[Effect of nicotine on the secretion of TNF of human peripheral blood mononuclear cells in vitro].
OBJECTIVE
To observe the effect of nicotine on the secretion of TNF of human peripheral blood mononuclear cells (PBMC) in vitro, and explore the possible mechanism of the high level of TNF caused by smoking.


METHODS
Twenty-one non-smokers and 19 smokers were studied. The PBMCs isolated from each volunteer's blood sample were distributed to three groups, and cultured for 72 hours in supplemented RMPI 1640 alone or in supplemented RPMI 1640 containing 50 ng.ml-1 nicotine or 500 ng.ml-1 nicotine respectively. The level of TNF in supernate was quantified with the immuno-radioassay, and PBMC proliferation was observed.


RESULTS
The level of TNF spontaneously secreted by PBMCs in smokers was significantly higher than that in non-smokers (P < 0.05). When the concentrations of nicotine were 50 ng.ml-1 and 500 ng.ml-1, the level of TNF increased significantly in non-smokers (P < 0.05, P < 0.01). In smokers, the level of TNF significantly increased when the concentration of nicotine was 50 ng.ml-1; however, the level of TNF significantly decreased (P < 0.05), and the proliferation of PBMCs was inhibited when the concentration of nicotine was 500 ng.ml-1 (P < 0.05, P < 0.05). The level of TNF was positively correlated to the multiple of PBMC proliferation (r = 0.93, P < 0.05). The linear regression equation was Y = 2.913X - 2.955.


CONCLUSIONS
Nicotine can induce PBMCs to secrete more TNF, and the magnitude of the effect is strongly related to the dosage of nicotine, but a great dose of nicotine will inhibit the production of TNF.
Lei
Guang-hua
GH
Department of Orthopedics, Xiangya Hospital, Central South University, Changsha 410008, China.
Li
Kang-hua
KH
Zhou
Jiang-nan
JN
D000328:Adult; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009538:Nicotine / Q000494:pharmacology*; D012907:Smoking / Q000097:blood*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
D014409:Tumor Necrosis Factor-alpha; D009538:Nicotine