Introduction:
The mechanisms of metabolic syndrome (MS) is one of the urgent issues in medicine. Regional distribution of the adipose tissue should be diagnosed at clinical examination, as the morphometric parameters of the cells of the active adipose tissue components may indicate the metabolic state.

Aim:
The aim of the study was to evaluate the differences in morphological and histological parameters of the adipose tissue associated with the development of MS in animals of different ages and gender.

Material and methods:
An experimental study was carried out on 144 WAG/G Sto white rats, divided into three study groups. Group 1 included young immature rats, 3 months old; group 2 consisted of 48 sexually mature rats, aged 5–6 months; group 3 consisted of 48 old rats, 18 months old. Each group was divided into 2 subgroups, control and experimental, and was additionally divided according to gender.

Results and discussion:
The body mass indices and specific weights of mesenteric, epididymal, retroperitoneal and subcutaneous adipose tissue were determined in rats, as well as morphological characteristics of adipocytes of the adipose tissue. It was shown that histological and morphological changes in the adipose tissue of the animals were age- and gender-dependent, and that obesity is associated with chronic inflammation of the adipose tissue.

Conclusions:
The results of the study can be used for further determination of possible age and gender differences in the adipose tissue involvement in the development of chronic inflammation, as well as monitoring and correction of adipose tissue dysfunction in MS.