[Late effects of experimental ablation of the pineal gland on ultrastructural morphometric changes in thymic epithelial cells].

The late effect of surgical ablation of pineal gland on the morphometric changes in epithelial cells of rat thymus were investigated. The aim of this study is to determine a possible existence of sex-different changes in composition of the epithelial cell component unit long after pinealecotmy what could be important for the subtle understanding of mutual correlation between pincal body and thymus. This article presents results of stereological ultrastructure parameters of thymuscortical and medullar epithelial cells of male and female rats two month after pinealectomy. The experimental animals were divide into two groups: an experimental one (pinealectomized) and the control group (shampinealectomized). Pinealectomized animals were submitted to surgical ablation of pineal gland while the control were undertaken the same surgical treatment but without removal of the pineal gland. Animals were sacrificed 60 th days following the surgery treatment. Parasagital pieces of thymus tissue were fixed by means of immersion in glutaraldehyde and prepared for transmission electron microscopy. Using Weibls multipurpose test system and multilevel sampling technique on electron micrographs the volume and surface density of nucleus (Vu, Sv) and cytoplasm of cortical and medullar thymus epithelial cells were calculated. At the different magnification level were established the volume and surface density of mitochondria (Vvm, Svm) endoplasmic reticulum (Vvr, Svr), vacoule(Vuv) as well as numerical density of mitochondria (Nvm). Our analysis has conformed statistically significant increase in Vv of reticulum and vacuole in both sex of pinealectomized rats. Sv of plasmalema, reticulum and mitochondrial membrane are markedly increased in thymus medullar epithelial cells of pienalectomized rats. Vv of mitochondria is significantly increased in cortical epithelial cells of pienalectomized animals. Results allow us to confirm that mutual correlation between pineal gland and thymus exists but present findings seem to support the concept of sex independent inhibitory action of pineal gland on thymus cortical and medullar epithelial cells.