[Impact of chronic restraint stress on splenocyte immunity and growth of mouse forestomach carcinoma xenografts in Kunming mice].
OBJECTIVE
Recent study found psychosocial factors play some important roles in carcinogenesis and development of malignant tumors, but its mechanisms remain unclear. This study was to investigate the impact of chronic restraint stress on splenocyte immunity and growth of mouse forestomach carcinoma (MFC) xenografts in Kunming mice, and provide evidences for exploring the mechanisms of psychosocial factors function on malignant tumors.


METHODS
A total of 60 Kunming mice were randomized into normal control group, restraint stress group, tumor-bearing group and tumor plus restraint stress group; each group contained 15 mice. Chronic restraint stress models were established in restraint stress group and tumor plus restraint stress group; MFC xenograft models were established in tumor-bearing group and tumor plus restraint stress group 4 weeks later. Mice were killed 10 days after inoculation of MFC cells. The weight of MFC xenografts were measured. The proliferation and cytotoxicity of splenocytes were detected by MTT assay. The level of interleukin-2 (IL-2) in splenocyte culture supernants was detected by enzyme-linked immunoabsorbent assay (ELISA).


RESULTS
The weight of MFC xenografts was (1.39+/-0.39) g in tumor-bearing group and (2.10+/-0.52) g in tumor plus restraint stress group; MFC xenografts grew faster in tumor plus restraint stress group than in tumor-bearing group (P<0.01), with a tumor growth rate of 51.08%. In normal control group, restraint stress group, tumor-bearing group, and tumor plus restraint stress group, the stimulus indexes (SI) of T lymphocytes were 1.77+/-0.22, 1.70+/-0.17, 1.69+/-0.18, and 1.22+/-0.15, respectively; the SI of B lymphocytes were 1.73+/-0.14, 1.65+/-0.17, 1.64+/-0.21, and 1.33+/-0.11, respectively; the inhibition rate of MFC cell proliferation were (23.01+/-4.76)%, (19.47+/-3.70)%, (16.81+/-3.68)%, and (7.14+/-5.00)%, respectively, when the effector/target ratio was 5:1 and (33.03+/-3.91)%, (28.34+/-4.58)%, (24.94+/-2.97)%, and (13.49+/-7.94)%, respectively, when the effector/target ratio was 10:1; the levels of IL-2 in splenocyte culture supernatants were (260.03+/-14.96) pg/mL, (239.78+/-10.93) pg/mL, (238.11+/-13.50) pg/mL, and (186.34+/-10.42) pg/mL, respectively. Both chronic restraint stress and MFC xenografts impaired the proliferation, cytotoxicity, and IL-2 secretion of splenocytes; the two factors showed interactive effect (P<0.01), but the effect of chronic restraint stress was much more obvious.


CONCLUSIONS
Chronic restraint stress may impair the immune function and promote the growth of MFC xenografts in mice.
Li
Jian
J
Department of Gastrointestinal Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, People's Republic of China. jamle1981@sina.com
Hu
Song
S
Zhang
Cai-Quan
CQ
Yang
Hai-Ping
HP
Ni
Chun
C
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D007376:Interleukin-2 / Q000378:metabolism; D008297:Male; D051379:Mice; D009368:Neoplasm Transplantation; D011897:Random Allocation; D012149:Restraint, Physical; D013154:Spleen / Q000166:cytology* / Q000378:metabolism; D013274:Stomach Neoplasms / Q000473:pathology*; D013312:Stress, Physiological; D013601:T-Lymphocytes / Q000276:immunology*; D047368:Tumor Burden
D007376:Interleukin-2