The aim of the present work was to perform a comparative immunohistochemical study of the ocular lens in normal conditions and after formation of various type of age-related cataract in humans. The control group consisted of lenses from young men dying from accidents and serving as corneal donors (n = 10, not more than one hour after death). Lenses from patients (aged 60-70 years) undergoing surgery for cortical (n = 20) and nuclear (n = 20) cataracts were studied. The investigations demonstrated plasticity in the phenotype of lens cells in age-related cataract. Changes in the phenotype of lens cells were found to depend on the type of age-related cataract. Development of the cortical variant of age-related cataract was associated with positive reactions with monoclonal antibodies to neuron-specific enolase, S-100 protein, and vimentin only within the lens cortex. Formation of age-related nuclear cataract was associated with positive reactions with antibodies to alpha-smooth muscle actin and pancytokeratin, which were detected only in the lens nucleus. This provides evidence of the need to develop a differential approach to the treatment of different types of age-related cataract.

Mast cells (MCs) are densely granulated cells of myeloid origin and are a part of immune and neuroimmune systems. MCs have been detected in the endolymphatic sac of the inner ear and are suggested to regulate allergic hydrops. However, their existence in the cochlea has never been documented. In this work, we show that MCs are present in the cochleae of C57BL/6 mice and Wistar rats, where they localize in the modiolus, spiral ligament, and stria vascularis. The identity of MCs was confirmed in cochlear cryosections and flat preparations using avidin and antibodies against c-Kit/CD117, chymase, tryptase, and FcεRIα. The number of MCs decreased significantly during postnatal development, resulting in only a few MCs present in the flat preparation of the cochlea of a rat. In addition, exposure to 40 µM cisplatin for 24 h led to a significant reduction in cochlear MCs. The presence of MCs in the cochlea may shed new light on postnatal maturation of the auditory periphery and possible involvement in the ototoxicity of cisplatin. Presented data extend the current knowledge about the physiology and pathology of the auditory periphery. Future functional studies should expand and translate this new basic knowledge to clinics.

Fluorescent granular cells of the thymus lobule containing neurotransmitter monoamines express Ia antigen and S-100 protein, which attests to their macrophage origin; positive staining with aldehyde fuchsin points to secretion of peptide hormones by these cells. These facts and the absence of phagocytic activity allow to identify these cells as dendritic macrophages.

Morphological and immunohistochemical study was performed to evaluate the effect of orchiectomy on structures of the thymus expressing major histocompatibility complex class II (MHC-II) proteins. Male sex hormone deficiency in the organism led to an increase in the number of MHC-II+ cells in the medulla and cortex of the thymic lobule. At the same time, the count of these cells in the corticomedullary zone decreased after orchiectomy. These changes modify homeostasis and activate immune processes.