Impact of Conjugated Linoleic Acid on Obesity and Its Association with Macrophage Recruitment: Experimental and Immunohistochemical Study.

Background: Conjugated linoleic acid (CLA) has been shown in humans and animals to have anti-adipose effects. The current study aims to assess the prophylactic and therapeutic impact of CLA and its effect on recruited macrophage type using immunohistochemistry against CD68 and CD 163.

Materials and methods: Forty adult male albino rats of local strain were included in the study and divided into control, CLA-supplemented, obese, CLA-prophylactic obese, and CLA-treated obese groups. Biopsies from visceral fat of the investigated groups were obtained and assessed for histopathological changes and immunohistochemical staining for CD68 and CD163.

Results: Obese group showed hypertrophied adipocytes and infiltration by inflammatory cells compared to other groups. The obese group showed a marked increase in the CD68 positivity compared with that in the control and CLA-supplemented groups. CLA-prophylactic and CLA-treated groups showed mild immune reaction with a significant decrease in CD68 positivity compared to the obese group. The obese group showed a significant decrease in the CD163 positivity compared with that in the control and CLA-supplemented groups.

Conclusions: Adipose tissue in obese is characterized by inflammation with more M1 than M2 macrophages. CLA could direct the recruited macrophages toward the anti-inflammatory subtype (M2) which encourages its beneficial effects in prophylaxis from obesity.