A major inflammatory cytokine TNF-a inhibits the ventilatory response to hypoxia

It is known that the systemic level of the major pro-inflammatory cytokine increases in many respiratory diseases such as asthma, COPD and sleep apnea. The lung ventilation changes and the pathological types of breathing are typical in these diseases. By the reason, the increasing cytokine level research is actual.The aim of the present study was to examine the hypothesis that elevation of major pro-inflammatory cytokine TNF-α systemic level may decrease the ventilatory response to hypoxia.The experiments were performed in tracheostomized anaesthetized rats. The hypoxic ventilatory response was measured by using rebreathing with hypoxic gas mixture before and after the tail vein injection of TNF-α(10mcg/rat).We have shown that the increase in level of TNF-α in blood weakens the ventilatory responses to hypoxia. The slope of the hypoxic ventilatory response decreased from 6.06±0.91 to 3.48±0.38 mL/min–1 mmHg–1 (-40%) 40 min after administration of TNF-α(p<0.05), the slope of tidal volume and mean inspiratory flow also decreased by -27% and -27% respectively(p<0.05). When the resting breathing basal level of lung ventilation in contrary increased after elevate of TNF-α level in the blood.We concluded that the elevation of inflammatory cytokine level in blood intensifies ventilation during the resting breathing that may be associated with increased central inspiratory activity. At the same time TNF-α reduces the...
Source: European Respiratory Journal - Category: Respiratory Medicine Authors: Tags: Mechanisms of Lung Injury and Repair Source Type: research