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Effects of lipopolysaccharide injection on in vivo breathing pattern in developing rats
Author(s) -
Johnson Rhaya L.,
Murray Samuel,
Wilson Christopher G.
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.724.4
Subject(s) - hypoxia (environmental) , lipopolysaccharide , medicine , respiratory rate , tachypnea , anesthesia , brainstem , respiratory system , endocrinology , heart rate , chemistry , oxygen , blood pressure , tachycardia , organic chemistry
Breathing pattern irregularities, which are common problems in pre‐term infants, are often exacerbated by infection. These irregularities can manifest as apneas, tachypnea, and periodic breathing. We have previously shown that lipopolysaccharide (LPS) injected into the airway of neonatal rats (postnatal days 10 to 12) causes up‐regulation of early pro‐inflammatory cytokines and blunts the response to an acute hypoxia challenge. Furthermore, we are using vagal nerve stimulation (VNS), an FDA approved treatment for epilepsy and depression, in an effort to reduce neuroinflammation in the brainstem regions for respiratory control. We have assessed cytokine expression in response to LPS injection using immunohistochemistry and mRNA quantification in nTS, XII, PBC. Our preliminary data suggests that LPS injection causes a blunted hypoxic ventilatory response to 10% oxygen (10 min, balance N 2 ). Sham animals had a 46% increase in breath rate from normoxia to hypoxia, whereas LPS animals only had a 26% increase in breath rate from normoxia to hypoxia (n = 3 for each). LPS injection also significantly increases the expression of IL‐6 (p < 0.001) and is hypothesized to increase TNFa and IL‐1b in the respiratory control regions of the brainstem. VNS slows the baseline breath rate (13% lower than sham) over the two hour recovery period. The hypoxic ventilatory response begins to recover (31% change from normoxia to hypoxia) though the increase in breath rate with hypoxia is not as large as with sham animals. VNS does reduce cytokines IL‐6 and TNFa (p<0.5) in the nTS and XII.