Reduced Exercise Endurance in Interleukin-6-Deficient Mice

Kiyama

et al. 2012

Tohoku J. Exp. Med.

The cytokine interleukin-6 (IL-6) is released from working skeletal muscles and reportedly plays key roles in their glucose homeostasis. However, it is unclear whether IL-6 plays such roles in the masseter muscle (MM), which is important in normal and pathological chewing behaviors, such as bruxism and/or prolonged clenching. When restrained (R+) in a narrow cylinder blocked at the front end with a thin plastic strip, a mouse gnaws away (G+) the strip to escape. The absolute weight of plastic gnawed away serves as an index of MM activity. Using this model, we examined the roles of IL-6 in MM with the following results. R+G+ increased the expression levels of IL-6 and glucose transporter 4 (Glut4) mRNAs in MM and the serum level of IL-6 protein. IL-6-deficient mice exhibited about 60% less gnawing activity than wild-type mice at 3-4 h after the start of R+G+, slower recovery of glycogen levels (indicating poorer glucose supply) in MM after R+G+, and no significant change in Glut4 mRNA in MM upon R+G+. During an R+G+ test conducted after "training" (repeated R+G+ sessions), wild-type mice exhibited greater gnawing activity than untrained controls, but no increase in IL-6 mRNA in MM. IL-6 mRNA increased in MM when hard food was eaten by mice raised on soft food for 3 weeks from weaning, but not in those raised on (accustomed to) hard food. Thus, IL-6 may maintain glucose homeostasis in MM in support of unusually strenuous activity, but not of accustomed activity levels.

Section: Discussionsupporting

confidence: 93%

mentioning

confidence: 99%

Interleukin-6 Maintains Glucose Homeostasis to Support Strenuous Masseter Muscle Activity in Mice

Kiyama

et al. 2012

Tohoku J. Exp. Med.

“…[27][28][29] Moreover, endogenous IL-6 seems to influence energy expenditure during exercise. 30 Interestingly, the data of recent studies indicate that the -174 C allele is associated with decreased energy expenditure 31 and slightly decreased body temperature. 14 Taken together, these results indicate that the À174 C allele of the IL-6 promoter decreases IL-6 production, which in turn results in decreased energy expenditure and accumulation of body fat.…”

Section: Discussionmentioning

confidence: 99%

A common polymorphism in the interleukin-6 gene promoter is associated with overweight

et al. 2004

OBJECTIVE:Human body fat mass is to a large extent genetically determined, but little is known about the susceptibility genes for common obesity. Interleukin-6 (IL-6) suppresses body fat mass in rodents, and IL-6 treatment increases energy expenditure in both rodents and humans. The À174 G/C single-nucleotide polymorphism (SNP) in the IL-6 gene promoter is common in many populations, and À174 C-containing promoters have been found to be weaker enhancers of transcription. Moreover, a SNP at position À572 in the IL-6 promoter has recently been reported to affect transcription. The objective was to investigate the association between the IL-6 gene promoter SNPs and obesity. DESIGN: Trans-sectional association study of IL-6 gene promoter SNPs and indices of obesity. SUBJECTS: Two study populations, the larger one consisting of hypertensive individuals (mean age 57 y, 73% males, n ¼ 485) and the other consisting of 20 y younger nonobese healthy females (n ¼ 74). MEASUREMENTS: Genotyping for the À174 IL-6 G/C and the À572 G/C SNPs, body mass index (BMI), serum leptin levels, serum IL-6 levels, C-reactive protein, fasting blood glucose and various blood lipids. RESULTS: The common À174 C allele (f C ¼ 0.46), but not any À572 allele, was associated with higher BMI and higher serum leptin levels in both study populations. In the larger population, there were significant odds ratios for the association of CC (2.13) and GC (1.76) genotypes with overweight (BMI425 kg/m 2 ). Moreover, as the C allele was common, it accounted for a significant population-attributable risk of overweight (12%; CI 2-21%), although its average effect was modest in this sample. CONCLUSION: Genetically determined individual differences in production of IL-6 may be relevant for the regulation of body fat mass.

“…He postulated that this effect might be mediated by IL-6. Faldt et al 21 suggested that IL-6 exerts its effect by stimulating energy expenditure and reducing body fat mass. Further, IL-6 deficient mice had reduced endurance and energy expenditure during exercise.…”

Section: Il-6 and Tnf- Alterations With Exercise In Animal Modelsmentioning

confidence: 99%

Exercise and the cytokines-interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α): A review

Vijayaraghava

Doreswamy

2017

Ann Med Physiol.

Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were one of the first few cytokines to be discovered. The normative data for levels of cytokines IL-6 and TNF-α in particular and all other cytokines in general have not yet been established well. The normal levels for each of the cytokines vary from one race to another. Therefore, all studies need to be done in cases and controls belonging to the same race or same populations. The kits for cytokine assays are expensive and running the assays is laborious and time consuming. It is recommended that the serum/plasma samples are run in duplicates and triplicates to avoid error. Immunology and the field of cytokines is an area which has many domains unexplored. As yet, it is not clearly understood by what mechanisms and pathways each of the cytokines alter the levels of other cytokines. Exercise or physical activity is an intervention which can be administered easily and levels of cytokines measured before and after intervention in same individuals taking all the above mentioned factors into consideration. Hence it is imperative that we look into studies on exercise and cytokines to do further research in the field of cytokines.