Correlation analysis of LXR and its target genes COX2 and CETP with the severity of OSAHS in obese young rats

To analyse the relationships between the expression levels of liver X receptor (LXR), cyclooxygenase-2(COX2) and cholesterol ester transfer protein (CETP) and the severity of obstructive sleep apnoea hypopnoea syndrome (OSAHS) in obese young rats, to obtain information for basic research on OSAHS in obese children.

Twenty-four 3-4-week-old young rats were randomly assigned to the normal control group, obesity group, OSAHS group, obesity and OSAHS group. We used polysomnography to measure the obstructive apnoea hypopnoea index (OAHI) to assess the severity of OSAHS and western blotting to test the expression levels of LXRα, COX2, and CETP in the liver, heart, kidney, and brain tissues.

LXR, COX2, and CETP expression levels in the remaining groups were considerably higher than those in the control group (P < 0.05). Compared with those in the obesity group, LXRα, COX2, and CETP expression levels in the obesity and OSAHS group were considerably greater in the liver, kidney, and heart tissues (P < 0.05); the brain tissues of the obesity and OSAHS group showed considerably higher expression levels of COX2 and CETP (P < 0.05). Compared with those in the OSAHS group, LXRα, COX2, and CETP expression levels in the obesity and OSAHS group were significantly greater in all tissues (P < 0.05). The expression levels of LXRα, COX2, and CETP and obesity increased with increasing OSAHS severity (r = 0.777, P < 0.01; r = 0.728, P < 0.01; r = 0.793, P < 0.01; r = 0.786, P < 0.01; and r = 0.698, P < 0.01), and the oxygen concentration increased with decreasing OSAHS severity(r=-0.576, P < 0.01).

LXR, COX2, and CETP expression levels were significantly increased in the liver, kidney, heart, and brain tissues of young rats with obesity and OSAHS, and were positively correlated with the severity of OSAHS.