[Regeneration of the parathyroid glands following mechanical trauma]

During the interval of 3h-42 days regeneration of the parathyroid glands traumatized by means of forceps has been studied in 66 rats. The model presented reproduces the postoperative state of hypoparathyreosis occurring in the clinic. Ten intact and 30 pseudooperated animals serve as controls. The material is treated by means of histological, histochemical and morphometric methods (the stereological one including). The function of the gland is estimated according to total calcium content in blood serum. After 3-17th the parathyroid gland trauma produces some foci of parenchymal destruction. On the second day connective tissue begins developing in them. Epithelial regeneration occurs at the expense of an increased mitotic activity of the chief cells in the noninjured parts of the gland up to 0.9-1.5%, after 3-4 days hypertrophy of epitheliocytes, their nuclei and nucleoli, increasing number of nucleoli in the nucleus. After 5-10 days a limited outgrowth of the glandular parenchyma within large foci of the lesion is observed in some animals. Because of a rapid development of the connective tissue scars, however, at the place of the destroyed glandular parenchyma areas, there is no normalization of the organ's structure and function by the 42d day. A relative volume of stroma increases as much as 3-4 times as compared to the noninjured gland. The quantitative data dynamics analised demonstrate certain phasing in the regenerative processes: period of an alteration and an active macrophagal reaction (first 48 h after trauma), period of an active regeneration (the 2d - the 6th day), period of a temporary compensation (the 8th - the 13th day), period of a stable hyperfunction of the organ (the 16th - the 42d day).