Stability of rat models of fluid percussion-induced traumatic brain injury: comparison of three different impact forces

Fluid percussion-induced traumatic brain injury models have been widely used in experimental research for years. In an experiment, the stability of impaction is inevitably affected by factors such as the appearance of liquid spikes. Management of impact pressure is a crucial factor that determines the stability of these models, and direction of impact control is another basic element. To improve experimental stability, we calculated a pressure curve by generating repeated impacts using a fluid percussion device at different pendulum angles. A stereotactic frame was used to control the direction of impact. We produced stable and reproducible models, including mild, moderate, and severe traumatic brain injury, using the MODEL01-B device at pendulum angles of 6°, 11° and 13°, with corresponding impact force values of 1.0 ± 0.11 atm（101.32 ± 11.16 k Pa）, 2.6 ± 0.16 atm（263.44 ± 16.21 k Pa）, and 3.6 ± 0.16 atm（364.77 ± 16.21 k Pa）, respectively. Behavioral tests, hematoxylin-eosin staining, and magnetic resonance imaging revealed that models for different degrees of injury were consistent with the clinical properties of mild, moderate, and severe craniocerebral injuries. Using this method, we established fluid percussion models for different degrees of injury and stabilized pathological features based on precise power and direction control.

Role of Regulatory T cell in Clinical Outcome of Traumatic Brain Injury

Background： Traumatic brain injury （TBI） is a life-threatening disease worldwide. Regulatory T cells （Treg ceils） were involved in the immunological system in central nervous system. It is defined as a subpopulation of CD4＋ cells that express CD25 and transcription lactor forkhead box P3. The level of circulating Treg cells increases in a variety of pathologic conditions. The purpose of this study was to uncover the role of circulating Treg cells in TBI. Methods： A clinical study was conducted in two neurosurgical intensive care units of Tianjin Medical University General Hospital and Second Hospital of Tianjin Medical University （Tianjin, China）. Forty patients and 30 healthy controls were recruited t＇rom August 2013 to November 2013. Circulating Treg cells was detected on the follow-up period of 1,4, 7, 14, and 21 days alter TBI. Blood sample （ 1 ml） was withdrawn in the morning and processed within 2 h. Results： There was no significant difference in the level of circulating Treg cells between TBI patients and normal controls during follow-up. TBI patients exhibited higher circulating Treg level than normal controls on the 1st day after TBI. Treg level was decreased on the 4th day, climbed tip on the 7th day and peaked on 14th day after TBI. Treg cells declined to the normal level on 21th day alter TBI. The level of circulating Treg cells was significantly higher in survival TBI patients when compared to nonsurvival TBI patients. TBI patients with improved conditions exhibited significantly higher circulating Treg level when compared to those with deteriorated conditions. The circulating Treg level was correlated with neurologic recovery after TBI. A better neural recovery and lower hospital mortality were found in TBI patients with circulating Treg cells more than 4.91% in total CD4＋ inononuclear cells as compared to those with circulating Treg cells less than 4.91% in total CD4 mononuclear cells in the first 14 days. Conclusions： The level of circulating Treg cells is positively correlated with clinical outcome of TBI. The level of Treg cells predicts the progress for TBI patients and may be a target in TBI treatment.