title: Effects of hypothalamus destruction on the level of plasma corticosterone after blast injury and its relation to interleukin-6 in rats.
abstract: Hypothalamus-pituitary-adrenal (HPA) axis is involved in the modulation of the innate immune response. The purpose of this study was to evaluate the dynamic relationship between plasma corticosterone and interleukin-6 in the hypothalamus-destroyed rats after blast injury. A total of 105 Sprague-Dawley rats were divided randomly into normal control (normal), sham operated (sham), blast injury plus sham operated (blast injury) and blast injury plus hypothalamus destruction groups. Symmetric electrolytic bilateral destruction of the hypothalamus was performed for the deeply anesthetic rats under sterile conditions. Seven days after the destruction of the hypothalamus, the animals were succumbed to moderate blast injury using a BST-I bioimpact machine. Plasma corticosterone and IL-6 levels were determined by radioimmunoassay and enzyme-linked immunosorbent assay, respectively. After blast injury, the corticosterone level in the hypothalamus-destroyed rats was significantly lower than that in the rats without destruction of hypothalamus at 3h (P<0.01) or from 5 to 8h (P<0.05). Reduction of corticosterone may be intrinsically correlated with the severe tissue injury and increased mortality (4/15 vs. 0/15, P<0.05). Circulating IL-6 level was markedly elevated in response to blast injury and hypothalamus destruction further increased IL-6 secretion (P<0.05). We concluded that elevation of pro-inflammatory IL-6 secretion might compensate the impaired HPA axis function after the trauma occurred in the hypothalamus-destroyed rats. These results also suggested that release of hypothalamus hormones is necessary to maintain certain magnitude of innate immunity after trauma.
authors.affiliation: State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Changjiang Zhilu, Chongqing, PR China.
authors.forename: Ce
authors.initials: C
authors.lastname: Yang
authors.forename: Jie
authors.initials: J
authors.lastname: Gao
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Wang
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.forename: Min-Hui
authors.initials: MH
authors.lastname: Xu
authors.forename: Zheng-Guo
authors.initials: ZG
authors.lastname: Wang
authors.forename: Jian-Xin
authors.initials: JX
authors.lastname: Jiang
mesh_terms: D000818:Animals; D001753:Blast Injuries / Q000097:blood*; D003345:Corticosterone / Q000097:blood*; D003346:Corticotropin-Releasing Hormone / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D007030:Hypothalamo-Hypophyseal System; D007031:Hypothalamus / Q000473:pathology*; D015850:Interleukin-6 / Q000097:blood*; D008168:Lung / Q000473:pathology; D023421:Models, Animal; D011863:Radioimmunoassay / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D015850:Interleukin-6; D003346:Corticotropin-Releasing Hormone; D003345:Corticosterone