ISSN : 2146-3123
E-ISSN : 2146-3131

Astrogliosis has Different Dynamics after Cell Transplantation and Mechanical Impact in the Rodent Model of Parkinson's Disease
Nikola Tomov1, Lachezar Surchev2, Clemens Wiedenmann3, Máté Daniel Döbrössy3, Guido Nikkhah4
1Department of Anatomy, Faculty of Medicine, Trakia University, Stara Zagora, Bulgaria
2Department of Anatomy, Histology and Embryology, Medical University of Sofia, Sofia, Bulgaria
3Neurocenter, University Medical Center Freiburg, Freiburg, Germany
4Department of Stereotactic Neurosurgery, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen Germany
DOI : 10.4274/balkanmedj.2016.1911

Background: Transplantation of fetal mesencephalic tissue is a well-established concept for functional reinnervation of the dopamine-depleted rat striatum. However, no extensive description of the glial reaction of the host brain following this procedure has been carried out.
Aims: The present study aims at a quantitative and qualitative analysis of the astrogliosis surrounding intrastriatal grafts and comparing it to the reaction caused by a mechanical injury with the transplantation instrument only.
Study Design: Animal experimentation.
Methods: The standard 6-hydroxydopamine induced unilateral model of Parkinson"s disease was used. The experimental animals received a transplantation of single-cell suspension of E14 ventral mesencephalic tissue. Control animals (sham-transplanted) were subjected to an impact by the transplantation cannula, without injection of cell suspension. Histological analysis was carried out 7 and 28 days following the procedure by means of immunohistochemistry for tyrosine hydroxylase (TH) and glial fibrilary acidic protein (GFAP). For evaluation of astrogliosis, cell density and immunopositive area fraction were measured in distinct zones inside and surrounding the grafts, or surrounding the cannula tract respectively.
Results: Statistical analysis revealed that astrogliosis in the grafted striatum increases from day 7 to day 28 as shown by the change of both parameters. Cell density (cells/mm2) changed from 816.7±370.6 to 1403±272.1, p<0.0001 аnd from 523±245.9 to 1164±304.8, p<0.0001 for the two zones in the graft core and from 1151±218.6 to 1485±210.6, p<0.05 for the zone in the striatum immediately adjacent to the graft. The GFAP expressing area fraction increased from 0.3109±0.1843 to 0.7949±0.1910, p<0.0001 and from 0.1449±0.1240 to 0.702±0.2558, p<0.0001 for the same zones in the graft core, and from 0.5277±0.1502 to 0.6969±0.1223, p<0.0001 for the same adjacent to the graft zone. However, astrogliosis caused by mechanical impact only does not show such dynamics. This finding implies an extended influence of grafted cells on the host"s glia, possibly through cross-talk between astrocytes and transplanted neurons.
Conclusion: This bidirectional relationship is affected by multiple factors, well beyond the mechanical trauma. Elucidation of those factors might contribute towards achieving a better functional effect of intracerebral transplantation.

Keywords : Astrocytes, gliosis, transplantation
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