Lipopolysaccharide (LPS)는 염증유발 cytokine 분비를 자극하고 염증을 유발하는 그람음성균의 내독소이다. 본 연구에서는 LPS가 신경아교세포 활성과 해마에 있는 nuclear factor kappa B (NF-κB) 매개 염증유발 요소를 조절하는지를 조사하였다. 성체 수컷 쥐를 대조군과 LPS를 투여한 실험군으로 무작위로 나누어 vehicle 또는 LPS (250 μg/kg)를 5일 동안 복강투여하고 무게를 측정했다. 해마의 활성산소와 과산화지방질 수준을 분석하고, 형태학적 연구를 위해 Hematoxylin and eosin 염색을 시행하였다. 또한, 해마에서 ionized calcium-binding adapter molecule 1 (Iba-1), glial fibrillary acidic protein (GFAP), NF-κB, interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α)의 발현을 확인하기 위해 Western blot 분석과 immunofluorescence 염색을 시행하였다. 그 결과, LPS를 투여한 쥐들의 체중이 감소하였다. LPS 투여는 활성산소와 과산화지방질 수준의 증가를 유발하였고 LPS를 투여한 쥐의 해마에서 심각한 조직병리학적 변화를 확인했다. 또한 LPS 투여는 신경교세포와 별아교세포의 표시물인 Iba-1과 GFAP의 발현을 증가시켰고, NF-κB의 발현과 IL-1β와 TNF-α와 같은 염증성인자의 발현을 증가시켰다. 이러한 결과들을 통해 LPS 투여는 해마손상과 염증반응을 유도한다는 것을 알 수 있고 LPS 투여가 해마조직에서 신경아교세포와 NF-κB에 매개된 염증인자들을 활성화시킨다는 것을 확인하였 다. 따라서, 본 연구는 LPS 투여는 해마조직에서 산화적 스트레스 증가와 염증인자 활성을 증가시켜 신경손상을 유도함을 보여준다.

Lipopolysaccharide (LPS) is the endotoxin of Gram-negative bacteria that stimulates inflammatory cytokine release and induces inflammation. In the present study, we investigated whether LPS regulates neuroglial cell activation and nuclear factor kappa B (NF-κB)-related inflammatory factors in the hippocampus. Adult male mice were randomly grouped as control animals and LPS-treated animals. Mice were intraperitoneally injected with vehicle or LPS (250 μg/kg) for 5 days and body weight was measured. Reactive oxygen species and lipid peroxidation levels in the hippocampus were analyzed. Hematoxylin and eosin staining was performed for the morphological study. Western blot analysis and immunofluorescence staining were carried out to examine the expression of ionized calcium-binding adapter molecule 1 (Iba-1), glial fibrillary acidic protein (GFAP), NF-κB, interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) in the hippocampus. Body weight was reduced in LPS-treated animals. LPS treatment induced increases in reactive oxygen species and lipid peroxidation levels. We confirmed severe histopathological changes in the hippocampi of LPS-treated animals. We also observed that LPS treatment increases Iba-1 and GFAP expression levels. Iba-1 and GFAP are used as markers of microglia and astrocyte activation, respectively. Moreover, LPS administration increased NF-κB expression and up-regulated pro-inflammatory factors, including IL-1β and TNF-α. These results indicate that LPS promotes an inflammatory response and leads to hippocampal damage. Thus, we demonstrated that LPS induces neuroglial cells activation and increases NF-κB-mediated inflammatory factors in the hippocampus. In conclusion, our findings suggest that LPS leads to neurotoxicity by up-regulating oxidative stress and activating inflammatory factors in the hippocampus.

초록
ABSTRACT
서론
재료 및 방법
    1. 실험동물 및 LPS 투여
    2. Reactive oxygen species (ROS) 측정
    3. Lipid peroxidation (LPO) 측정
    4. Hematoxylin & eosin 염색
    5. Western blot 분석
    6. 면역형광 염색
    7. 자료 분석
결과 및 고찰
    1. LPS투여에 의한 체중 감소 및 ROS과 LPO의수치 증가
    2. LPS투여에 따른 해마조직의 조직병리학적 변화
    3. LPS투여에 따른 해마조직의 Iba-1과 GFAP의발현량의 변화
    4. LPS투여에 따른 해마조직의 NF-κB, IL-1β,TNF-α의 단백질 발현량의 변화
References

• 강주빈(경상대학교 수의과대학 수의학과) | Ju-Bin Kang (Department of Veterinary Medicine, College of Veterinary Medicine, Gyeongsang National University)
• 박동주(경상대학교 수의과대학 수의학과) | Dong-Ju Park (Department of Veterinary Medicine, College of Veterinary Medicine, Gyeongsang National University)
• 고필옥(경상대학교 수의과대학 수의학과/경상대학교 농업생명과학연구원) | Phil-Ok Koh (Department of Veterinary Medicine, College of Veterinary Medicine, Gyeongsang National University/Institute of Agriculture and Life Science, Gyeongsang National University) Corresponding author