Representative H&E images of non-perfused (A) and perfused (B) rat brains 30 days after cOFM probe implantation.

<p>Representative H&E images of non-perfused (A) and perfused (B) rat brains 30 days after cOFM probe implantation.</p

Quantification of GFAP positive cells 15 days after cOFM implantation at different distances from the probe tip and in the corresponding area on the contralateral hemisphere (control).

<p>Quantification of GFAP positive cells 15 days after cOFM implantation at different distances from the probe tip and in the corresponding area on the contralateral hemisphere (control).</p

Quantification of GFAP+ cells 15 days after cOFM probe implantation.

<p>p values were calculated by comparing GFAP cell counts in each area with the contralateral control area.</p

Measurement of TNF-α concentration in the frontal cortex and serum after LPS injection (i.p.).

<p><b>A</b>: Control animals (n = 7) received normal sterile saline (0.5 ml; i.p.) after the collection of baseline cOFM samples, whereas the LPS-treated group (n = 7) were injected with LPS (i.p.; 5 mg/kg dissolved in 0.5 ml normal sterile saline) after baseline cOFM sample collection. TNF-alpha concentration in the control animals and in the baseline cOFM sample as well as 1 h after LPS injection was very close to the lower limit of quantification (0.004 ng/ml). <b>B</b>: Serum TNF-alpha concentration in control animals and in the baseline sample of the LPS-treated group was below the lower limit of quantification. The serum level of TNF-alpha was found to be significantly elevated from 2 to 6 h after LPS injection. Results are shown as mean ± SEM. (* p<0.05; ** p<0.01).</p

Microscopy of Iba-1 (A) and GFAP immunoreactivity (B) 3 days after cOFM probe implantation (200×).

<p>Microscopy of Iba-1 (A) and GFAP immunoreactivity (B) 3 days after cOFM probe implantation (200×).</p

Schematic representation of quantification pattern.

<p>Each square has a size of 4,900 µm²; 200× magnification. Checked squares indicate the areas selected for cell count.</p

Representative scanning electron microscope image of non-implanted cOFM probe (A) and a cOFM probe implanted for 15 days (B).

<p>Representative scanning electron microscope image of non-implanted cOFM probe (A) and a cOFM probe implanted for 15 days (B).</p

Representative images of the microdialysis membrane (CMA 12; cut-off 20,000 Da) implanted in the frontal cortex of Sprague Dawley rats.

<p>(A) Classic morphology of reactive astrocytes (GFAP) around the microdialysis probe 15 days after probe implantation. (B) Increased Iba-1+ microglia in close vicinity of the microdialysis probe 15 days after implantation. The arrows point towards the outer surface of the microdialysis membrane.</p

Microscopy of the cOFM probe implantation site in the frontal cortex after 15 days.

<p>Representative images of non-perfused (A–F) and perfused (G–L) rat brains. Adjacent brain slides were stained with H&E (A, D, G, J), Iba-1 for microglia (B, E, H, K) and GFAP for astrocytes (C, F, I, L). Rectangles with broken lines in A–C and G–I (50×) are shown at higher magnification (200×) in D–F and J–L, respectively. At this stage only a minimal residual edema is detectable with H&E staining in both non-perfused and perfused animals. Only a minor microglial (E, K) and astrocytic (F,L) reaction is visible directly adjacent to the cOFM probe implantation site.</p

Quantification of Iba-1 positive cells 15 days after cOFM implantation at different distances from the probe tip and in the corresponding area on the contralateral hemisphere (control).

<p>Quantification of Iba-1 positive cells 15 days after cOFM implantation at different distances from the probe tip and in the corresponding area on the contralateral hemisphere (control).</p