[Reaction of thymic mononuclear phagocytes in rats 2 months after pinealectomy, ultrastructural-morphometric analysis of interdigitating cells].

The effects of pinealectomy on the dynamics of morphometric changes in interdigitating cells(IDC) of rat thymus were investigated. The experimental animals were divided into two groups: an experimental one and the control group. Animals from the first group were subjected to pinealectomy while the second group were treated in the same manner, but without the removal of the pineal gland. All the animals were sacrificed 60. days following the surgery. The thymus tissue were fixed by means of immersion and prepared for transmission electron microscopy. Using Weibl's multipurpose test system and multilavel sampling technique on electron micrographs, the nuclear volume density(Vvn) and cytoplasmic volume density(Vvc) were calculated. At the different magnification level established the surface density(Sv) of nucleoid and cell membranes as wel as surface density of rough endoplasmic reticulum and mitochondrial membranes (Svm) and their volume density. Our analysis has confirmed statistically significant increase in Vv of the nucleus of pinealectomized rats. The average volumen of IDC has been also increased after pinealectomy as well as Vv, Nv and Sv of the mitochondria. The present findings seem to support the concept of inhibitory action of pineal gland on thymus IDC.