Conventionally, the size, shape, and biomechanics of cartilages are determined by their voluminous extracellular matrix. By contrast, we found that multiple murine cartilages consist of lipid-filled cells called lipochondrocytes. Despite resembling adipocytes, lipochondrocytes were molecularly distinct and produced lipids exclusively through de novo lipogenesis. Consequently, lipochondrocytes grew uniform lipid droplets that resisted systemic lipid surges and did not enlarge upon obesity. Lipochondrocytes also lacked lipid mobilization factors, which enabled exceptional vacuole stability and protected cartilage from shrinking upon starvation. Lipid droplets modulated lipocartilage biomechanics by decreasing the tissue's stiffness, strength, and resilience. Lipochondrocytes were found in multiple mammals, including humans, but not in nonmammalian tetrapods. Thus, analogous to bubble wrap, superstable lipid vacuoles confer skeletal tissue with cartilage-like properties without "packing foam-like" extracellular matrix.

A model was developed, on the basis of which the features of healing of a full-thickness skin wound were studied in laboratory rats using macro-, micro- and ultramicroscopic methods. It was found that during this process, two borders are formed on the surface of the wound ‒ one on the edge of the dermis and the second on the edge of the epidermis. It is shown that a granulation tissue can be formed not only due to the restructuring of fibrin, but also due to the reorganization of a subcutaneous tissue. It is hypothesized that the wound contraction occurs not only due to the contraction of collagen fibrils by myofibroblasts, but also due to the retraction of collagen fibers in the cytoplasm of these cells. Attention is drawn to the restoration of the elastic layer as an essential component of the skin regenerate. The reasons for the appearance of a longitudinal elongated shape and orientation along the sagittal line of the scar, which remains for life at the site of the former skin damage, are explained.

Macroscopic, histological, electron microscopic, microbiological, and immunological methods were used to study the healing of full-thickness skin wounds in laboratory rats under the influence of quercetin and its complex with 2-hydroxypropyl-β-cyclodextrin. It was revealed that under the influence of quercetin, the wound was completely covered with the epidermis almost a day earlier than in the control, and under the influence of a complex with 2-hydroxypropylβ-cyclodextrin 2.2 days earlier (p < 0.02). This was mainly due to the acceleration of marginal epidermization. There was no positive effect on the wound contraction. Quercetin and especially its complex with cyclodextrin had a stimulating effect on the phagocytic and metabolic activity of neutrophils both on the wound surface and in the blood of animals. The bacterial microflora present on the wound surface during healing coincided with the microflora of the intact skin. Neither the quercetin, nor the quercetin-2-hydroxypropyl-β-cyclodextrin significantly affected its composition.

A method for revealing genetic affinity between laboratory rats has been developed, which is based on the transplantation of ear skin-chondrocyte allografts onto the surface of a full-thickness skin defect. On the example of Wistar rats (laboratory rats were taken from three research institutes), it was shown that the rejection of allografts occurs in the interval between 8 and 21 days with the same genetic differences that existed between the animals. However, at the same time, only those structures of ear allografts such as the dermis, epidermis and its derivatives die and are rejected, but the layers of chondrocytes are submerged under the granulation tissue and remain in a viable position for at least 210 days. The latter phenomenon is probably due to the membranes that cover the chondrocytes and act as an immunological barrier.

The aim of the study, performed on 65 Wistar rats, was to develop a new model and, as an example, use it to identify the extent to which quercetin and the quercetin-2-hydroxypropyl-β-cyclodextrin nanocomplex, applied to the wound, affect the engraftment of skin autografts. Grafts were obtained from the ear shells of animals, and graft’s survival rate was assessed by the degree of inhibition of wound contraction. It is shown that the latter depends on the area of grafts and the time after which they were located on the wound surface after its creation. It was shown that quercetin worsens, and quercetin-2- hydroxypropyl-β-cyclodextrin does not impair the ability of the wound surface to accept the graft.

Wounds in mammals commonly heal by scarring but retain latent capacity to regenerate. In this issue of Developmental Cell, Brewer, Nelson et al. reveal that heightened ability of spiny mice to regenerate after injury is attributed to molecular changes in the Hippo-YAP (yes-associated protein) pathway that protect wound fibroblasts from a persistent contractile state.

