Table 1.
Overview of in vivo Studies Investigating the Role of Zinc during Cerebral Ischemia
| Species/Model | Therapeutic Intervention | Assessment Methods/Main Finding(s) | Reference |
|---|---|---|---|
| Rat/Global ischemia; 4-VOa (20 min occlusion). | – | TSQb & acid fuschin staining between 2 and 24 h post-ischemia/At 2 h: TSQ-stained somata in CA4, diminished TSQ-signal in mossy fibers; at 18 h: TSQ-stained cells corresponded to acidophilic cells. | (9) |
| Rat/Focal ischemia; tMCAOc (60 min occlusion). | ZnPPd (1–10 μg); topical application. | Brain edema (wet/dry weight method) assessed at 24 h post-ischemia/Modest but significant reduction in brain edema with ZnPP treatment. | (24) |
| Rat/Global ischemia; 4-VO (20 min occlusion). | Pre-txe & intra-txf hypothermia (29°C) started 1h prior and maintained for ischemia. | TSQ staining 2 h to 7 days post-ischemia/Ischemia at 37°C: TSQ-stained CA3 neuronal bodies present at 2 to 24 h; ischemia at 29°C: TSQ-stained cell bodies absent. | (10) |
| Rat/Focal ischemia; pMCAOg or tMCAO (2 h occlusion). | ZnPP (50 mg/kg) i.p., pre-tx: 30 min(pMCAO & tMCAO); post-txh: 2 or 4 h (tMCAO). | Infarct volume & brain edema assessed 24 h post-ischemia/ZnPP pre-tx in pMCAO: no effect; ZnPP post-tx in tMCAO: no effect; ZnPP pre-tx in tMCAO: dramatic neuroprotective effect reducing infarct volume & brain edema. | (26) |
| Rat/Global ischemia; 2-VOi (15 min occlusion). | Ca-EDTA 300 mM (5 μL; i.c.v.), pre-tx: 30 min. | TSQ & acid fuschin staining 72 h post-ischemia/Znj accumulation leads to degeneration; Ca-EDTA reduced Zn accumulation & degeneration of CA1 neurons. | (11) |
| Rat/Focal ischemia; tMCAO (2 h occlusion) | ZnCl2k (10 mg/kg; i.p.), PPl (48.5 mg/kg; i.p.), ZnPP (50 mg/kg; i.p.), pre-tx: 30 min. | Infarct volume & brain edema assessed 24 h post-ischemia/ZnCl2 reduced infarct volume but had no effect on brain edema; ZnPP and PP: both significantly reduced infarct volume and brain edema. | (27) |
| Gerbil/Global ischemia; BCCAOm (3 min occlusion). | ZnCl2 (20 mg/kg; s.c), pre-tx: 1 h, or 48 and 24 h. | TUNELn and H-Eo at 3 and 4 days, respectively/1 h ZnCl2 pre-tx: no effect; 48 and 24 h ZnCl2 pre-tx: modest but significant protection of CA1 region. | (28) |
| Gerbil/Global ischemia; BCCAO (5 min occlusion). | – | Examined ZnT-1 mRNA expression between 12 h to1 week post ischemia/ZnT-1 mRNA expression was induced in CA1 neurons exhibiting Zn accumulation. Without subsequent ZnT-1 protein expression, these cells started to degenerate at 72 h. | (12) |
| Rat/Focal ischemia; pMCAO. | – | Neo-Timm stain to show synaptic Zn levels from 7 min to 7 days post-ischemia/Decrease in Zn staining at 7 min and continued throughout 7 days; at 1 h, Zn-positive cell bodies seen. | (31) |
| Rat/Global ischemia; 2-VO (15 min occlusion). | Ca-EDTA 300 mM (3 μL; i.c.v.); pre-tx: 30 min. | TFL-Znp and TUNEL staining 24, 48, and 72 h post-ischemia/Ca-EDTA markedly reduced Zn accumulation and degeneration of CA1 neurons at all time points. | (14) |
| Rat/Global ischemia; 2-VO (12 min occlusion). | Sodium Pyruvate (500 mg/kg; i.p.); pre-tx: 30 min; post-tx: 08, 0.5, 1, 2, 3 h. | TFL-Zn & TUNEL staining 3, 15, and 30 days post-ischemia/Sodium pyruvate almost completely blocked neuronal injury when given within 1 h of ischemia. | (16) |
| Rat/Focal ischemia; tMCAO (30 min occlusion – mild ischemia) or (60 min occlusion – severe ischemia). | Ca-EDTA 500 mM (5 μL; i.c.v.).; pre-tx: 15 min or post-tx: continuous infusion for 1 week (10–100 nmole/h) 1 μL/h; i.c.v. | TSQ, H-E, acid fuschin, CM1-IHCr staining 3 h to 14 days post-ischemia/Ca-EDTA pre-tx reduced intracellular Zn accumulation, infarct volume, and degeneration at 3 days but protective effects lost at 14 days or if insult intensity increased (30 min occlusion to 60 min occlusion) and if Ca-EDTA was continuously infused for 7 days. | (17) |
