Celebration of Scholarship and Creative Activity 2021
Excess visceral adipose (i.e., fat), a key component of obesity, is known to trigger the release of proinflammatory cytokines that are implicated in the development of a low-grade chronic inflammation in overweight and obese people. To understand how weight gain or loss can impact the levels of adipose inflammation, we collected tissues from ground squirrels at different stages of their active and hibernating periods. These animals gain large amounts of fat during their active (summer) season and then live off these fat reserves while they hibernate. Thus, they experience repeated cycles of weight gain (summer) and loss (hibernating). We used ELISA to quantify two proinflammatory and one anti-inflammatory cytokine in the visceral adipose of these animals. We found that levels of the proinflammatory cytokine tumor necrosis factor (TNF)-α increased late in the active season and stayed elevated in early hibernators, finally dropping after 4 months of hibernation. Another proinflammatory cytokine, interleukin (IL)-6 was elevated in early summer and hibernating stages compared to later in each season. Levels of the anti-inflammatory cytokine interleukin (IL)-10 decreased significantly in the hibernating season compared to the summer season. Thus, we conclude that loss of adipose mass through metabolism can be an effective tool to reverse some obesity-induced body inflammation.