Bodart G, Farhat K, Renard-Charlet C, Becker G, Plenevaux A, Salvatori R, Geenen V, Martens H. The Severe Deficiency of the Somatotrope
GH-Releasing Hormone/Growth Hormone/Insulin-Like Growth Factor 1 Axis of
Ghrh-/- Mice Is Associated With an Important Splenic Atrophy and Relative B Lymphopenia.
Front Endocrinol (Lausanne) 2018;
9:296. [PMID:
29928261 PMCID:
PMC5997896 DOI:
10.3389/fendo.2018.00296]
[Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 05/17/2018] [Indexed: 11/13/2022] Open
Abstract
A debate is still open about the precise control exerted by the somatotrope GH-releasing hormone (GHRH)/growth hormone (GH)/insulin-like growth factor 1 axis on the immune system. The objective of this study was to directly address this question through the use of Ghrh-/- mice that exhibit a severe deficiency of their somatotrope axis. After control backcross studies and normalization for the reduced global weight of transgenic mice, no difference in weight and cellularity of the thymus was observed in Ghrh-/- mice when compared with C57BL/6 wild-type (WT) control mice. Similarly, no significant change was observed in frequency and number of thymic T cell subsets. In the periphery, Ghrh-/- mice exhibited an increase in T cell proportion associated with a higher frequency of sjTREC and naïve T cells. However, all Ghrh-/- mice displayed an absolute and relative splenic atrophy, in parallel with a decrease in B cell percentage. GH supplementation of transgenic mice for 6 weeks induced a significant increase in their global as well as absolute and relative splenic weight. Interestingly, the classical thymus involution following dexamethasone administration was shown to recover in WT mice more quickly than in mutant mice. Altogether, these data show that the severe somatotrope deficiency of Ghrh-/- mice essentially impacts the spleen and B compartment of the adaptive immune system, while it only marginally affects thymic function and T cell development.
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