title: Exercise training attenuates adipose tissue fibrosis in diet-induced obese mice.
abstract: Tissue fibrosis, such as that which occurs in obesity, is associated with chronic inflammatory diseases. Although regular exercise reduces adipose tissue inflammation, the mechanisms regulating the effects of exercise on adipose tissue fibrosis are unclear. This study aimed to clarify whether exercise training attenuates adipose tissue fibrosis with consequent reduction of extracellular matrix including collagens. Male C57BL/6J (4-week old) mice were randomly assigned to four groups that received a normal diet (ND) plus sedentary (n=8), an ND plus exercise training (n=8), a high-fat diet (HFD) plus sedentary (n=12), and an HFD plus exercise training (n=12). Mice were fed the ND or HFD from 4 to 20 weeks of age. The exercise groups were trained on a motorized treadmill for 60 min/day, 5 times/week over the same period. Histological hepatic fibrosis detected by Sirius red and α-smooth muscle actin staining were attenuated in HFD exercise mice compared with HFD sedentary mice. mRNA levels of transforming growth factor-β and tissue inhibitors of metalloproteinase-1, major regulators of tissue fibrosis, were increased in HFD sedentary mice but were attenuated in HFD exercise mice. Similarly, adipose tissue from the HFD sedentary mice contained higher macrophages than adipose tissue from the ND mice, and this was also lowered by exercise training. These findings suggest that exercise training may be effective for attenuating adipose tissue inflammation in obesity.
authors.affiliation: Faculty of Sport Sciences, Waseda University, 2-579-15, Tokorozawa, Saitama 359-1192, Japan. Electronic address: kawanishinoriaki@akane.waseda.jp.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Kawanishi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Niihara
authors.forename: Tsubasa
authors.initials: T
authors.lastname: Mizokami
authors.forename: Hiromi
authors.initials: H
authors.lastname: Yano
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D000818:Animals; D059305:Diet, High-Fat / Q000009:adverse effects; D005080:Exercise Test; D005355:Fibrosis; D008103:Liver Cirrhosis / Q000628:therapy*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000209:etiology / Q000473:pathology* / Q000628:therapy*; D010805:Physical Conditioning, Animal; D057185:Sedentary Behavior
keywords: Collagen; High-fat diet; Macrophage; TGF-β; TIMP-1; tissue inhibitor of metalloproteinase-1; transforming growth factor-beta