Determination of plasma lysosomal enzyme activity and its relationship to severity of injury following blunt vehicular trauma in dogs

Objective: To determine plasma β-D-glucuronidase (βG) activity in the first 4 hours following injury in dogs struck by a motor vehicle, and to evaluate whether the degree of enzyme activity is correlated with the severity of injury. Design: A prospective clinical study. Setting: Veterinary Medical Teaching Hospital. Animals: Thirteen client-owned dogs that were presented to the Veterinary Hospital of the University of Pennsylvania between June and August 1999 for blunt vehicular trauma. Ten healthy student and staff-owned dogs served as controls. Interventions: None. Measurements: Plasma was analyzed for βG enzyme activity at the time of presentation (n = 13), and 1 and 4 hours (n = 7) following presentation to the Emergency Service for blunt vehicular trauma. The results were compared with enzyme activity from healthy controls evaluated serially over 4 hours. Fluorometric analysis using 96-well microtiter plates was used to perform the enzyme assays. The relationships between presentation (n = 13) and 4 hours (n = 7) of enzyme activity and 3 indices of metabolic and physical disturbance (serum pH, serum lactate and Animal Trauma Triage (ATT) score) at the time of presentation were also investigated. Main results: Of the 13 dogs, 7 fulfilled the inclusion criteria for comparison of enzyme activity of the trauma over time. A statistically significant difference in βG activity was found in the trauma group (mean 75.6 ± 10.4 U) at 4 hours following presentation compared with controls (mean 48.0 ± 6.4 U). This difference was suggested by 1 hour following presentation (trauma group, mean 70.4 ± 10.9 U; control group, mean 49.8 ± 5.5 U), although it did not reach statistical significance. Thirteen dogs fulfilled the inclusion criteria for comparison of only presentation enzyme activity with trauma severity score, serum lactate, and serum pH. No statistically significant relationship was found between the βö-glucuronidase activity and the presenting ATT score, serum lactate concentration, or serum pH at either presentation or 4 hours, although the power of these analyses was low. Conclusions: These results demonstrate that the activity of βG, a lysosomal enzyme, increases significantly in the systemic circulation in dogs 4 hours following blunt trauma. Additional research to include more severely injured dogs, a larger number of dogs, and to follow the course of injury for a longer period of time would be beneficial to further characterize βG activity following blunt trauma.