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. Author manuscript; available in PMC: 2018 Nov 1.
Published in final edited form as: Acta Biomater. 2017 Sep 13;63:50–63. doi: 10.1016/j.actbio.2017.09.011

Figure 4. ECM hydrogel retention and glial scarring.

Figure 4

A A histological comparison between controls, untreated and treated stroke animals reveals a major tissue loss in the ipsilateral hemisphere, as well as the presence of ECM hydrogel within the lesion cavity. B. A quantification of parenchymal volume in these 3 groups indicated a 33% tissue loss in animals with stroke, as well as a dramatic increase in ipsilateral ventricular volume. A treatment effect was evident on stroke lesion volume with a 19.8% decrease in cavity volume. C. ECM hydrogel was retained inside the lesion cavity in all treated animals as indicated by collagen I staining surrounded by host tissue. D. Along the anterior-posterior axis, ECM hydrogel was identifiable as a morphologically distinct entity aided by collagen I staining. E. A comparison between injection volume of ECM gel precursor and volume of hydrogel at 3 months revealed a decrease of 32%, but due to individual variability this did not reach statistical significance. F. To evaluate the impact of ECM hydrogel on glial scarring at the tissue interface, whole brain slice images covering the lesion cavity along the anterior-posterior axis were acquired for all 3 groups to measure the level of astrocytic (GFAP) reactivity inside striatal and cortical tissue. G. A marked increase in GFAP staining was evident at the border of the lesion cavity that gradually decreased further inside the tissue. GFAP reactivity in the stroke-damaged striatum was higher than in the cortex. However, there was no significant difference between untreated and treated animals. H. Peri-infarct astrocytosis (i.e. the area occupied by reactive astrocytes) in the ipsilateral and contralateral parenchyma was measured by an 8-bit conversion of whole slice images to apply a threshold that created a binary map. I. This binary image afforded quantification of area occupied and provided a comparison of the 3 experimental groups to indicate that there was no significant difference between untreated and treated animals, although both had significantly more astrocytosis than normal controls. Scale bar 2 mm.