FIG. 6.
Lipocalin-2 deficiency prevents aging- and obesity-induced TNF-α expression, whereas lipocalin-2 treatment stimulates TNF-α expression in adipose tissues. A: Quantitative PCR analysis of TNF-α mRNA levels in the adipose tissues derived from different ages of mice fed with normal chow (left panel) or high-fat diet (right panel). *P < 0.05 vs. Lcn2-KO mice, n = 5. B: The protein levels of TNF-α were assayed in membrane and soluble fractions of adipose tissues using the commercial ELISA kit. *P < 0.05 vs. wild-type mice, n = 5. C: Quantitative PCR analysis of TNF-α (left panel) and 12-lipoxygenase (right panel) levels in epididymal fat pad collected from Lcn2-KO mice (six-week-old) treated with adenovirus overexpressing luciferase (rAd-luciferase) or lipocalin-2 (rAd-Lcn2). The latter group was injected with vehicle or CDC as described in research design and methods. Vehicle treatment did not cause any changes on TNF-α or 12-lipoxygenase expression (data not shown). The fold changes were calculated by comparing with rAd-luciferase–treated standard chow-fed wild-type mice. *P < 0.05 vs. rAd-luciferase mice fed with standard chow; #P < 0.05 vs. rAd-Lcn2 group, n = 5.