[Effects of polymyxin B on LPS-induced activation of NF-kappaB in pulmonary alveolar macrophages].
OBJECTIVE
To observe effects of polymyxin B (PMB) on LPS-induced activation of NF-kappaB of pulmonary alveolar macrophages(PAMs) and explore the possible anti-inflammation efficiency of PMB.


METHODS
Rat PAMs were isolated and cultured. The PAMs were divided into 3 groups, namely, normal control group (PAMs+normal solution), LPS stimulation group (PAMs+10 mg/L LPS) and PMB interference group(after PMB treatment for 30 min, using LPS stimulation). The PAMs were fixed respectively at 0,15,30,60,120 and 240 min after stimulation. Nucleoprotein was extracted from cultured PAMs and culture supernatant of the PAMs was collected. The expression of IKK-beta mRNA in the PAMs, NF-kappaB activity in PMB nucleoprotein extractive, TNF-alpha content in culture supernatant of the PAMs were detected by in situ hybridization (ISN), electrophoretic mobility shift assay (EMSA) and ELISA, respectively.


RESULTS
IKK-beta mRNA level in LPS group increased at 15 min, reached the peak at 30 min, while IkappaB-alpha level turned out contrary to IKK-beta mRNA level. The peak of NF-kappaB activity appeared at 60-120 min after stimulation was significantly higher than those of pre-stimulation and normal control group (P<0.01). In PMA interference group, NF-kappaB activity and TNF-alpha level were markedly lower than those in LPS stimulation group (P<0.01). The lowest level of IkappaB-alpha was notably higher than that in LPS stimulation group, while the peak of IKK-beta mRNA was obviously lower than that in LPS stimulation group (P<0.01).


CONCLUSIONS
LPS can induce IKK-beta and NF-kappaB activation, IkappaB-alpha degradation, accelerate TNF-alpha release, but PMB can counteract those effects induced by LPS stimulation.
Yang
Jian-Hong
JH
Department of Emergency, Xijing Hospital, Fourth Military Medical University, Xi'an 710032,China.
Yin
Wen
W
Yuan
Jing
J
Li
Yue-Cai
YC
D000818:Animals; D051550:I-kappa B Kinase; D008070:Lipopolysaccharides / Q000494:pharmacology; D016676:Macrophages, Alveolar / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D011112:Polymyxin B; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D008070:Lipopolysaccharides; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D051550:I-kappa B Kinase; D011112:Polymyxin B