Histochemical Study of Innervation and NADPH‐D Activity of the Thymus

Abstract

Acetylcholinesterase (ACHE)-positive nerve fibres in the thymus of the rat form perivascular plexuses as well as free ACHE-positive nerves, which do not follow the course of the vessels. A higher number of ACHE-positive nerves was observed in corticomedullary border and the medulla, a lower number in the cortex of the thymus lobuli. A gradual reduction of ACHE-positive intrathymus nerve formation was recorded and correlated with the increasing age of the rats. Nicotinamide adenine dinucleotide phosphate-diaphorase positive cells observed in the rat thymus were irregular with numerous projections and were located on the boundary of the cortex and medulla.

NADPH-d activity in rat thymus after the application of retinoid acid

“…25 Our results are in agreement with other authors, who also confirmed that NADPH-d positive cells are present in the rat thymus. 26–28 The observation of the thymus after the application of retinoid acid confirms the resemblance of NADPH-positive cells described by Gulati et al 27 In a further study, the same authors studied these cells at the electron-microscopic level. 29 …”

Betulinic acid‑induced expression of nicotinamide adenine dinucleotide phosphate‑diaphorase in the immune organs of mice: A possible role of nitric oxide in immunomodulation

“…Although NO is less active in cells from normal mice ( 43 ), a spleen cell subpopulation produces enough NO during an in vitro immune response to completely prevent multiplication of T cells ( 44 , 45 ). Similarly, previous studies have demonstrated that a wide range of potential immunomodulatory functions may be expected for NO in the thymus, including the following: Induction of tolerance, restriction of major histocompatibility complex, lymphocyte trafficking and regulation of thymic endocrine output ( 33 , 36 , 37 , 42 ). Furthermore, if there are effects or changes in the cells due to BetA treatment, it is assumed that NO may be produced to perform its regulatory roles in the cells of these immune organs.…”

“…Although NADPH-d expression was detected after 4 days, a significant increase in expression was observed after 8 days of BetA treatment, indicating the contribution of NADPH-d in spleen NO generation during the entire treatment period. Similarly, a steady increase in NADPH-d activity in the thymus beginning from day 4 may specify an interactive outcome of NO on the thymus vascular and medulla regions, which may be involved in immune modulation ( 33 , 36 – 37 ). Although the function of NO in the thymus and spleen has not been demonstrated, the findings of the current study indicate that there is an association between the immunological effects induced by BetA.…”

“…It has been demonstrated that the expression of NOS and production of NO are characteristic of cells involved in immune responses ( 33 , 36 , 42 ). Although NO is less active in cells from normal mice ( 43 ), a spleen cell subpopulation produces enough NO during an in vitro immune response to completely prevent multiplication of T cells ( 44 , 45 ).…”