Effects and mechanism of lncRNA-27785.1 that regulates TGF-ß1 of Sika deer on antler cell proliferation.

Transforming growth factor (TGF-ß) plays an important role in the development of deer antlers. The purpose of this study was to investigate the role of long noncoding RNA in the transcriptional regulation of TGF-ß1 and its relationship with the proliferation and differentiation of antler chondrocytes. High-throughput sequencing was used to screen lncRNAs related to TGF-ß1. Next, the overexpression plasmid and interference sequence of target lncRNA27785.1 were constructed and transfected into chondrocytes. We found that lncRNA27785.1 inhibited the proliferation and migration of chondrocytes and delayed the transition of cells from G1 to S phase. qRT-PCR and Western blot analysis indicated that the overexpression of lncRNA27785.1 may downregulate mRNA and protein expression of TGF-BR2, Smad3, pSmad3, and Smad4. Our findings highlight lncRNA27785.1 as an inhibitor of chondrocytes proliferation and differentiation by negatively regulating the TGF-ß/Smad signaling pathway; this implicates an important regulatory role for long noncoding RNA in the regeneration of antler.

PTN-PTPRZ signalling is involved in deer antler stem cell regulation during tissue regeneration.

A growing deer antler contains a stem cell niche that can drive endochondral bone regeneration at up to 2 cm/day. Pleiotrophin (PTN), as a multifunctional growth factor, is found highly expressed at the messenger RNA level within the active antler stem cell tissues. This study aims to map the expression patterns of PTN protein and its receptors in a growing antler and investigate the effects of PTN on antler stem cells in vitro. Immunohistochemistry was employed to localise PTN/midkine (MDK) and their functional receptors, protein tyrosine phosphatase receptor type Z (PTPRZ), anaplastic lymphoma kinase (ALK), NOTCH2, and integrin αV ß3, on serial slides of the antler growth centre. PTN was found to be the dominantly expressed growth factor in the PTN/MDK family. High expression of PTPRZ and ALK co-localised with PTN was found suggesting a potential interaction. The high levels of PTN and PTPRZ reflected the antler stem cell activation status during the regenerative process. When antler stem cells were cultured in vitro under the normoxic condition, no PTN protein was detected and exogenous PTN did not induce differentiation or proliferation but rather stem cell maintenance. Collectively, the antler stem cell niche appears to upregulate PTN and PTPRZ in vivo, and PTN-PTPRZ signalling may be involved in regulating antler stem cell behaviour during rapid antler regeneration.

Antler stem cells as a novel stem cell source for reducing liver fibrosis.

Liver fibrosis results from collagen fiber deposition. Antler stem cells (ASCs) naturally in vivo differentiate into cartilage, which is only made of Col II in collagen component; whereas liver fibrosis is caused by over-abundance of Col I and III. In addition, ASCs can effectively promote regenerative wound healing in which tissue contains very few collagen fibers (Col I). In this study, we investigate the therapeutic effects of ASCs in a rat model of CCl4-induced liver fibrosis. Rats were treated with ASCs for 4 weeks in vivo, then biochemical and histopathological analyses were performed. Furthermore, we established cell co-culture systems of hepatic stellate cells (HSCs) and ASCs and of M1 macrophages and ASCs in vitro. Mesenchymal stem cells (MSCs) were used as a positive control. The results showed that ASC transplantation alleviated liver fibrosis effectively as evidenced by reduced collagen accumulation, decreased fatty degeneration, increased hepatocyte regeneration, decreased inflammation and significantly enhanced liver function; moreover, ASCs decreased the expression of pro-fibrogenic factors including TGF-ß and α-SMA. Additionally, our study showed that ASCs inhibit HSC activation and proliferation by controlling the expression of MMPs, TIMP1, TGF-ß, α-SMA and COL1A2 involved in these processes. Our results suggested that ASCs alleviate liver fibrosis effectively and inhibit HSC activation. Thus, ASCs may serve as a novel stem cell source for the treatment of liver fibrosis in the clinic.

Single-cell transcriptome provides novel insights into antler stem cells, a cell type capable of mammalian organ regeneration.

