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

Abstract

The aim of this work was to determine the localization of nicotinamide-adenine dinucleotide phosphate-diaphorase (NADPH-d) activity as the marker for synthesis of nitric oxide synthase (NOS) in the rat thymus after the application of retinoid acid (RA) on 1st, 7th, 14th and 21st days of gestation. The given results can build the basis for understanding of the role of NOS in rat thymus. NADPH-d positive cells were represented with dark-blue color and were localized on corticomedullar junction of the thymus. These cells were of different intensity of coloring and were shaped in oval, circle or irregular forms. NADPH-d positive nerve fibers were observed in perivascular topography. They were marked more strongly in the case of control group. The result of application of RA to gravid rats was that the birth weights of newborn rats and their thymuses were smaller, but without statistically significance.

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 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. The major effect of BetA-induced NO appears to be involved in maintenance of the immune system ( 38 – 40 ) and the current results support other reports in which the presence of NO was demonstrated in the immune system ( 33 , 41 ).…”

“…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 ).…”

“…There are three isoforms of NO synthases (NOSs), which are neuronal (nNOS), inducible (iNOS) and endothelial (eNOS), and they are responsible for the synthesis of NO from the amino acid, l-arginine ( 30 ). Previous studies have demonstrated that all three isoforms express enzymatic activity of NADPH-d ( 31 , 32 ), and indicated the expression pattern of NADPH-d is an indirect indication of the presence of NOS and NO ( 30 , 33 ). Therefore NADPH-d activity has been used as a marker for NOS.…”