Effects of Removal and Stimulation of Thymus on Tissue Histamine and Mast Cell Contents in Rats

Abstract

In the recent past, evidence has accumulated that there is an interesting but obscure relationship between genesis of mast cells and functions of thymus (1). In the present work, the effects of removal and direct antigenic stimulation of thymus on tissue histamine and mast cell contents in various tissues were studied on albino rats. In view of the existence of blood-thymus barrier as postulated by Nossal and Mitchell (2), injections of antigen were given directly into the substance of the gland. MATERIALS AND METHODSHealthy albino rats of both sexes weighing between 120 and 150 g were used. The method of Segaloff (3) was followed for thymectomy and sham thymectomy. For thymic stimulation, injections of I , egg white in normal saline were made into the substance of thymus modifying the method of Radwon and West (4). Tissues were fixed with 10 jo aqueous formalin, processed in alcohol, embedded in paraffin and sections 5,n thick were taken for all abdominal organs and dorsal skin and 71z thick for abdominal skin and mesen tery. Tissue mast cells were stained with toluidine blue as adopted by Gupta and Skeleton (5). Tissue histamine was extracted with 10°0 trichloracetic acid as adopted by Parrat and West: (6) and assayed on terminal guinea-pig ileum. All experimental animals were sac rificed at regular intervals and the effects were observed for a period of 30 days in cases of thymectomy and for 6 weeks in cases of antigenic stimulation. Observations of tissue histamine and mast cell contents were made on dorsal and abdominal skins, liver, spleen, mesentery and kidney with mean values of four groups being recorded.

A comparative study of the spatial distribution of mast cells and microvessels in the foetal, adult human thymus and thymoma

“…In normal thymus of humans and other animal species, MCs are localized in the capsule and along the connective tissue septa within the gland (Wight 1970;Frazier 1973;Kendall & Warley 1986). The presence of MCs precursors in thymus was first reported by Ginsburg and Sachs (1963) and further studies supported the possible involvement of MCs in thymus organogenesis ) and the influence of removal or stimulation of thymus on the number of tissue MCs distant from the thymic lymphoid tissue (Rao 1972).…”

“…The presence of MCs precursors in thymus was first reported by Ginsburg and Sachs (1963) and further studies supported the possible involvement of MCs in thymus organogenesis (Crivellato et al. 2005) and the influence of removal or stimulation of thymus on the number of tissue MCs distant from the thymic lymphoid tissue (Rao 1972).…”