Antler regeneration, a stem cell-based epimorphic process, has a potential as a valuable model for regenerative medicine. A pool of antler stem cells (ASCs) for antler development is located in the antlerogenic periosteum (AP). However, whether this ASC pool is homogenous or heterogeneous has not been fully evaluated. In this study, we produced a comprehensive transcriptome dataset at the single-cell level for the ASCs based on the 10× Genomics platform (scRNA-seq). A total of 4565 ASCs were sequenced and classified into a large cell cluster, indicating that the ASC resident in the AP are likely to be a homogeneous population. The scRNA-seq data revealed that tumor-related genes were highly expressed in these homogeneous ASCs, i.e., TIMP1, TMSB10, LGALS1, FTH1, VIM, LOC110126017, and S100A4. Results of screening for stem cell markers suggest that the ASCs may be considered as a special type of stem cell between embryonic (CD9) and adult (CD29, CD90, NPM1, and VIM) stem cells. Our results provide the first comprehensive transcriptome analysis at the single-cell level for the ASCs and identified only one major cell type resident in the AP and some key stem cell genes, which may hold the key to why antlers, the unique mammalian organ, can fully regenerate once lost.

WNT4 acts downstream of BMP2 to mediate the regulation of ATRA signaling on RUNX1 expression: Implications for terminal differentiation of antler chondrocytes.

Although ATRA is involved in regulating the proliferation and differentiation of chondrocytes, its underlying mechanism remains unknown. Here we showed that ATRA could stimulate the proliferation of antler chondrocytes and expression of COL X and MMP13 which were two well-known markers for hypertrophic chondrocytes. Silencing of CRABP2 prevented the induction of ATRA on chondrocyte terminal differentiation, while overexpression of CRABP2 exhibited the opposite effects. CYP26A1 and CYP26B1 weakened the sensitivity of antler chondrocytes to ATRA. Further analysis evidenced that ATRA might induce chondrocyte terminal differentiation and modulate the expression of BMP2, WNT4, and RUNX1 through RARα/RXRα. Knockdown of BMP2 enhanced the induction of ATRA on the expression of COL X and MMP13, whereas overexpression of BMP2 abrogated this effectiveness. WNT4 might mediate the effects of ATRA and BMP2 on chondrocyte terminal differentiation. Dysregulation of BMP2 impaired the regulation of ATRA on WNT4 expression. Administration of ATRA to antler chondrocytes transfected with RUNX1 siRNA failed to induce the differentiation. Conversely, rRUNX1 strengthened the stimulation of ATRA on the expression of COL X and MMP13. Simultaneously, RUNX1 was a downstream effector of BMP2 and WNT4 in chondrocyte terminal differentiation. Moreover, WNT4 might play an important role in the crosstalk between BMP2 and RUNX1. Attenuation of BMP2 or WNT4 enhanced the interaction between ATRA and RUNX1, while constitutive expression of BMP2 or WNT4 reversed the regulation of ATRA on RUNX1. Collectively, WNT4 may act downstream of BMP2 to mediate the effects of ATRA on the terminal differentiation of antler chondrocytes through targeting RUNX1.

Lateralization during lateral display and its relationship with antler size and symmetry in fallow deer (Dama dama).

Individuals often display a preference for one side of their body during aggressive encounters. This may be a lateralized preference for using one structure of a bilateral trait during display or physical attack, or for keeping the opponent in one visual field. Alternatively, it may be the case that behavioural lateralization and the degree of symmetry expressed by bilateral structures are correlated forms of developmental instability. We examined whether there was an association between lateralization during a lateral display and different measurements of antler size and symmetry (beam length, beam circumference, brow tine length and coronet circumference). Three models addressed different structural measures: the right antler, the larger antler and antler symmetry. Results showed that beam length was negatively associated with behavioural lateralization irrespective of structural measure. A second analysis using a composite score of the four antler measurements, one for each structural measure, showed that only antler symmetry was negatively associated with lateralization during lateral display. Therefore, our second prediction was supported. We discuss these findings in relation to predator detection capability and stress reduction in prey species such as the fallow deer.

ATRA Signaling Regulates the Expression of COL9A1 through BMP2-WNT4-RUNX1 Pathway in Antler Chondrocytes.