| Mouse/Global ischemia; BCCAO (20 min occlusion). | Hypothermia (33°C) initiated at occlusion; continued 35 min. | TSQ & H-E staining 72 h post-ischemia/Hypothermia markedly reduced Zn accumulation and degeneration of CA1, CA2, and CA4 neurons. | (18) |
| Mouse/Focal ischemia photothrombosis. | – | Infarct volumes & ZnSeAMG s assessed 30 min to 24 h post-ischemia/Infarct core devoid of Zn by 0.5 h until 24 h; 20% increase in Zn in peri-infarct region up to 6 h; Lesions markedly larger at later (12 and24 h) than at earlier (0.5–6 h) times. | (33) |
| Rat/Focal ischemia; Embolic MCAO. | ZnCl2 (80μmol/kg; i.p.); Bicuculline (48.5 μmol/kg; i.p.) or the above in combination; pre-tx: 30 min. | Infarct volume & brain edema assessed 48 h post-ischemia/ZnCl2 alone or ZnCl2 and Bicuculline: dramatically increased infarct volume, increased brain edema and worsened neurological deficits; Bicuculline alone: no effect. | (19) |
| Gerbil/Focal ischemia; right pMCAO. | – | Micro-dialysis collected 0–3 h post-ischemia; analyzed with GF-AASt/Zn levels dropped 75% of baseline and never recovered in ipsilateral hemisphere and only minimally changed in contralateral hemisphere. | (35) |
| Gerbil/Global ischemia BCCAO (5 min occlusion) and Rat/Global ischemia4-VO (10 min occlusion). | Ca-EDTA 300 mM (5 μL; i.c.v.); pre-tx: 30 min or post-tx: 3, 6, 48, 60, or 72 h. | GluR2 mRNA and protein expression, Caspase-3-activity, TSQ, TUNEL48 h to 5 days post-ischemia/Ca-EDTA pre-tx: reduced Zn levels, GluR2 down-regulation, and early stages of apoptosis in CA1 cells; Ca-EDTA Post-tx between 48 and 60 h: rescued CA1 cells by blocking the later stages of apoptosis (DNA fragmentation). | (22) |
| Rabbit/Global ischemia; inflatable neck tourniquet& systemic hypoperfusion(30 min occlusion). | – | Micro-dialysis collected 4 to 6 h post-ischemia; analyzed with pZn meter/Ischemia induced immediate rise in extracellular Zn levels from baseline (19 nM) in hippocampus. Reperfusion induced greater rise in extracellular Zn levels (~100 nM). Glutamate release was earlier and shorter in duration than Zn release | (38) |
| Rat/Focal ischemia tMCAO (60 min occlusion). | Ca-EDTA 100 mM (5 μL; i.c.v.); pre-tx: 30 min | Infarct volume assessed 3, 6, & 24 h post-ischemia/Ca-EDTA pre-tx: deleterious effect on early infarct development: larger infarct volumes at 3 and 6 h but similar to control at 24 h. | (30) |
| Rat/Global ischemia 4-VO(30 min occlusion). | – | TSQ staining 0 to 24 h post-ischemia/Zn accumulation in CA1 cells at 24 h but not before. Micro-dialysis collected 0 to 3h post-ischemia; analyzed with flameless AASu. Extracellular Zn levels in CA1 area increased to~600 nM within 15 min of occlusion, decreased during reperfusion, and returned to basal levels (~300 nM). | (36) |
| Rat/Focal ischemia tMCAO(60 min occlusion). | – | Micro-dialysis collected 0 to 3 h post-ischemia; analyzed with flameless AAS/Extracellular Zn levels increased to ~300 nM within 15 min of occlusion, decreased during reperfusion, and returned to basal levels (~150 nM). | (37) |
a
4-VO, 4-vessel occlusion.
b
TSQ, N-[6-methoxy-8-quinolyl]-P-toluenesulfonamide.
c
tMCAO, transient middle cerebral artery occlusion.
d
ZnPP, zinc protoporphyrin.
e
pre-tx, pre-treatment.
f
intra-tx, intra-treatment.
g
pMCAO, permanent middle cerebral artery occlusion.
h
post-tx, post-treatment.
i
2-VO, 2-vessel occlusion.
j
Zn, zinc.
k
ZnCl2, zinc chloride.
l
PP, protoporphyrin.
m
BCCAO, bilateral common carotid occlusion.
n
TUNEL, Terminal Deoxynucleotidyl Transferase Mediated dUTP Nick End Labeling.
o
H-E, hematoxylin and eosin stain.
p
TFL-Zn, N-(6-methoxy-8quinolyl)-P-carboxybenzoylsulfonamide.
q
“0” hr refers to the time coinciding with the onset of reperfusion
r
CM1-IHC, antibody against activated caspase-3 immunohistochemistry.
s
ZnSeAMG, zinc-selenium autometallography technique.
t
GF-AAS, graphite furnace atomic absorption spectroscopy.
u
AAS, atomic absorption spectroscopy.