The mast cell mediators and distribution of lung mast cells in rats are often discussed in experimental studies on pulmonary fibrotic and allergic processes associated with changes in numbers of these cells, but information on the normal distribution of metachromatic and tryptase-positive mast cells in the interalveolar septa is scarce. There are no data on the presence of ghrelin in lung mast cells as well as the age-specific features of localisation and the number of mast cells in the interalveolar septa in rats of different ages. Therefore, the purpose of the present study was to determine the distribution of metachromatic, tryptase-, and ghrelin-positive mast cells in the interalveolar septa in 20 day-, 3 month- and 1 year-old rats. Tissue sections stained with toluidine blue had been taken from the left lung to visualise metachromasia and immunohistochemical expression of tryptase and ghrelin. The results showed that the amount of metachromatic mast cells in the interalveolar septa was significantly lower than that of tryptase- and ghrelin-positive cells. This allowed suggesting that mast cells were permanent occupants of the rat lung parenchyma and, on the other hand, the expression of ghrelin in their granules was most likely related to the synthesis of this protein. Our study showed that immunohistochemical identification by tryptase expression was more accurate than toluidine blue staining.

The aim of this study was to investigate mast cell (MCs) distribution in the vicinity of the needle tract formed after acupuncture in Zusanli (ST36) acupoint in rats. MCs were detected by histochemistry, immunohistochemistry and transmission electron microscopy, and evaluated quantitatively. It was established that after acupuncture in ST36 acupoint the integrity of the epithelium, dermis, subcutaneous connective tissue, fascia, epimysium and striated muscles was disrupted and folded to the direction of the needle tract. In the thickened connective tissue MCs were observed close to the needle tract, without visible differences in their number along the tract, but most of them were with signs of degranulation, possibly due to acupuncture. It could be presumed that acupuncture in ST36 caused recruitment and activation of MCs followed by degranulation which most probably influenced the local microenvironment.

This paper is a short review of scientific literature on lung mast cells in norm and pathology that shows the current state of this problem. Particular attention is paid to the quantity, location and arrangement of the mast cells. The mast cells are a part of immune system whom origin are myeloid stem cells. They are a kind of white blood cells. Many authors from the 19th century to the present day have traced and described the role of mast cells in the human body, their structure and changes depending on the functional state of the organism. Paul Ehrlich is the first author that described in his doctoral thesis the mast cells as effectors of allergy particularly in the beginning of reaction and in acute phase of the process. Research has continued through out the 20th century and researchers' efforts are primarily focused on clarifying the structure and function of mast cells and identifying their role in pathological responses in the human body. Mast cells are found in all organs, but they predominate in peripheral blood, spleen and bone marrow. There are cells in the rat skin that live for about 12 weeks, and more recent studies have found that proliferation of mature mast cells is caused by various factors.

Some acupuncture effects are considered to be caused by interaction with nerve structures in and around the acupoints. The aim of the present study was to investigate the nerve structures that interact with the needle in acupuncture and to present their distribution in acupoint tissues. To do this, the microscopic anatomy and its alterations in the vicinity of the needle tract formed after experimental acupuncture in ST36 acupoint in rats were described by histological and immunohistochemical methods. Free nerve endings were seen in the epidermis, and surrounding hair follicles and sebaceous glands in the dermis. Muscle spindles and larger nerve fibres close to blood vessels were also observed deeper, in the muscular plane. Needling of the acupoint caused destruction and displacement of hair follicles together with their free nerve endings. Deeper, some muscle spindles and smaller nerves were displaced and disrupted. Larger nerves were not destroyed, but rather pushed aside by the needle. Furthermore, needle impact also caused degranulation of mast cells near the needle tract. The findings suggest multiple ways of interaction between acupuncture needle and the nerve structures of the acupoint. Acupuncture combines destruction, disruption and displacement of nerve structures, together with additional interaction with mast cells. Those mechanisms are involved in eliciting the needling sensation and are possibly associated with the systemic effect of acupuncture.

This article sheds light on some features of ghrelin (GHR)- and tryptase (Try)-positive mast cells (MCs) distribution in human lung of preterm newborns with respiratory distress syndrome (RDS). GHR possessed anti-inflammatory activity and reliable therapeutic properties in some lung diseases. So far, GHR expression has been defined predominantly in neuroendocrine cells of bronchial mucosa in fetal and infant lungs. Lung tissue from 8 dead newborns with RDS were investigated immunohistochemically with anti-GHR and anti-Try antibodies. The number of GHR+ and Try+ MCs was determined in three locations –bronchi, bronchiole and in alveolar septa. MCs were more numerous around main bronchi with diminishing numbers around bronchiole and in alveolar septa. The number of MCs in the latter was increased in newborns with pneumonia. The number of GHR+ MCs in alveolar septa was lower in newborns with RDS as compared to newborns with RDS combined with pneumonia (2.83 ± 1.13 vs 4.81 ± 2.6, p < 0.001). The amount of Try+ MCs along bronchial wall was significantly more than GHR+ MCs in RDS newborns (6.97 ± 4.53 vs 3.85 ± 4.30, p = 0.001). It could be supposed that pulmonary MCs increased in newborn lungs in inflammatory process. MCs in human lung contained GHR peptide that had immunomodulatory function and participated in hormone regulation of inflammation.