Hyaluronic acid and proliferation/cellular death amount in the female rats mammary gland after estroprogestative therapy

Aims To evaluate the concentration of hyaluronan acid and proliferation/cellular death in mammary gland of ovariectomized female rat after estroprogestative therapy. Materials and methods Forty ovariectomized female rats were divided into four groups with 10 animals/each: OG (vehicle); EG: (Estradiol, 7 days of treatment), PG (Progesterone acetate, 23 days of treatment), and EPG: (Estradiol, 7 days of treatment, and next Progesterone acetate, 23 days of treatment). Twenty-four hours after the last treatment, all animals were euthanized, the mammary gland removed, then, a fragment was immersed in acetone to quantifying of the hyaluronan acid biochemical method (ELISA-Like fluorometric assay), and a fragment fixed for 24 h in 10% formaldehyde in phosphate-buffered saline (PBS) processed for immunohistochemistry method for detection of the cell marker proliferation (Ki67) and cellular marker death by DNA fragmentation the TUNEL method. Results The estradiol-treatment alone (EG) or associated with progesterone (EPG) affected the concentration of hyaluronan acid, increased cell proliferation, and decreased cell death compared to OG and PG (p < .05) in the mammary tissue. Conclusions Our results suggest that the excessive reduction of HA in mammary tissue, as occurred with progesterone treatment, can lead to a breakdown of the extracellular matrix. These changes may be indicative of mammary pathology such as the development of tumor.

Automated summary

The estradiol treatment alone (EG) or associated with progesterone (EPG) affected the concentration of hyaluronan acid, increased cell proliferation, and decreased cell death in mammary tissue.