engleski

Determination of collagen content and number of CD68 and CD163 positive cells in white adipose tissue of male rat offspring depending on maternal and postnatal diet

Introduction: Adipose tissue dynamically responds to increased or decreased caloric intake by adipocytes passing through hypertrophy and hyperplasia process and thus maintaining the energy homeostasis of the body. Processes of adipose tissue change are called adipose tissue remodelling and occur during obesity. They are characterized by infiltration of proinflammatory cytokines, enhanced angiogenesis and increased deposition of extracellular matrix proteins, and collagens form the largest group of extracellular matrix proteins which structure and density are strictly regulated. Another important step in adipose tissue remodelling is inflammation and macrophage infiltration into growing adipose tissue. Obese subject have an elevated percentage of macrophages and increased collagen build-up in adipose tissue. To conclude, inflammation and fibrosis are two biological processes that can explain the effects of obesity. Methods: Ten female Sprague Dawley rats were at 9 weeks of age randomly divided into two groups and fed either standard laboratory chow or food rich in saturated fatty acids during 6 weeks and then mated with genetically similar male rats. After birth and lactation, male rat offspring were divided into four subgroups depending on the diet they were fed until 22 weeks of age. After sacrifice, samples of white adipose tissue were taken from the subcutaneous, epididymal and perirenal white fat compartment. Histological staining of extracellular components was performed with Mallory's trichrome connective tissue stain, and histomorphometric analysis of digital images of histological tissue sections was conducted using the free online image analysis program Fiji. Immunohistochemical staining for CD68 and CD163 was also performed, and the number of CD68 and CD163 positive cells was counted per mm2 of adipose tissue. Results: The staining of extracellular components such as collagen showed a reduced collagen deposition in the control group in all fat pads, which was statistically significant compared to the groups of pups fed high-fat diet. The number of CD68 positive cells per mm2 of adipose tissue was the highest in groups where both mother and offspring were fed a high-fat diet, although there was no statistical significance among groups. When counting the number of CD163 positive cells per mm2, the highest number in subcutaneous and epididymal fat was found in the groups with changed diet, which was statistically significant compared with the groups with unchanged postnatal diet in epididymal adipose tissue compartment. Conclusion: Mother’s diet and changes in postnatal diet in offspring can induce morphological changes in adipose tissue and cause increased deposition of extracellular matrix proteins and changes in macrophage polarisation.

collagen ; obesity ; high-fat diet ; CD163

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