Introduction: Diabetes mellitus is associated with biochemical, physiological, and pathological changes. The purpose of this study was to investigate the histological changes in the liver of the newborn rats born to mothers with metabolic syndrome and diabetes mellitus before and after pregnancy.

Materials and Methods: This study was conducted on 32 rats (i.e., 2 males and 30 females). The rats were assigned into seven groups, including controls (n=2), diabetic group without exercise and metformin (n=5), diabetic group with exercise and without metformin (n=5), diabetic group with exercise and metformin (n=5), metabolic syndrome group without exercise and metformin (n=5), metabolic syndrome group with exercise and without metformin (n=5), and metabolic syndrome group with metformin and without exercise (n=5). After the addition of salt and fat to the diet of the rats with metabolic syndrome and induction of diabetes by streptozotocin in rats, they were sent for sampling. To this end, the rats were placed in a desiccator containing a cotton soaked with chloroform (Merck of Germany). After anesthesia, the rats were transferred and fixed to an appropriate board for sampling. The tissue was then isolated and placed in 10% formaldehyde solution that was replaced after 24 h. At this stage, the samples were prepared for histopathological examination.

Result: The diabetic groups showed tangible changes in the hepatocyte, central vein of the lobule, hepatic lobule, and sinusoidal space after the administration of metformin, compared to the control group. Furthermore, a reduction was observed in the hepatocyte and other factors. In the metabolic syndrome groups, changes in the central vein of the lobule, hepatocyte, sinusoidal space, and inflammation increased. These groups also showed a significant decrease in the changes of the sinusoidal space, hepatic lobule, and inflammation following the exercise therapy.