Although all-trans retinoic acid (ATRA) is involved in the regulation of cartilage growth and development, its regulatory mechanisms remain unknown. Here, we showed that ATRA could induce the expression of COL9A1 in antler chondrocytes. Silencing of cellular retinoic acid binding protein 2 (CRABP2) could impede the ATRA-induced upregulation of COL9A1, whereas overexpression of CRABP2 presented the opposite effect. RARα agonist Am80 induced the expression of COL9A1, whereas treatment with RARα antagonist Ro 41-5253 or RXRα small-interfering RNA (siRNA) caused an obvious blockage of ATRA on COL9A1. In antler chondrocytes, CYP26A1 and CYP26B1 weakened the sensitivity of ATRA to COL9A1. Simultaneously, Bone morphogenetic protein 2 (BMP2) and WNT4 mediated the regulation of ATRA on COL9A1 expression. Knockdown of WNT4 could abrogate the inhibitory effect of BMP2 overexpression on COL9A1. Conversely, constitutive expression of WNT4 reversed the upregulation of COL9A1 elicited by BMP2 siRNA. Together these data indicated that WNT4 might act downstream of BMP2 to mediate the effect of ATRA on COL9A1 expression. Further analysis evidenced that attenuation of runt-related transcription factor 1 (RUNX1) could prevent the stimulation of ATRA on COL9A1 expression, while exogenous rRUNX1 further enhanced this effectiveness. Moreover, RUNX1 might serve as an intermediate to mediate the regulation of BMP2 and WNT4 on COL9A1 expression. Collectively, ATRA signaling might regulate the expression of COL9A1 through BMP2-WNT4-RUNX1 pathway.

The Regulatory Mechanism of MLT/MT1 Signaling on the Growth of Antler Mesenchymal Cells.

Melatonin (MLT) plays an important role in regulating the physiological cycle of seasonal breeding animals. Melatonin receptor I (MT1) is effectively expressed in the cambium layer of deer antler. However, the function and metabolic mechanism of MLT/MT1 signaling in the mesenchymal cells of sika deer remain to be further elucidated. In this work, we detected the effects of MLT/MT1 signaling on mesenchymal cells proliferation and the interaction between MLT/MT1 and IGF1/IGF1-R signaling. The results show that (1) deer antler mesenchymal cells actually express MT1; (2) exogenous melatonin significantly promotes mesenchymal cells proliferation, while MT1 knock-down significantly impairs the positive effects of melatonin; and (3) melatonin significantly enhanced IGF1/IGF1-R signaling, as both the expression of IGF1 and IGF-1R increased, while MT1 knock-down significantly decreased IGF1-R expression and IGF1 synthesis. In summary, these data verified that MLT/MT1 signaling plays a crucial role in antler mesenchymal proliferation, which may be mediated by IGF1/IGF1-R.

Antler velvet is thicker in adult than in yearling pampas deer (Ozotoceros bezoarticus): a histological study.

BACKGROUND: Antlers are lined by soft velvet tissue during antler growth. Later, the velvet is shed before rut onset. There are no detailed histological descriptions of the growing velvet, nor whether the velvet changes according to stag age. Our aims were to: 1) describe the basic histology of pampas deer antler velvet from adult and yearling males; and 2) determine the influence of age and time of antler growth on velvet's tissues morphometry. MATERIALS AND METHODS: Samples were collected from 10 stags allocated in two groups, either adult (3-5 years old, n = 5) or yearling males (2 years old, n = 5). The day of antler cast was recorded for each animal. In spring, the stags were anaesthetised and velvet samples were collected from the third tine's distal end. Samples were described qualitatively and a restricted morphometrical analysis of the antler velvet was performed. RESULTS: The number of keratinocyte layers and the thicknesses of: total epidermis, corneum, intermediate and basale epidermal strata, total dermis, superficial and deep dermis were determined. Age and days after antler casting positively influenced in conjunction epidermal thickness (p = 0.037), and tended to influence both stratum intermedium (p = 0.076) and stratum corneum (p = 0.1) thicknesses. Age influenced stratum corneum thickness (p = 0.04). The pampas deer antler velvet lacked both sweat glands and arrector pili muscles. CONCLUSIONS: The deep dermis was densely irrigated but displayed abundant and well developed collagen bundles. Both total epidermal and stratum corneum thicknesses related positively to the age of the animals but were not to the time since antler cast.

MicroRNA profiling of antler stem cells in potentiated and dormant states and their potential roles in antler regeneration.

