Table 4.
Summary of experimental variables and motor deficit outcomes in bTBI.
| Behavior test | Rodent used | Position of animal | Head restraint | Gas used in blast tube | Blast pressure | Duration of deficits | References |
|---|---|---|---|---|---|---|---|
| Staircase test | ICR Mice (25–30 g) |
4 and 7 m away from detonation source | No (animals were fixed in position with plastic net) | 500 g TNT | Shockwave and reflected wave 2.5 Psi or 5.5 Psi | Up to 7 days only in the 2.5 Psi group. No deficits were observed at 30 days for both groups | (12) |
| Ladder test | Male SD rats (250g) | 1.09 m inside the shock tube facing impact | Yes. No information on head restraint | Compressed helium | 97, 117, 153 kPa | No deficits were observed at 3, 6, 48 or 72h post blast | (17) |
| Beam walk task | SD rats (250–350 g) | Transverse prone position across the mouth of the blast tube. | Yes | Compressed air | 114, 126, and 147 kPa | Up to 3 days | (30) |
| SD rats (200–250 g) | Prone position 20cm from the end of the tube facing the blast wave | No | Compressed air | 74 kPa | No deficits up to 14 days post blast. | (63) | |
| Beam walk/ Beam balance test | Adult male SD (350-480g) | Transverse prone position with the head perpendicular to the direction of the shockwave. | Yes | Compressed air | 135 ±12.4 kPa with a mean duration of 3.50 ±0.063 ms | No significant deficits 1–5 days post blast. | (105) |
| Photo beam walk | Male SD 350 g rats |
Outside the blast tube with the right side of head perpendicular to the blast front. | No | Compressed nitrogen gas. | Reflected pressures of 31.47, 50.72, and 72.05 in <3 ms | At 24 h for all blast groups | (106) |
| Beam balance test | LE rats (250–−300 g) | 18 inches inside the shock tube, both facing and sideways to the blast | Yes | Compressed air | 36.6, 74.5, and 116.7 kPa | No deficits in the 36.6 and 74.5 kPa rats in both orientations. The rats in frontal orientation at 116.7 kPa showed significant deficits at 30 min which resolved by 2 h. Side-oriented rats had deficits at 30 min and 2 h that was resolved by 6 h |
(18) |
| Male Wistar rats (408.3 ± 93g) | Right side of the front cortex is aligned to the impact | Yes | Lithotripsy machine fired 5 shockwave pulses with 60 Hz frequency | n/a | Up to 7 days post impact | (81) | |
| Heterozygous WldS mice (8-week-old) | 10 cm from Mylar membrane with the left side of head facing the blast | No | Compressed air | 27kPa | Day 28 post blast | (55) | |
| Rotarod test | Male C57/Bl6 mice (3–4 months; 25.22 ± 1.96 g) | Supine position, 53 cm from driven section opening | Yes | Helium | Rupture pressure of 183kPa(mild) or 213 kPa (moderate) | Up to day 14 but not on days 21 and 30 in both groups | (16) |
| Male C57BL/6J mice (8–10 weeks old; 22–26 g) | 2.5 feet inside the open end of the expansion chamber, perpendicular to the direction of the shock wave | Yes | Compressed air | Two 20.6 Psi blasts separated by a min and a third blast 30 min later | Significant deficits in single and repetitive blast animals at 10 rpm, 2 and 24 h post blast.At 20 rpm, single blast animals had deficits up to 72 h and multiple impact animals up to 120 h. | (107) | |
| Adult C57BL/6 mice (12–16 weeks) | 1 cm outside exit end of blast tube facing head front. | Experiments were conducted with both head restrained and unrestrained | Helium | Mild blast of 215 ± 13 kPa, 46 ± 5kPa * ms impulse or moderate blast of 415 ± 41 kPa, 148 ± 12 kPa * ms impulse | No deficits in both groups of blast animals up to 3 days post blast | (66) | |
| LE rats (250–350 g, 10 weeks old) | 30 cm inside the shock tube with head facing the blast exposure | Yes | Compressed air | 74.5 kPa for 3 days | No motor deficits were observed in rotarod at 8 weeks post blast. | (50) | |
| SD rats (300 g) | At 19 cm from the nozzle opening at an angle of 21° from the vertical axis of the shock tube. | Not mentioned | Nitrogen gas | 28 kPa | Up to 9 days post blast | (86) | |
| SD rats (200–250 g) | Prone position 20 cm from the end of the tube facing the blast wave | No | Compressed air | 74 kPa | No deficits up to 14 days post blast. | (63) | |
| Male Wistar rats (408.3 ± 93g) | Right side of the front cortex is aligned to the impact | Yes | A lithotripsy machine fired 5 shockwave pulses with 6o Hz frequency | n/a | Up to 7 days post impact | (81) | |
| Open Field Test (OFT) |
SD rats | 39 and 17 cm outside shock tube opening, 40 and 20° lateral to shock tube axis, respectively | yes | Helium | 100 and 450 kPa reflected peak overpressure | At 4 days and 30 days post impact in both blast groups | (46) |
| SD rats (~300 g) | Transverse prone position across the mouth of the blast tube. | Yes, with chest protection and head exposed | Compressed air | 20.6 ± 3 psi | Higher resting times at day 45 post injury. | (56) | |
| Adult C57BL/6 mice (12–16 weeks) | 1 cm outside exit end of blast tube facing head front. | Experiments were conducted with both head restrained and unrestrained | Helium | Mild blast of 215 ± 13 kPa, 46 ± 5 kPa * ms impulse or moderate blast of 415 ± 41 kPa, 148 ± 12 kPa * ms impulse | At day 4 post blast in both groups. | (66) | |
| C57BL/6J mice (2-month-old) | Prone position 3, 4, and 7 m distances away from the source with the head longitudinally aligned to the shockwave propagation | No | C4 explosives | ~46.6 kPa, ~31.9 kPa and ~19.6 kPa corresponding to 3, 4, and 7 m distances from source. | At 3 days post injury in the 3, 4, and 7 m blast group | (58) | |
| LE rats (250–350 g, 10 weeks old) | 30 cm inside the shock tube with head facing the blast exposure | Yes | Compressed air | 74.5 kPa for 3 days | No motor deficits at 7 weeks post blast. | (50) | |
| LE rats (250–350 g, 10–12 weeks old) | Head facing the shockwave exposure | Yes | Compressed air | One 74.5 kPa exposure for 3 consecutive days | No deficits 11 weeks post blast | (62) | |
| SD rats (300–330 g) | Transverse prone position across the mouth of the blast tube. | Yes. Chest protection with rat head exposed | Compressed air | 138 kPa single or 5 blasts | At day 1 but not on day 16 in multiple impact group. | (19) | |
| C57BL/6 Mice (2.5 months) | 0.56 m inside open exit of shock tube | Both with and without head restraint | Compressed gas | 77 ± 2 kPag | No deficits | (26) | |
| LE rats (250 g−350 g; 10 weeks of age) | Head facing the blast exposure | Yes | Compressed air | 74.5kPa | At 28 weeks post blast | (65) | |
| Elevated plus maze | SD rats (~300 g) | Transverse prone position across the mouth of the blast tube. | Yes with chest protection and head exposed | Compressed air | 20.63 psi | At day 44 post blast but not at days 15 or 66. | (57) |
| SD rats (245–265 g) | Transverse prone position across the mouth of the blast tube. | Yes, with chest protection and head exposed | Compressed air | 20.63 psi | Immediately after blast. | (82) |