Ocular trauma - induced changes in aqueous and plasma biomarker expression levels

The effect of varied blast overpressure on the visual system pathology was studied in 22 male Dutch Belted rabbits weighing 1.5 – 2.5 kg. Blast overpressure (BOP) of 8, 12, and 17 psi (55, 83, and 117 kPa, respectively) was simulated using a compartmentalized, pressure driven shock tube, aiming to induce sub-lethal ocular trauma. Trauma-related protein biomarkers were found using Milliplex Rat Cytokine/Chemokine (RECYMAG65K27PMX) and Human Neurological Disorders Panels (HND1MAG-39K) in aqueous humor (100 ?l) and blood plasma (2 ml) samples, obtained from anesthetized animals following primary blast ocular trauma. Parameters used were baseline, 24, and 48 hours, along with baseline, 3, 24, and 48 hours, for aqueous humor and blood plasma, respectively. Biomarkers concentrations were normalized for all animals subjected to BOP for each time point (n=22) (Fig. 4). Fold changes were plotted as a function of blast impulse, portraying significant linear regressions using a Tobit model from samples in R software 3.1.3. Linear fits represent biomarker expression levels for the proteins NGF, NSE, G-CSF, IL-4, IL-13, IL-12p70, MCP-1, LIX, and MIP-2 at each sampling time. Biomarker concentrations previously mentioned, were plotted against retinal/corneal thickness and intraocular pressure (IOP) measurements, of alike animals. Significant biomarkers which appeared to correlate with sub-lethal ocular trauma, seen in retinal thickness (RT), corneal thickness (CT), and IOP changes, were NGF, NSE, IL-4, IL-13, IL-12p70, and LIX. These findings suggest that biomarker identification may aid in the development of diagnostic tools for assessing blast injury to prevent or mitigate serious sequelae such as blindness, retinal hemorrhages, impairment of ocular movement and reflexes, and possible retinal detachment.