CCK-8 inhibit expression of TNF-α in the spleen of endotoxic shock rats and sigual transduction mechanism of p38 MAPK

AIM: To study the effect of sulfated cholecystokinin-octapeptide (CCK-8) on systemic hypotension, gene and protein expression of TNF-alpha, in spleen of lipopolysaccharide (LPS)-induced endotoxic shock (ES) rats, and further investigate the signal transduction mechanism of p38 mitogen-activated protein kinase (MAPK). METHODS: The changes of blood pressure were observed using physiological record instrument in four groups of rats: LPS (8 mg . kg(-1), iv), CCK-8 (40mug . kg(-1), iv) pretreatment 10 min before LPS (8 mg . kg(-1)), CCK-8 (40mug . kg(-1), iv) or normal saline ( control) group. The content of TNF-alphain spleen was assayed 2 h after LPS administration using ELISA kit and the expression of TNF-alpha mRNA was examined 30 min, 2 h and 6 h after LPS administration by reverse transcribed polymerase chain reaction (RT-PCR). Activation of p38 MAPK was detected with Western blot 30 min after LPS administration. RESULTS: CCK-8 reversed LPS-induced decrease of mean arterial pressure MAP) in rats. The content of TNF-alpha in spleen was (282 +/- 30) ng . L-1 in control group, while it increased to (941 +/- 149) ng . L-1 in LPS group, P < 0.01. CCK-8 significantly inhibited the LPS-induced increase of TNF-alpha content in spleen. It decreased to (462 +/- 87) ng . L-1 in CCK - 8 + LPS group, P < 0.01. The expression of TNF-alpha mRNA 30 min and 2 h after treatment was stronger in LPS group, while it was lowered after CCK-8 pretreatment. The p38 MAPK expression increased significantly in LPS group (5.84 times of control) and CCK-8 increased the activation of p38 MAPK in ES rats (10.74 times of control). CONCLUSION: CCK-8 reverses the decrease of MAP in ES rats and has inhibitory effect on the gene and protein expression of TNF-alpha, in spleen, and p38 MAPK may be involved in its signal transduction mechanisms.