Hyperbaric oxygen for suppressing glial scar formation and inflammation after a stab wound to the cerebral cortex / 中华物理医学与康复杂志

ABSTRACT

Objective To observe any influence of hyperbaric oxygen (HBO) treatment on the formation of glial scars,and to explore how HBO suppresses the inflammatory reaction to injury.Methods A total of 96 healthy,adult,male,Sprague-Dawley rats were used to model cerebral puncture injury.They were then randomized into a control group and a treatment group,with 48 rats in each group.The treatment group received HBO treatment,while the control group received no special treatment.At 1,3,7,14 and 28 days after the puncture injury,the rats' right brain tissues were harvested and immunohistochemical staining was employed to compare the changes in number of astrocytes and microglial cells around the injury in the two groups.The level of tumor necrosis factor α (TNF-α) and interleukin 1 β (IL-1β) in the cerebral tissue was examined using ELISA.Results Among the control group the average wound areas after 7,14 and 28 days were (2.73 ± 0.05)μm2,(3.42 ± 0.18)μm2 and (2.41 ± 0.09) μm2,a significant reduction after 28 days compared with 7 and 14 days.The corresponding average wound areas of rats in the treatment group were (2.78±0.12)μm2,(2.59 ±0.08)μm2 and (1.20 ±0.06)μm2.There the average wound area had decreased significantly after 14 days,and the further reduction after 28 days was also significant.The numbers of GFAP-positive astrocytes at 14 and 28 days had increased significantly compared with after 7 days in both the control group and the treatment group.The average number of GFAP-positive astrocytes in the control group at 28 days had decreased significantly compared with after 14 days.Compared with the control group at the same time points,the number of GFAP-positivc astrocytes in the treatment group was significantly less.After modeling,the number of ionized calcium-binding adapter molecule Ⅰ (Ibal)-positive microglial cells increased significantly,but there was a significant decrease in both the control and treatment groups by 7 days.The average number of Ibal-positive microglial cells in the treatment group was significantly less than in the control group at all of the time points.Compared with the first day after modeling,the TNF-α concentration of the controls at 3 and 7 days was significantly higher,but by the 7th day it was significantly lower than it had been after 3 days.The average IL-1β concentration in the control group and TNF-α concentration in the treatment group had increased by day 3,but then decreased by day 7.The IL-1β concentration of the treatment group declined gradually.The average TNF-α and IL-1 β concentrations of the treatment group were significantly lower than those of the control group at all of the time points.Conclusion HBO treatment has a relatively good curative effect on cerebral puncture injury.It can accelerate wound healing and reduce the formation of glial scars.Its mechanism could be related to the deactivation of astrocytes and microglia cells and reducing the levels of cell factors that promote inflammation.