ABSTRACT
Objective:
To evaluate the effect of
sleep deprivation on
cognitive function in septic
rats and its relationship with neuronal
glycolysis isoenzyme phosphofructokinase-2/
fructose-2,?6-diphosphatase 3 (PFKFB3).
Methods:
Fifty-six healthy
male Sprague-Dawley (SD)
rats were randomly divided into 4 groups ( n = 14)
control group (Con group),
sepsis group (LPS group),
sepsis+
sleep deprivation group (LPS+SD group),
sepsis+
sleep deprivation+
glycolysis inhibitor 3-PO
treatment group (LPS+SD+3-PO group). The
sepsis model was established by
intraperitoneal injection of
lipopolysaccharide (LPS) 10 mg/kg.
Rats in LPS+SD group were treated with
sleep deprivation using a
sleep deprivation instrument 24 hours after LPS
injection. The LPS+SD+3-PO group was intraperitoneally injected with LPS for 24 hours, and then injected with 3-PO 50 mg/kg, followed by
sleep deprivation. Novel object recognition experiments were performed 72 hours after LPS
injection. Subsequently,
blood and
brain tissue samples were collected. The contents of
lactate (Lac),
reactive oxygen species (ROS) and
serum tumor necrosis factor-α(TNF-α),
neuron-specific enolase (NSE),
pyruvate in
brain tissue were detected by
enzyme-linked immunosorbent assay (
ELISA). Then, the
lactate/
pyruvate ratio was calculated. Na +-K +-
ATPase activity in
brain tissue was detected by
colorimetry. Morphological changes in
hippocampus were detected by
hematoxylin-
eosin (HE)
staining. And the
protein expression levels of PFKFB3, ZO-1 and cleaved
caspase-3 were measured by
Western blotting.
Results:
Compared with Con group, the novel object recognition index of LPS group was decreased, the levels of NSE, TNF-α,
lactate/
pyruvate ratio in
serum and the levels of Lac, ROS and dry-wet weight ratio in
brain tissue were significantly increased, Na +-K +-
ATPase activity in
brain tissue was decreased, the
protein expressions of PFKFB3,
caspase-3 were up-regulated, ZO-1 expression was down-regulated, and the
neurons in
hippocampus were slightly degenerated. Compared with LPS group, the novel object recognition index of LPS+SD group was further decreased [(39.4±5.3)% vs. (54.5±7.6)%)],
serum NSE, TNF-α,
lactate/
pyruvate ratio and
brain tissue Lac, ROS, dry-wet weight ratio were further increased [NSE (μg/L) 3.21±0.42 vs. 2.55±0.36, TNF-α (ng/L) 139.4±19.7 vs. 92.2±13.5,
lactate/
pyruvate ratio 29.7±5.5 vs. 19.2±4.2, Lac (μmol/g) 19.51±2.33 vs. 11.34±1.52, ROS (kU/g) 117.4±18.7 vs. 78.2±11.8, dry-wet weight ratio (81.3±9.2)% vs. (64.3±6.6)%], and Na +-K +-
ATPase activity was further decreased (mmol·L -1·h -1 1.88±0.34 vs. 2.91±0.39), the
protein expressions of PFKFB3,
caspase-3 were further up-regulated and ZO-1 expression was further down-regulated (PFKFB3/β-
actin 0.80±0.11 vs. 0.45±0.07,
caspase-3/β-
actin 0.71±0.09 vs. 0.37±0.05, ZO-1/β-
actin 0.31±0.05 vs. 0.61±0.08). The differences were statistically significant (all P < 0.05). HE
staining showed that the degeneration of
neurons in
hippocampus was significantly aggravated. Compared with LPS+SD group, the novel object recognition index of LPS+SD+3-PO group was increased [(50.8±5.9)% vs. (39.4±5.3)%], NSE, TNF-α,
lactate/
pyruvate ratio of
serum and Lac, ROS, dry-wet weight ratio of
brain tissue were significantly decreased [NSE (μg/L) 2.60±0.33 vs. 3.21±0.42, TNF-α (ng/L) 103.7±18.3 vs. 139.4±19.7,
lactate/
pyruvate ratio 17.4±5.1 vs. 29.7±5.5, Lac (μmol/g) 13.68±2.02 vs. 19.51±2.33, ROS (kU/g) 86.9±14.5 vs. 117.4±18.7, dry-wet weight ratio (67.7±6.9)% vs. (81.3±9.2)%], and Na +-K +-
ATPase activity was increased (mmol·L -1·h -1 2.82±0.44 vs. 1.88±0.34). The
protein expressions of PFKFB3,
caspase-3 were down-regulated and ZO-1 expression was up-regulated (PFKFB3/β-
actin 0.50±0.06 vs. 0.80±0.11,
caspase-3/β-
actin 0.43±0.06 vs. 0.71±0.09, ZO-1/β-
actin 0.52±0.06 vs. 0.31±0.05). The differences were statistically significant (all P < 0.05). HE
staining showed that the degeneration of
neurons in
hippocampus was significantly improved.
Conclusions:
Sleep deprivation could aggravate
neuroinflammation, neuronal degeneration and
apoptosis in septic
rats, resulting in destruction of
blood-brain barrier and
cognitive impairment. 3-PO
treatment significantly alleviate the
injury and degeneration of hippocampal
neurons in septic
rats, inhibit
neuroinflammation and
apoptosis, and improve
cognitive dysfunction, which may be related to the inhibition of glycolytic
isoenzyme PFKFB3.