MicroRNAs (miRNAs) can effectively regulate gene expression at the post-transcriptional level and play a critical role in tissue growth, development and regeneration. Our previous studies showed that antler regeneration is a stem cell-based process and antler stem cells reside in the periosteum of a pedicle, the permanent bony protuberance, from which antler regeneration takes place. Antlers are the only mammalian organ that can fully regenerate and hence provide a unique opportunity to identify miRNAs that are involved in organ regeneration. In the present study, we used next generation sequencing technology sequenced miRNAs of the stem cells derived from either the potentiated or the dormant pedicle periosteum. A population of both conserved and 20 deer-specific miRNAs was identified. These conserved miRNAs were derived from 453 homologous hairpin precursors across 88 animal species, and were further grouped into 167 miRNA families. Among them, the miR-296 is embryonic stem cell-specific. The potentiation process resulted in the significant regulation (>±2 Fold, q value <0.05) of conserved miRNAs; 8 miRNA transcripts were down- and 6 up-regulated. Several GO biology processes and the Wnt, MAPK and TGF-beta signaling pathways were found to be up-regulated as part of antlerogenic stem cell potentiation process. This research has identified miRNAs that are associated either with the dormant or the potentiated antler stem cells and identified some target miRNAs for further research into their role played in mammalian organ regeneration.

Antlerogenic stem cells: molecular features and potential in rabbit bone regeneration.

AIM: (i) To assess the expression profiles of stem cell-associated markers including Oct4, Sox2, Klf4, Nanog, C-myc, Stat3 and Cd9, (ii) analyze the nanotopography of the MIC-1 stem cells and (iii) evaluate the efficiency of live stem cell implants and stem cell culture derivatives on the regeneration of bone deficiencies in rabbit mandibles. MATERIALS AND METHODS: The expression profiles of stem cell-associated genes, including Oct4, Sox2, Klf4, Nanog, C-myc, Stat3 and CD9 were assessed using reverse transcription polymerase chain reaction and flow cytometry. Nanotopography of the antlerogenic MIC-1 cell lineage was analyzed using atomic force microscopy. The effect of MIC-1 stem cells, their homogenate and supernatant on the regeneration of bone deficiencies in rabbit mandibles was evaluated using histological analysis. The effect of MIC-1 stem cells and stem cell-based derivatives on the immune responses of the animals was assessed by analyses of acute phase protein levels (haptoglobin and fibrinogen). RESULTS: We found that the MIC-1 cells isolated from the apical regions of growing antlers exhibited molecular features that were characteristics of pluripotent stem cells. Using atomic force microscopy, we determined the details of the cell surface morphologies with a particular emphasis on the patterns of formation of plasma extensions for interlinking adjacent cells. We also demonstrated that not only implanted stem cells but also cell homogenates and cell post-culture supernatants have potential in the regeneration of bone deficiencies in the rabbit mandible. CONCLUSIONS: Our findings indicate that the use of both antlerogenic stem cell implants and the preparations derived from the cells offer alternative approaches to those based on autologous stem cells in the biological stimulation of osteogenesis and in bone regeneration.

Direct localisation of molecules in tissue sections of growing antler tips using MALDI imaging.

The astonishing growth rate of deer antlers offers a valuable model for the discovery of novel factors and regulatory systems controlling rapid tissue growth. Numerous molecules have been identified in growing antlers using a variety of techniques. However, little is known about the spatial distribution of these molecules in situ. A technique that has the potential to help in this regard is direct proteomic analysis of tissue sections by matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS). The present study applied this technique to spatially map molecules in antler tissue sections. Two protonated molecular ions were selected: m/z 6679 and m/z 6200 corresponding to VEGF and thymosin beta-10, respectively. Superimposition of the respective ion images on to histologically stained samples showed distinct spatial distribution across the antler tissue sections which were consistent with the previous reports using in situ hybridization. Two other molecular ions specifically m/z 8100 and m/z 11,800 were also selected, corresponding to reported masses of urocortin precursor and thioredoxin, respectively. As the spatial distribution of these proteins is not specifically known, MALDI-IMS was used as a potential technique to obtain information on their distribution on antler tips. The presence of all these molecules in deer antlers were further confirmed using LC-MS/MS data. The present study also demonstrated that MALDI-IMS could be further used to image antler sections with an extended ion mass range of up to m/z 45,000, thus potentially increasing the ability to discover the distribution of a larger set of molecules that may play an important role in antler growth. We have thus demonstrated that MALDI-IMS is a promising technique for generating molecular maps with high spatial resolution which can aid in evaluating the function of novel molecules during antler growth.

Conditioned Media from Deer Antler Stem Cells Effectively Alleviate Type 1 Diabetes Mellitus Possibly via Inhibiting the NF-κB Signaling Pathway.

