ラット耳下腺の加齢と性ホルモンの影響

抄録

We evaluated the effects of estrogen on the parotid gland. Female rats were divided into 3 groups. Group 1 (aging group): Thirty-three rats were used, and the parotid gland was resected at the age of 19, 28 and 41 weeks (n=3 for each experimental group), 49, 55, 58 and 61 weeks (n=6 for each experimental group) to provide premenopause data. Thirty-six rats were used to supply postmenopause data. Menopause was confirmed by observation of vaginal smears, and the parotid gland was resected at 3, 6, 9, 12, 18 and 24 weeks (n=6) after menopause. Group 2 (ovariectomy group): Ovariectomy was performed at the age of 15 weeks in 36 rats, and the parotid gland was resected at the age of 18, 21, 25, 27, 33 and 39 weeks (n=6). Group 3 (ovariectomy+estrogen administration group): Ovariectomy was performed at the age of 15 weeks in 12 rats. Subsequently, an ALZET mini osmotic pump containing 17 β-estradiol dissolved in propylene glycol was subcutaneously implanted into the rat dorsum. The parotid gland was resected at the age of 27 and 39 weeks (n=6). The resected right parotid gland specimens were fixed with formalin, embedded in paraffin, and preparations were made in the plane showing a maximum area. After hematoxylin-eosin staining, images were incorporated into a computer, and the percentage of the fatty tissue area to the entire visual field of the tissue was calculated using NIH image.
The percentage of fatty tissue increased with the course postmenopause in groups 1 and 2. In group 3, the percentage decreased. These results suggest that estrogen deficiency is involved in fatty degeneration in the parotid gland. Though the indirect association between salivation and ovarian hormones has been suggested, our results showed that the hormone involved in fatty degeneration in the parotid gland is estrogen.