Ramirez-Otarola Natalia, Espinoza Janyra, Kalergis Alexis M, Sabat Pablo
Department of Ecological Sciences, Science Faculty, Universidad de Chile, Santiago, Chile.
Department of Ecology, Center of Applied Ecology & Sustainability, Biological Sciences Faculty, Pontificia Universidad Católica de Chile, Santiago, Chile.
Integr Zool. 2019 May;14(3):235-247. doi: 10.1111/1749-4877.12329.
During vertebrate development, the immune function is inefficient and is mainly controlled by innate defense. While there have been detailed studies of various aspects of innate immune function, the effects of this function in the growth of vertebrates is still not well known. Similarly, there is little information regarding how early endotoxin exposure would affect juvenile phenotypes, specifically in a non-model mammal like a precocial rodent. We evaluated the response to an antigen and its cost in offspring of the rodent Octodon degus. We inoculated pups at 4 different ages (8, 15, 22 and 30 days after birth) with an antigen to determine the ontogeny and costs of the response to an endotoxin. We assessed changes in body mass, body temperature, sickness behavior and the levels of a key mediator of the inflammatory response, the cytokine interleukin-1β. We also determined the effects of early endotoxin exposure on the resting metabolic rate of juvenile animals (i.e. 90 days after birth). The cytokine levels, body mass and body temperature were unaffected by time of inoculation and treatment. However, pups subjected to inoculation at 22 days after birth with the antigen showed reduced locomotion. Juvenile resting metabolic rate was not affected by early endotoxin exposure. These results suggest that the magnitude of O. degus responses would not change with age. We discuss whether the lack of effect of the response on body mass or body condition is caused by environmental variables or by the precocial characteristics of O. degus.
在脊椎动物发育过程中，免疫功能效率低下，主要由先天防御控制。虽然对先天免疫功能的各个方面已有详细研究，但该功能在脊椎动物生长中的作用仍不太清楚。同样，关于早期接触内毒素如何影响幼年表型，特别是在像早熟啮齿动物这样的非模式哺乳动物中，相关信息也很少。我们评估了啮齿动物八齿鼠后代对抗抗原的反应及其代价。我们在4个不同年龄（出生后8、15、22和30天）给幼崽接种抗原，以确定对内毒素反应的个体发生情况及其代价。我们评估了体重、体温、疾病行为以及炎症反应关键介质细胞因子白细胞介素-1β水平的变化。我们还确定了早期接触内毒素对幼年动物静息代谢率（即出生后90天）的影响。细胞因子水平、体重和体温不受接种时间和处理的影响。然而，出生后22天接种抗原的幼崽运动能力下降。早期接触内毒素未影响幼年动物的静息代谢率。这些结果表明，八齿鼠的反应强度不会随年龄变化。我们讨论了反应对体重或身体状况缺乏影响是由环境变量还是八齿鼠的早熟特性引起的。
