Thomas Jessica R, Woodley Sarah K
Department of Biological Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, USA.
Department of Biological Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, USA.
Gen Comp Endocrinol. 2017 Jun 1;247:8-15. doi: 10.1016/j.ygcen.2017.03.014. Epub 2017 Mar 24.
In vertebrates, a bidirectional relationship exists between the immune system and the hypothalamic-pituitary-gonadal axis. In addition, sexual dimorphism in immunity has been documented in many vertebrates as well as some invertebrates, and males are generally less immunocompetent than their female counterparts. A possible explanation for this is described by the immunocompetence handicap hypothesis (ICHH), which proposes that elevated testosterone (T) levels direct resources towards the promotion of secondary sexual characteristics at a cost to immune function. To further test the ICHH, we examined the effects of T on cutaneous wound healing, an integrative measure of immunity, using male Allegheny Mountain dusky salamanders; a species that has sexually dimorphic courtship glands and testosterone-dependent mating behavior. We did this via two methods: surgical manipulation and transdermal delivery of T. In both experiments, elevated plasma T did not delay wound healing. Interestingly, intact animals healed more slowly than animals that had undergone prior invasive surgery, suggesting that the prior surgery had an immune-priming effect that enhanced healing of a second wound.
在脊椎动物中，免疫系统与下丘脑 - 垂体 - 性腺轴之间存在双向关系。此外，许多脊椎动物以及一些无脊椎动物中都记录了免疫方面的性别二态性，并且雄性通常比雌性的免疫能力弱。免疫能力缺陷假说（ICHH）对此给出了一种可能的解释，该假说提出，睾酮（T）水平升高会将资源导向促进第二性征的发育，而这是以免疫功能为代价的。为了进一步检验ICHH，我们使用雄性阿勒格尼山暗色蝾螈研究了T对皮肤伤口愈合（一种综合性免疫指标）的影响；该物种具有性别二态性的求偶腺和依赖睾酮的交配行为。我们通过两种方法进行研究：手术操作和T的透皮给药。在两个实验中，血浆T水平升高均未延迟伤口愈合。有趣的是，完整未手术的动物比之前接受过侵入性手术的动物愈合得更慢，这表明先前的手术具有免疫启动作用，可增强第二个伤口的愈合。
