Effects of prophylactic administration of glutamine on CD4 ⁺ T cell polarisation and kidney injury in mice with polymicrobial sepsis

The present study investigated the effects of glutamine (GLN) pretreatment on CD4 ⁺ T cell polarisation and remote kidney injury in mice with gut-derived polymicrobial sepsis. Mice were randomly assigned to three groups: normal control fed with American Institute of Nutrition (AIN)-93G diet and two sepsis groups provided with either AIN-93G-based diet or identical components, except part of casein was replaced by GLN. Mice were given their respective diets for 2 weeks. Then, mice in the sepsis groups were performed with caecal ligation and puncture and were killed 72 h after the surgery. Blood, spleens and kidneys were collected for further examination. The results showed that sepsis resulted in decreased circulating and splenic total T lymphocyte and CD4 ⁺ T cell percentages, whereas IL-4-, and forkhead box p3 (Foxp3)-expressing CD4 ⁺ T cells percentages were up-regulated. Compared with the sepsis control group, pretreatment with GLN maintained blood T and CD4 ⁺ T cells and reduced percentages of IL-4- and Foxp3-expressing CD4 ⁺ T cells. Also, a more pronounced activation and increased anti-apoptotic Bcl-2 gene expression of splenic CD4 ⁺ T cells were observed. Concomitant with the decreased plasma IL-6, keratinocyte-derived chemokine (KC) levels, the gene expression of KC, macrophage inflammatory protein-2 and renal injury biomarker kidney injury molecule-1 (Kim-1) were down-regulated when GLN was administered. These findings suggest that antecedent of GLN administration elicit a more balanced blood T helper cell polarisation, sustained T cell populations, prevented splenic CD4 ⁺ T cell apoptosis and attenuated kidney injury at late phase of polymicrobial sepsis. GLN may have benefits in subjects at risk of abdominal infection.