BACKGROUND: Type 1 diabetes mellitus (T1D) represents a severe threat to human health. Persistent hyperglycemia and dyslipidemia can lead to damaged liver function, while effective interventions for these complications are currently lacking. Deer antler stem cells (AnSCs), a novel type of adult stem cells, significantly reduced liver injury, which was speculated to be achieved through the paracrine pathway. METHODS: In this study, AnSC-conditioned medium (AnSC-CM) was used to treat C57BL/6 mice with T1D symptoms induced by streptozotocin (STZ). The therapeutic effects of AnSC-CM on T1D were evaluated, and the underlying mechanism was investigated. RESULTS: It was shown that AnSC-CM alleviated the T1D symptom: decreased body weight, increased blood glucose levels and islet lesions, and reduced insulin secretion. Moreover, AnSC-CM treatment improved liver function and mitigated liver injury in T1D mice. Impressively, the therapeutic effects of AnSC-CM on T1D were better than those of bone marrow mesenchymal stem cell-CM (BMSC-CM). The mechanistic study revealed that AnSC-CM significantly downregulated the NF-κB signaling pathway in both pancreatic and liver tissues. CONCLUSIONS: Therapeutic effects of AnSC-CM on STZ-induced T1D and liver injury may be achieved through targeting the NF-κB signaling pathway.

Effects of PTHrP on chondrocytes of sika deer antler.

Parathyroid-hormone-related peptide (PTHrP) is an important regulator of chondrocyte differentiation in growth plates but little is known about its role in deer antler cartilage. The aim of the present study was to use the deer antler as a model to determine the possible role of PTHrP in regulating chondrocyte differentiation of deer antler. PTHrP and its receptor PTH1R mRNA were highly expressed in the perichondrium and cartilage of sika deer antler, as shown by in situ hybridization. Chondrocytes of deer antler were identified by toluidine blue staining of glycosaminoglycan and immunocytochemical staining of type II collagen (Col II). Treatment with PTHrP (1-34) reduced the expression of prehypertrophic chondrocyte marker Col IX and hypertrophic chondrocyte marker Col X. In order to confirm the mechanism of action of PTHrP, we initially examined the expression of cyclin D1, Bcl-2 and runt-related transcription factor 2 (Runx2) in sika deer antler by in situ hybridization and found that cyclin D1, Runx2 and Bcl-2 mRNA were also expressed in antler chondrocytes. Exogenous PTHrP induced the expression of cyclin D1 and Bcl-2 mRNA by various signalling pathways, whereas it inhibited Runx2 expression through PKA, p38MAPK, MEK and PI3K signalling pathways. Thus, PTHrP might promote the proliferation of antler chondrocytes and prevent their differentiation; it might furthermore influence the growth and development of sika deer antler.

Stem cells drive antler regeneration.

Understanding the rapid growth of deer antlers could have applications in medicine.

A population of stem cells with strong regenerative potential discovered in deer antlers.

The annual regrowth of deer antlers provides a valuable model for studying organ regeneration in mammals. We describe a single-cell atlas of antler regrowth. The earliest-stage antler initiators were mesenchymal cells that express the paired related homeobox 1 gene (PRRX1+ mesenchymal cells). We also identified a population of "antler blastema progenitor cells" (ABPCs) that developed from the PRRX1+ mesenchymal cells and directed the antler regeneration process. Cross-species comparisons identified ABPCs in several mammalian blastema. In vivo and in vitro ABPCs displayed strong self-renewal ability and could generate osteochondral lineage cells. Last, we observed a spatially well-structured pattern of cellular and gene expression in antler growth center during the peak growth stage, revealing the cellular mechanisms involved in rapid antler elongation.

Deer antlers - a model of mammalian appendage regeneration: an extensive review.

BACKGROUND: compared with other vertebrate taxa, mammals possess a very limited capacity for appendage regeneration. The antlers of deer are an exception in that they are periodically lost and fully regenerated throughout the life of an individual. OBJECTIVE: in this paper we compare certain aspects of antler regeneration with regenerative processes in other vertebrates. METHODS: review of the literature. RESULTS: recent studies suggest that antler regeneration is a stem cell-based process and that these stem cells are located in the pedicle periosteum. There is evidence that signaling pathways known to operate during appendage regeneration in other vertebrates are also activated during antler regeneration. There are, however, also differences between antlers and other systems of epimorphic regeneration. Thus, contrary to amphibian limb regeneration, signaling from the wound epidermis appears not to be of crucial importance for antler regeneration. Healing of the casting wound typically involves no or only minor scarring, making antlers interesting subjects for researchers attempting to reduce scar formation during wound healing in humans. The fact that despite their enormous growth rate the antlers of intact and castrated deer appear to be resistant to malignant transformation furthermore offers research opportunities for cancer biology. CONCLUSIONS: studying antler renewal as an example of mammalian appendage regeneration may provide crucial information for regenerative medicine to achieve its ultimate goal of stimulating limb regeneration in humans. A deeper understanding of the developmental mechanisms involved in antler renewal can also be useful for controlling induced regeneration processes in mammals.

