroke. ► This treatment also suppresses proliferating microglia in the peri-infarct zone. ► Minocycline increases DCX-positive cells and generates some new neurons. ► Anti-inflammatory medication might favour efficacy of rehabilitation after stroke.

Introduction

Sensorimotor impairments are the most common disabilities caused by stroke (Thom et al., 2006). Recent experimental studies in rodents have shown that physical activity, exposure to an enriched environment, and daily reaching training of the impaired forelimb improves functional recovery after focal ischemic infarcts, although, these processes are often insufficient to restore normal levels of function (Dobkin, 2004, Keiner et al., 2008). On the other hand, basic and clinical research provides evidence that inflammatory mechanisms play a central role both in the pathogenesis and during functional recovery following stroke (Kriz and Lalancette-Hebert, 2009, Liu et al., 2007). We recently demonstrated (Keiner et al., 2008) that rehabilitative training of the impaired forelimb alone alters the cellular response in the perilesional zone with a prominent reduction of proliferating microglia. These results encouraged us to investigate whether enhanced functional recovery following infarct can be further promoted via a pharmacological reduction of microglia. Hence, we combined skilled reaching training of the impaired forelimb as described previously (Keiner et al., 2008) with additional treatment using indometacin or minocycline. Previous studies (Chu et al., 2010, Hoehn et al., 2005) have demonstrated that both drugs inhibit microglial activity after stroke. Using this approach, we provide evidence that rehabilitative training in combination with anti-inflammatory treatment enhanced functional recovery and modified the complex postlesional cellular reorganization in the direct vicinity of the infarct.

Section snippets

Photothrombotic infarction

The study was conducted in accordance with the animal care guidelines issued by the National Institute of Health and by the Institutional Animal Care and Use Committee. Photothrombotic infarcts were induced in a total of 50 male Wistar rats (3 months old, 250–300 g) in the forelimb and hindlimb sensorimotor cortex. The animals were anesthetized with 2.0–3.5% isofluran in a mixture of oxygen/nitrous oxide (30%/70%), placed in a stereotactic frame and illuminated with a cold light source (KL 1500,

Morphology of photothrombotic infarcts

All animals had typical photothrombotic infarcts involving all layers of the sensorimotor fore- and hindlimb cortex. Only animals that had received indometacin showed a significant decline in lesion volume at days 14 and 42 compared to vehicle (Fig. 1B).

Functional recovery

At the beginning of daily reaching training, all animals demonstrated functional impairments of the contralateral forelimb. Reaching success significantly increased between 82% and 98%, 1 week after drug application. During the second week,

Discussion

Rehabilitative training in combination with anti-inflammatory treatment following focal cortical infarcts leads to a better functional recovery of the impaired forelimb associated with significant changes of cellular response in the perilesional zone. In the acute phase of inflammation, skilled reaching training and indometacin or minocycline application strongly diminished proliferating microglia, while minocycline additionally increased the number of proliferating DCX-positive cells.

Conclusions

We demonstrate herein that treatment with indometacin or minocycline combined with rehabilitative training of the impaired function substantially modulates perilesional cellular plasticity following focal cortical infarcts and contributes to a better functional recovery. Our data suggest that anti-inflammatory co-medication supports the efficacy of rehabilitation following stroke. Hence, it seems worthwhile to establish whether this concept also functions in the clinical context using

Funding

Scholarship program of the Ernst-Abbe-Foundation Jena (IZKF scholarship program to S.L. and N.S., junior research program J12 to S.K.) and German Ministry of Education and Research (BMBF program ‘Cell-based, regenerative therapies’, 01GN0977 to C.R.).

The following are the supplementary materials related to this article.

. Primary antibodies and secondary antibodies used for immunohistochemistry.

Acknowledgments

We are grateful to Mrs N. Kroegel for editing the manuscript.

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