Effect of acute heat stress on calcium concentration, proliferation, cell cycle, and interleukin-2 production in splenic lymphocytes from broiler chickens.
In the present study, we investigated the effects of acute heat stress on the concentration of free Ca2+ ([Ca2+]i) and markers of cellular immunity in splenic lymphocytes from broiler chickens. Eighty 6-wk-old male broilers were randomly allocated to 2 treatments and exposed to 25 and 35°C (RH, 50±5%) for 3 h. We observed that 3 h of heat exposure (35±1°C, 50±5% RH) increased the body temperature and respiratory rate of broiler chickens significantly, but plasma levels of corticosterone were not changed. Examination of [Ca2+]i and the proliferation of splenic lymphocytes isolated from heat-stressed broiler chickens, using fura-2-acetoxymethyl ester and Cell Counting Kit-8, respectively, showed that acute heat stress caused a significant increase in [Ca2+]i and enhanced concanavalin A-stimulated but not lipopolysaccharide-stimulated lymphocyte proliferation significantly. Flow cytometric analysis of the cell cycle and T-lymphocyte subsets (CD4+ and CD8+) indicated that heat stress promoted the transition of lymphocytes from gap phase 1 to synthesis phase and increased the ratio of CD4+ to CD8+ of T lymphocytes. In addition, acute heat stress enhanced the secretion of interleukin-2 by splenic lymphocytes significantly. These results suggest that the effect of acute heat stress to increase the [Ca2+]i in lymphocytes may be an early event that enhances Con A-stimulated T-cell proliferation and interleukin-2 secretion and promotes the transition of T cells from gap phase 1 to synthesis phase.
Han
A Y
AY
State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China.
Zhang
M H
MH
Zuo
X L
XL
Zheng
S S
SS
Zhao
C F
CF
Feng
J H
JH
Cheng
C
C
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002453:Cell Cycle; D049109:Cell Proliferation; D006358:Hot Temperature; D007376:Interleukin-2 / Q000235:genetics / Q000378:metabolism*; D016131:Lymphocyte Subsets / Q000145:classification / Q000166:cytology / Q000378:metabolism*; D008297:Male; D013154:Spleen / Q000166:cytology*; D013312:Stress, Physiological
D007376:Interleukin-2; D002118:Calcium