Biologic Effect of Hydrogen Sulfide and Its Role in Traumatic Brain Injury

Table 1

Characteristics of different degrees of TBI in different species.

Species
Human	Mild TBI; (1) Any period of loss of consciousness up to 30 min; (2) Posttraumatic amnesia not exceeding 24 h; (3) Any period of confusion or disorientation; (4) Transient neurological abnormalities; (5) A GCS score of 13–15; (6) Normal structural imaging; (7) Postconcussion symptoms may resolve during 12 weeks
	Moderate TBI; (1) A possible loss of consciousness lasting up to a few hours; (2) Confusion lasting from days to weeks; (3) Physical, cognitive, and/or behavioral impairments lasting for months; (1) Abnormal structural imaging; (2) A GCS score of 9–12
	Severe TBI; (1) Sustained loss of consciousness (>24 h); (2) Surviving patients exhibiting chronic physical and emotional disabilities; (3) Abnormal structural imaging; (4) A GCS score of less than 9
Mouse	Mild TBI; (1) CCI: depth: 0.1–1.0 mm; velocity: 3.0–6.0 m/s; (2) Tissue loss: lesions confined to the cortical layer; (3) Cortical depression <0.5 mm, velocities <4.0 m/s
	Moderate TBI; (1) CCI: depth: 0.5–3.0 mm; velocity: 1.5–6.0 m/s; (2) Tissue loss: considerable cortical tissue loss with little to no overt hippocampal loss; (3) Cortical depression 1.0–1.5 mm, velocities 4.0–5.0 m/s
	Severe TBI; (1) CCI: depth: 0.5–2.0 mm; velocity: 3.0–6.0 m/s; (2) Tissue loss: extensive overt hippocampal lesions along with cortical tissue loss; (3) Cortical depression >2.0 mm, velocities >5.0 m/s

Note: TBI: traumatic brain injury; CCI: controlled cortical impact; GCS: the Glasgow Coma Scale.