NIKNAFS B, TAKI T, REZAZADEH M, ALIMOHAMMADIAN M. MORPHOLOGICA L STUDY OF MOUSE (BALB/c) THYMUS A FTER HIGH A ND LOW DOSE DEXA METHA SONE TREATMENT. Med J Islam Repub Iran 1998; 12 (1) :65-69
URL:
http://mjiri.iums.ac.ir/article-1-1049-en.html
From the Department of Anatomy, Faculty of Medical Sciences, Tarbiat Modarres University, Tehran
Abstract: (4169 Views)
Dexamethasone induces thymic atrophy and thymocyte apoptosis. In the
present study histological and ultrastructural changes which occur in the thymus of
the mouse (BALB/c) following treatment with high (20 mg/kg) and low (8 mg/kg)
doses of dexamethasone were investigated. In low dose treated mice, apoptotic cells
were observed focally and localized mainly in thymic nurse cells (T.N.C.). A zone
of intact thymocytes was formed in the medulla of animals receiving 20 mg/kg of
dexamethasone as well as an increase in trans-endothelial vesicles and a decrease in
the size of the vesicles in the cortical capillaries. The enveloped thymocytes within
thymic nurse cells respond to dexamethasone through apoptosis, and these changes
were seen to be more severe in mice treated with high doses of dexamethasone. The
formation of apoptotic cells in the thymus caused by low dose dexamethasone
mimics the physiological process of cell death. Differential effects of low dose and
high dose dexamethasone may have pharmacological and immunological implications.