Research Article

Repetitive Hyperbaric Oxygenation Attenuates Reactive Astrogliosis and Suppresses Expression of Inflammatory Mediators in the Rat Model of Brain Injury

Figure 3

Repetitive HBOT reduces gene and tissue expression of ICAM-1 after CSI. (a) Repetitive HBOT attenuated injury-induced upregulation of ICAM-1 mRNA expression in the injured cortex. Bars represent mean ± SEM of ICAM-1 mRNA (relative to GAPDH). Samples are from 4 animals per each group. Dot line represents mean of ICAM-1 mRNA level ± SEM (gray area) measured in control animals. Letters indicate significance levels () between lesioned (L) and intact control groups, L versus sham control (S) group, and L compared to lesioned group subjected to the HBO protocol (LHBO). The groups not sharing a common letter are statistically different. Level of significance was analyzed using Student’s -test. (b) In the control cortex ICAM-1 localization is present on the blood vessels (asterisk). ((c) and (d)) An increased ICAM-1 immunoreactivity is seen around the lesion site after the CSI. Heavy immunostaining of blood vessels is demonstrated both in ipsilateral (asterisk (d) and (e) inset) and contralateral cortex (asterisk (e) and (e) inset). The arrow denotes dark neuron-like cells in injured (d) and contralateral cortex (e). ICAM-1-positive neutrophils, microglia ((c), (c) inset), and astrocyte-like cells ((d), arrow head) were confined to the lesion area. (f) and (g) Repetitive HBOT reduced ICAM-1 immunoreactivity, while blood vessels were faintly stained ((g) asterisk). Rectangles indicate where the high magnification images are taken from. Scale bar = 50 μm.