D-allose inhibits TLR4/PI3K/AKT signaling to attenuate neuroinflammation
and neuro-specific apoptosis via inhibiting Gal-3 following ischemic
stroke
Abstract
Background: Ischemic stroke (IS) occurs when a vessel supplying blood to
the brain is obstructed. Our previous study showed that D-allose exerts
neuroprotective effects against acute cerebral ischemic/reperfusion
(I/R) injury by reducing neuroinflammation. Here, we aim to clarify the
beneficial effects and underlying mechanism of D-allose in suppressing
IS-induced neuroinflammation damage, cytotoxicity and neuro-specific
apoptosis and neurological deficits in vitro and in vivo. Methods: For
in vivo study, the I/R model was induced by middle cerebral artery
occlusion and reperfusion (MCAO/R) in C57BL/6J mice and D-allose was
given intraperitoneal injection within 5min after reperfusion. In vitro,
mouse hippocampal neuronal cells (HT22) with oxygen–glucose deprivation
and reperfusion (OGD/R) were established as the cell model of IS. The
neurological score evaluation, some cytokines, cytotoxicity and
apoptosis in the brain and cell lines were measured. Moreover, Gal-3
short hairpin RNA, lentivirus and adeno-associated virus were employed
to modulate Gal-3 expression in neuronal both in vitro and in vivo to
reveal the molecular mechanism. Results: D-allose alleviated
cytotoxicity, including cell viability, LDH release and apoptosis in
HT22 cells after OGD/R, which also relieved brain injury, such as lesion
volume, brain edema, neuronal apoptosis, as well as neurological
functional deficits in a mouse model of I/R. Importantly, loss of Gal-3
enhanced the D-allose’s protection against I/R-induced HT22 cell injury,
inflammation insults and apoptosis, whereas activation of TLR4 by
selective agonist LPS increased the degree of injury of neuron, as well
as abolished the protective effects of D-allose.