Physiological interactions between the hypothalamic-pituitary-gonadal axis and spleen in rams actively immunized against GnRH.
Hypothalamic-pituitary-gonadal (HPG) axis is strongly implicated in the regulation of immune system. The objective was to determine the effects of immunocastration on splenic reproduction- and immunity-related gene expressions, and serum cytokine profiles in rams. Forty rams were randomly allocated into three groups: control (n=14); surgically castrated (n=13); or immunized (n=13) against 100μg D-Lys6-GnRH-tandem-dimer peptide conjugated to ovalbumin in Specol adjuvant at 6months of age (with a booster 2months later). Blood samples (for hormone and immune cytokine profiles) were collected at 1-month intervals until rams were slaughtered (10months). Compared to intact controls, anti-GnRH immunization reduced (P<0.05) serum concentrations of LH, FSH, and testosterone. Reduced testosterone abrogated its inhibitor feedback effect on the synthesis of GnRH in spleen, as evidenced by increased (P<0.05) protein content and mRNA expressions of GnRH, and simultaneously decreased (P<0.05) mRNA expressions of androgen receptor in spleen. In parallel with the increased GnRH production in spleen, the mRNA expressions of interleukin (IL)-2, IL-4, IL-6 and tumor necrosis factor alpha (TNF-α) as well as lymphocyte marker CD4, CD8 and CD19 molecules were increased (P<0.05) in spleen. Consistently, serum concentrations of IL-2, IL-4, IL-6, TNF-α were increased (P<0.05) in rams following immunization. Similarly, deprivation of testosterone by surgical castration also increased (P<0.05) GnRH and thus immune cytokine expressions in spleen. Collectively, our data suggested that immunocastration increased GnRH production in spleen by abrogating the inhibitory feedback effects from testosterone, consequently improving the immune markers of spleen and serum immune cytokines in rams.
Isotope Research Lab, Sichuan Agricultural University, Ya'an 625014, People's Republic of China.
Xingfa
X
Han
Isotope Research Lab, Sichuan Agricultural University, Ya'an 625014, People's Republic of China.
Xiaohua
X
Ren
College of Animal Science, Sichuan Agricultural University, Chengdu Campus, Chengdu, Sichuan 611130, People's Republic of China.
Yu
Y
Zeng
Isotope Research Lab, Sichuan Agricultural University, Ya'an 625014, People's Republic of China.
Yuqin
Y
Zhou
Institute of Animal Science, Tibet Academy of Agricultural and Animal Husbandry Science, Lhasa 850009, People's Republic of China.
TianZeng
T
Song
Isotope Research Lab, Sichuan Agricultural University, Ya'an 625014, People's Republic of China.
Xiaohan
X
Cao
Isotope Research Lab, Sichuan Agricultural University, Ya'an 625014, People's Republic of China.
Xiaogang
X
Du
Isotope Research Lab, Sichuan Agricultural University, Ya'an 625014, People's Republic of China.
Fengyan
F
Meng
Isotope Research Lab, Sichuan Agricultural University, Ya'an 625014, People's Republic of China.
Yao
Y
Tan
Isotope Research Lab, Sichuan Agricultural University, Ya'an 625014, People's Republic of China.
Yacheng
Y
Liu
Institute of Animal Science, Tibet Academy of Agricultural and Animal Husbandry Science, Lhasa 850009, People's Republic of China.
Jing
J
Feng
Key Laboratory of Farm Animal Genetic Resources and Germplasm Innovation of Ministry of Agriculture, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, People's Republic of China.
Mingxing
M
Chu
Isotope Research Lab, Sichuan Agricultural University, Ya'an 625014, People's Republic of China. Electronic address: xyzeng1966@163.com.
Xianyin
X
Zeng
D000818:Animals; D002369:Castration; D002417:Cattle; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D025461:Feedback, Physiological; D007987:Gonadotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism*; D006066:Gonads / Q000502:physiology*; D007030:Hypothalamo-Hypophyseal System; D007031:Hypothalamus / Q000502:physiology*; D007107:Immune System; D007114:Immunization; D008297:Male; D010913:Pituitary-Adrenal System; D011944:Receptors, Androgen / Q000235:genetics / Q000378:metabolism; D012098:Reproduction; D012756:Sheep; D013154:Spleen / Q000502:physiology*; D013739:Testosterone / Q000378:metabolism*
D016207:Cytokines; D011944:Receptors, Androgen; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone
GnRH; Immune cytokines; Immunocastration; Ram; Reproductive axis; Spleen