The possibility of using vitamin D to normalize the histological structure of the spleen changed under the influence of prednisolone in rats was studied. The animals were subjected to the intragastric administration of saline and either prednisolone (5 mg/kg b. w.) or its combination with vitamin D (800 IU/kg) daily for 3 weeks. The results of morphometric analysis of spleen slices reveal that the administration of prednisolone leads to a significant decrease in spleen sizes, white pulp volume, and in sizes of germinal centers of lymphatic follicles within the white pulp, and to an increase in the number of megakaryocytes in the red pulp. Vitamin D alleviates histological changes due to the prednisolone treatment, in particular the substantial restoration in sizes of germinal centers in the spleen has been found. The data obtained suggest the benefits of further studies of possible mechanisms of vitamin D to normalize immunological and hematopoietic functions in subjects subjected to glucocorticoid treatment.

Mushroom Phallus impudicus is traditionally used in Asia and Northern Europe as a remedy of folk medicine.This review summarizes our own results on the artificial cultivation of the P.impudicus mycelium and some data on the study of the biological activity of polysaccharides isolated from this mycelium.The cultural-morphological and physiological-biochemical properties of the mycelium of the new fungal strain of P.impudicus were studied.The optimization of the nutrient medium composition and cultural conditions enabled to increase the biomass yield by 1.3-fold,and the contents of polysaccharides by 1.5 to 1.7-fold.The polysaocharides isolated from this mycelium possessed immunomodulating properties in vitro as well as in vivo in experimental rats with streptozotocin-induced diabetes.The ointment containing 10％ P.impudicus polysaccharides enhanced cutaneous wound healing in experimental rats,accelerating epithelialization,contraction and growth of granulation tissue as compared to the ointment base.Taken together,polysaccharides ofP.impudicus mycelium are promising raw material for the development of functional food as well as new therapeutic and prophylactic drugs.

. The aim of this study was to evaluate the effects of quercetin (QC) and its complex with 2-hydroxypropyl-β-cyclodextrin (QECD) in healing burn related skin wounds in the rat model. Male Wistar rats were subjected to third-degree burn injury of skin in the interscapular area using a metal rod heated to 80 °C. The area of the skin which the burn was applied to was secured from the surroundings by the protective chamber. In order to estimate the efficacy of different treatment modalities the experiments were carried out in two stages. On first stage of the study, the group of animals (n = 21) was subjected to burn injury and the wound surface was not affected with additional procedures except the substances for treatment being applied. During the second stage of the study with another group of animals (n = 18) the removal of necrotic tissue was carried out over the period of 3 to 7 days. The progress of the wound healing was followed by performing morphometric analyses in order to determine complete re-epithelialization. The phagocytic index of neutrophils was determined in washouts from the wounds during the healing process. The animals used on the first stage of the study were sacrificed at day 21 of the experiment and those on the second stage at day 43 and the tissues were subjected to histological examination. The amounts of white blood cells and phagocytic index of neutrophils were calculated in blood samples followed by the measurements of metabolic activities of neutrophils. The removal of necrotic tissue has been found to promote better wound healing caused by thermal exposure. No reliable evidence has been obtained on QC or QECD abilities to significantly accelerate the burn wound epithelialization. The square of the secondary wound scab covered the damaged skin surface has been found to be decreased in the first group of animals on the 14th day followed by the exposure while the rate of wound epithelialization has been found to be increased in the second group of animals at the final stage of wound healing under the treatment with substances being investigated. As a result the ability of QE and QECD to normalize the white blood cell differential, phagocytic and metabolic activities of neutrophils recruited to a wound and neutrophil blood levels has been found.

Hairs and feathers are textbook examples of the convergent evolution of the follicular appendage structure between mammals and birds. While broadly recognized for their convergent thermoregulatory, camouflage and sexual display functions, hairs and feathers are rarely thought of as deadly defence tools. Several recent studies, however, show that in some species of mammals and birds, the integument can, in fact, be a de facto lethal weapon. One mammalian example is provided by African crested rats, which seek for and chew on the bark of plants containing the highly potent toxin, ouabain. These rats then coat their fur with ouabain-containing saliva. For efficient toxin retention, the rodents have evolved highly specialized fenestrated and mostly hollow hair shafts that soak up liquids, which essentially function as wicks. On the avian side of the vertebrate integumental variety spectrum, several species of birds of New Guinea have evolved resistance to highly potent batrachotoxins, which they acquire from their insect diet. While the mechanism of bird toxicity remains obscure, in a recently published issue of the journal, Dumbacher and Menon explore the intriguing idea that to achieve efficient storage of batrachotoxins in their skin, some birds exploit the basic permeability barrier function of their epidermis. Batrachotoxins become preferentially sequestered in their epidermis and are then transferred to feathers, likely through the exploitation of specialized avian lipid-storing multigranular body organelles. Here, we discuss wider implications of this intriguing concept.