Korean J Physiol Pharmacol.  2018 May;22(3):301-309. 10.4196/kjpp.2018.22.3.301.

Atorvastatin pretreatment attenuates kainic acid-induced hippocampal neuronal death via regulation of lipocalin-2-associated neuroinflammation

• Jin Z
• Jung Y
• Yi CO
• Lee JY
• Jeong EA
• Lee JE
• Park KJ
• Kwon OY
• Lim BH
• Choi NC
• Roh GS

• KMID: 2410094
• DOI: http://doi.org/10.4196/kjpp.2018.22.3.301

Abstract

Statins mediate vascular protection and reduce the prevalence of cardiovascular diseases. Recent work indicates that statins have anticonvulsive effects in the brain; however, little is known about the precise mechanism for its protective effect in kainic acid (KA)-induced seizures. Here, we investigated the protective effects of atorvastatin pretreatment on KA-induced neuroinflammation and hippocampal cell death. Mice were treated via intragastric administration of atorvastatin for 7 days, injected with KA, and then sacrificed after 24 h. We observed that atorvastatin pretreatment reduced KA-induced seizure activity, hippocampal cell death, and neuroinflammation. Atorvastatin pretreatment also inhibited KA-induced lipocalin-2 expression in the hippocampus and attenuated KA-induced hippocampal cyclooxygenase-2 expression and glial activation. Moreover, AKT phosphorylation in KA-treated hippocampus was inhibited by atorvastatin pretreatment. These findings suggest that atorvastatin pretreatment may protect hippocampal neurons during seizures by controlling lipocalin-2-associated neuroinflammation.

Keyword

Atorvastatin; Hippocampal cell death; Kainic acid; Lipocalin-2; Seizures

MeSH Terms

Animals
Atorvastatin Calcium*
Brain
Cardiovascular Diseases
Cell Death
Cyclooxygenase 2
Hippocampus
Hydroxymethylglutaryl-CoA Reductase Inhibitors
Kainic Acid
Mice
Neurons*
Phosphorylation
Prevalence
Seizures
Atorvastatin Calcium
Cyclooxygenase 2
Kainic Acid

Figure

• 

  Fig. 1 Effect of KA treatment on hippocampal LCN2 expression in mice.(A) Western blot showing altered LCN2 expression in KA-treated hippocampus. The hippocampal LCN2 expression appeared 6 h after KA treatment. (B) Quantitative expression of LCN2 protein from the western blot analysis. Densitometric values for LCN2 were normalized to β-actin levels. The mean values were obtained from two separate experiments (n=5-6 mice per group). Data are shown as mean±SEM. *p<0.05 vs. KA.

• 

  Fig. 2 Effect of atorvastatin pretreatment on seizure activity and hippocampal cell death in KA-treated mice.At 24 h after KA systemic injection, seizure activity was scored during the 2 h observation period. Behavioral seizure scores (A) and percentage of survival (B) in KA-treated mice with or without AS are shown. Data (n=15 mice per group) are shown as mean±SEM. *p<0.05 vs. KA. (C) Representative microphotographs of cresyl violet-stained sections and immunofluorescent images of TUNEL-stained sections in CA3 regions. The boxed area of cresyl violet-stained images is magnified in the center panel. Scale bar=50 mm.

• 

  Fig. 3 Effect of atorvastatin pretreatment on LCN2 expression in KA-treated hippocampus.(A) Western blots show hippocampal LCN2 expression 24 h after KA treatment. Densitometric values of LCN2 expression from three separate experiments (n=6–7 mice per group) were normalized to β-actin levels. *p<0.05 vs. CTL. †p<0.05 vs. KA. Representative images of double-immunofluorescence staining for LCN2 (red) and GFAP (green) (B) and LCN2 (red) and Iba-1 (green) (C) in the CA3 region of CTL, KA, KA+AS, and AS mice. Scale bar=50 µm.

• 

  Fig. 4 Effect of atorvastatin pretreatment on neuroinflammation in KA-treated hippocampus.(A) Western blots show hippocampal COX-2 expression 24 h after KA treatment. Densitometric values of COX-2 expression from three separate experiments (n=6–7 mice per group) were normalized to β-actin levels. *p<0.05 vs. CTL. †p<0.05 vs. KA. (B) Representative images of immunostained COX-2 in the hippocampus of CTL, KA, KA+AS, and AS mice. The boxed area of each image is magnified in the lower panel. Scale bar=50 mm. (C) Western blots show hippocampal GFAP (C) and Iba-1 (D) expression 24 h after KA treatment. Densitometric values (n=6–7 mice per group) for GFAP and Iba1 were normalized to β-actin levels. *p<0.05 vs. CTL. †p<0.05 vs. KA-treated mice.

• 

  Fig. 5 Effect of atorvastatin pretreatment on AKT phosphorylation in KA-treated hippocampus.(A) Western blot shows p-AKT and AKT expression in KA-treated hippocampus. (B) Quantitative expression of p-AKT and AKT protein from the western blot analysis. Densitometric values of expression of each protein from three separate experiments (n=6–7 mice per group) were normalized to β-actin levels. Data are shown as mean±SEM. *p<0.05 vs. CTL. †p<0.05 vs. KA-treated mice.

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