Bridging the Gap of Standardized Animals Models for Blast Neurotrauma: Methodology for Appropriate Experimental Testing

Characterization of Combined Blast- and Fragment-Induced Pelvic Injuries and Hemostatic Resuscitation in Rabbits

INTRODUCTION

To establish a blast- and fragment-induced pelvic injury animal model in rabbits, observe its injury characteristics, and explore the effects of hemostatic resuscitation combined with damage control surgery (DCS) with respect to this injury model.

METHODS

Forty-eight rabbits were randomly allocated to four groups: group A rabbits were subjected to pelvic injury, group B rabbits to pelvic injury + DCS, group C rabbits to pelvic injury + DCS + resuscitation with Hextend, and group D rabbits to pelvic injury + DCS + Hextend + hemostatic resuscitation with tranexamic acid, fibrinogen concentrate, and prothrombin complex concentrate. Simulated blast and fragment-induced pelvic injury was produced by a custom-made machine. We implemented CT scanning and necropsy to assess the injury state and calculated the coefficient of variation (CV) of the cumulative abbreviated injury scale (AIS) to assess the reproducibility of the animal model. Immediately after instrumentation (0 h), and 1 h, 2 h, 4 h, and 8 h after injury, blood samples were taken for laboratory tests.

RESULTS

We found that severe pelvic injury was produced with an AIS CV value of 10.32%, and the rabbits demonstrated severe physiologic impairment and coagulo-fibrinolytic derangements with high mortality. In rabbits of group D, however, physiologic and coagulo-fibrinolytic parameters were significantly enhanced with improved organ function and lowered mortality when compared with the other three groups.

CONCLUSIONS

We herein established in rabbits a blast- and fragment-induced pelvic injury animal model that exhibited high reproducibility, and we demonstrated that hemostatic resuscitation plus DCS was effective in improving the outcome.

Establishment of a combat damage control surgery training platform for explosive combined thoraco-abdominal injuries

PURPOSE

It is challenging to prepare military surgeons with the skills of combat damage control surgery (CDCS). The current study aimed to establish a damage control surgery (DCS) training platform for explosive combined thoraco-abdominal injuries.

METHODS

The training platform established in this study consisted of 3 main components: (1) A 50 m × 50 m square yard was constructed as the explosion site. Safety was assessed through cameras. (2) Sixteen pigs were injured by an explosion of trinitrotoluene attached with steel balls and were randomly divided into the DCS group (accepted DCS) and the control group (have not accepted DCS). The mortality rate was observed. (3) The literature was reviewed to identify the key factors for assessing CDCS, and testing standards for CDCS were then established. Expert questionnaires were employed to evaluate the scientificity and feasibility of the testing standards. Then, a 5-day training course with incorporated tests was used to test the efficacy of the established platform. In total, 30 teams attended the first training course. The scores that the trainees received before and after the training were compared. SPSS 11.0 was employed to analyze the results.

RESULTS

The high-speed video playback confirmed the safety of the explosion site as no explosion fragments projected beyond the wall. No pig died within 24 h when DCS was performed, while 7 pigs died in the control group. After a literature review, assessment criteria for CDCS were established that had a total score of 100 points and had 4 major parts: leadership and team cooperation, resuscitation, surgical procedure, and final outcome. Expert questionnaire results showed that the scientific score was 8.6 ± 1.25, and the feasibility score was 8.74 ± 1.19. When compared with the basic level, the trainees' score improved significantly after training.

CONCLUSION

The platform established in this study was useful for CDCS training.

Sex as a Biological Variable in Preclinical Modeling of Blast-Related Traumatic Brain Injury

Approaches to furthering our understanding of the bioeffects, behavioral changes, and treatment options following exposure to blast are a worldwide priority. Of particular need is a more concerted effort to employ animal models to determine possible sex differences, which have been reported in the clinical literature. In this review, clinical and preclinical reports concerning blast injury effects are summarized in relation to sex as a biological variable (SABV). The review outlines approaches that explore the pertinent role of sex chromosomes and gonadal steroids for delineating sex as a biological independent variable. Next, underlying biological factors that need exploration for blast effects in light of SABV are outlined, including pituitary, autonomic, vascular, and inflammation factors that all have evidence as having important SABV relevance. A major second consideration for the study of SABV and preclinical blast effects is the notable lack of consistent model design—a wide range of devices have been employed with questionable relevance to real-life scenarios—as well as poor standardization for reporting of blast parameters. Hence, the review also provides current views regarding optimal design of shock tubes for approaching the problem of primary blast effects and sex differences and outlines a plan for the regularization of reporting. Standardization and clear description of blast parameters will provide greater comparability across models, as well as unify consensus for important sex difference bioeffects.

Current ex Vivo and in Vitro Approaches to Uncovering Mechanisms of Neurological Dysfunction after Traumatic Brain Injury

Traumatic brain injury often leads to progressive alterations at the molecular to circuit levels resulting in epilepsy and memory impairments. Ex vivo and in vitro models have provided a powerful platform for investigating the multimodal alteration after trauma. Recent ex vivo analyses using voltage sensitive dye imaging, optogenetics, and glutamate uncaging have revealed circuit abnormalities following in vivo brain injury. In vitro injury models have enabled examination of early and progressive changes in activity while development of three-dimensional organoids derived from human induced pluripotent stem cells have opened novel avenues for injury research. Here, we highlight recent advances in ex vivo and in vitro systems, focusing on their potential for advancing mechanistic understandings, possible limitations, and implications for therapeutics.