Antlerogenic stem cells extract accelerate chronic wound healing: a preliminary study.

BACKGROUND: Chronic wounds constitute a significant medical and social problem. Chronic wound treatment may be supported by various techniques, such as negative pressure therapy, phototherapy or stem cells therapy, yet most of those supporting therapies need more evidence to be used for standard wound care. Current study covers the use of sonicated Antlerogenic Stem Cells (ASC) extract on chronic wounds. METHODS: Study was performed on 20 dermatological patients with venous leg ulcers, divided into two groups - treated with and without ASC extract respectively. The area and circumference of the wounds during the follow-up visits were measured on the wound imprint. Dynamics of wound healing was determined and compared between control and study group; statistics includes changes in absolute values (wound area, circumference), as well as relative (percentage of wound decrease, circumference/area ratio) and their change in time. For the purpose of Ki-67 immunohistochemical staining, sections were sampled from the wound edge at distinct check-points during therapy. Results of both groups were compared with Student test or Mann-Whitney test, depending on results distribution. RESULTS: Besides Ki-67 expression, all tested wound healing parameters (including relative and absolute wound decrease and changes in circumference/area ratio) were statistically significant more favorable in experimental group. CONCLUSION: ASC extract significantly supported standard chronic wound treatment. Due to small population of study the results should be considered preliminary, yet promising for further research.

Experimental xenoimplantation of antlerogenic cells into mandibular bone lesions in rabbits: two-year follow-up.

Different types of cells require activation, and take part in annual, dynamic growth of deer antlers. Stem cells play the most important role in this process. This report shows the results of a two-year long observation of xenogenic implant of antlerogenic stem cells (cell line MIC-1). The cells were derived from growing antler of a deer (Cervus elaphus), seeded onto Spongostan and placed in postoperative lesions of mandibular bones of 15 experimental rabbits. The healing process observed in the implantation sites in all rabbits was normal, and no local inflammatory response was ever observed. Histological and immunohistochemical evaluations were performed after 1, 2, 6, 12 and 24 months, and confirmed the participation of xenogenic cells in the regeneration processes, as well as a lack of rejection of the implants. The deficiencies in the bones were replaced by newly formed, thick fibrous bone tissue that underwent mineralization and was later remodelled into lamellar bone. The results of the experiment with rabbits allow us to believe that antlerogenic cells could be used in reconstruction of bone tissues in other species as well.

Influence of antlerogenic stem cells on the healing of lesions in the corneal epithelium and corneal stroma in rabbits.

The aim of the study was to compare the effects of corneal healing in case of application of stem cells in various forms, in relation to the antibiotic-assisted procedures. Rabbits were divided into 4 groups in the first stage of the experiment. Group 0 (negative control group) was not subjected to any actions, which would cause damage to the cornea. The remaining three groups had their cornea damaged. Group 1 (positive control group) - no drugs were administered during the experiment. Rabbits in group 2 were administered with ointment containing stem cells to the lesion, while group 3 - with ofloxacinum. The stem cells were administered during the first five days, twice a day, onto the corneal surface. The further course of the experiment consisted of observing the rate of healing of the injured cornea and assessment of its transparency, size of lesion, hyperaemia, eyelid spasm and outflow from the conjunctival sac after 5, 10 and 20 days.In the second stage the animals were euthanised after clinical examination on the twentieth day of the experiment, in order to analyse the corneal reparative processes on the same day. The studies revealed that the application of antlerogenic stem cells had a positive effect on the healing process of corneal defects. The application thereof not only shortened the healing time, but also weakened or arrested the development of side effects. The results have demonstrated that the epithelial proliferation in each group was different. The longest was maintained in the group with stem cells, the shortest - in the group with chemotherapeutics. The use of antlerogenic stem cells had a positive effect on the healing process of corneal lesions. The use of stem cells helped to maintain high transparency of the cornea.