Email updates

Keep up to date with the latest news and content from JNI and BioMed Central.

Open Access Research

Increased circulating leukocyte numbers and altered macrophage phenotype correlate with the altered immune response to brain injury in metallothionein (MT) -I/II null mutant mice

Michael W Pankhurst12*, William Bennett1, Matthew TK Kirkcaldie3, Adrian K West1 and Roger S Chung1

Author Affiliations

1 Menzies Research Institute Tasmania, University of Tasmania, 17 Liverpool Street, Hobart, Tasmania, Australia

2 Department of Anatomy, University of Otago, 270 Great King St, Dunedin, New Zealand

3 School of Medicine, University of Tasmania, 17 Liverpool Street, Hobart, Tasmania, Australia

For all author emails, please log on.

Journal of Neuroinflammation 2011, 8:172  doi:10.1186/1742-2094-8-172

Published: 7 December 2011



Metallothionein-I and -II (MT-I/II) is produced by reactive astrocytes in the injured brain and has been shown to have neuroprotective effects. The neuroprotective effects of MT-I/II can be replicated in vitro which suggests that MT-I/II may act directly on injured neurons. However, MT-I/II is also known to modulate the immune system and inflammatory processes mediated by the immune system can exacerbate brain injury. The present study tests the hypothesis that MT-I/II may have an indirect neuroprotective action via modulation of the immune system.


Wild type and MT-I/II-/- mice were administered cryolesion brain injury and the progression of brain injury was compared by immunohistochemistry and quantitative reverse-transcriptase PCR. The levels of circulating leukocytes in the two strains were compared by flow cytometry and plasma cytokines were assayed by immunoassay.


Comparison of MT-I/II-/- mice with wild type controls following cryolesion brain injury revealed that the MT-I/II-/- mice only showed increased rates of neuron death after 7 days post-injury (DPI). This coincided with increases in numbers of T cells in the injury site, increased IL-2 levels in plasma and increased circulating leukocyte numbers in MT-I/II-/- mice which were only significant at 7 DPI relative to wild type mice. Examination of mRNA for the marker of alternatively activated macrophages, Ym1, revealed a decreased expression level in circulating monocytes and brain of MT-I/II-/- mice that was independent of brain injury.


These results contribute to the evidence that MT-I/II-/- mice have altered immune system function and provide a new hypothesis that this alteration is partly responsible for the differences observed in MT-I/II-/- mice after brain injury relative to wild type mice.

Metallothionein; cryolesion; brain injury; alternatively activated macrophages