Nowadays, in Ukraine, widespread application of two main methods of correction of age-related skin changes has been found: tredlifting with polydioxanone and Aptos threads in various modifications. The verbal translation of the English word "thread lifting" means "thread tightening". However, the term "tredlifting" is not new and involves a non-invasive surgical lifting of the face using special threads with microspheres/cones/teeth. The described method is also well-known and recognized throughout the world. However, despite a significant number of non-invasive interventions of this type, the issue of the effectiveness of collagenogenesis as a leading and prognostically meaningful criterion for the quality of the provision of this range of services was not studied either in Ukraine or in the world as a whole: - not determined the intensity of regenerative-inflammatory changes in the skin when using different types of implants; - the effectiveness of collagenogenesis, its qualitative and quantitative composition in the structure of the connective tissue formed in the implantation zones and around the place of "injury" was not investigated; - duration of implant persistence (except for data specified by the manufacturer) as a significant criterion of efficiency and expediency of their use is not studied. The purpose of the work was to establish the qualitative and quantitative composition of collagen, which is formed at the place of introduction of resorbing and permanent implants on the basis of the study of pathomorphological changes in the skin. The tasks of the work concerned the study of morphological changes in the area of implantation of threads - the fact of collagen formation at various chronological stages; determination of qualitative composition of collagen formed in peri-implant zones; establishing the relationship between the type of implantation thread and the intensity of collagenogenesis; definition of the terms of degradation of investigated resorbing implants in the skin of the experimental rats; determination of the presence and qualitative composition of inflammatory infiltration in peri-implant sites. The object of the study was peri-implant skin zone of white rats. The subject of the study was pathomorphological changes (particularly, collagenogenesis) in the places where implants were introduced. The studies were conducted on 310 sexually mature white male rats of the Vistar line weighing 100-130 g. All animals were kept under vivarium of Danylo Halytsky Lviv National Medical University, experiments were conducted in accordance with the provisions of the European Convention for the Protection of Vertebrate Animals used in experimental and other scientific purposes (Strasbourg, 1986), Council of Europe Directive 86/609 / EEC (1986), Law of Ukraine No. 3445-IV "Protection of Animals from Cruel Treatment". Animals were withdrawn from the experiment by overdose of etheric anesthesia (exposure 5-7 minutes). During the work, the following research methods were used such as simulation of inflammatory and regenerative processes in the skin of white male rats at the introduction of suture material with subsequent histological, histochemical and immunohistochemical staining, photographing histological microphotographes. For statistical research, two basic parameters were chosen for each sign - the frequency with which the sign occurs in the group, and the intensity of manifestations of this trait. The frequency index of the sign was expressed as the percentage of animals in which the sign was detected, compared with the total number of animals in the group. The intensity index was reflected in the form M ± m, where M is the mean value of the sum of the pluses calculated only in the animals in which this indicator is available, m is the mean square error from M. To compare the validity of the difference between the groups in terms of the frequency of manifestations of the trait, Pearson Criteria ( 2, Pearson's chi-squared). In order to compare the reliability of the indicator of the intensity of manifestations of the features among the groups, U-criteria Man-Whitney was chosen. The level of reliability is set at p<0.05. For statistical analysis, the software InVivoStat v.3.0 and SofaStat v.1.4.6 were used. Libre Office Calc v.5.2.2.2 and Microsoft Office Excel 2007 spreadsheets were used to create the database, calculate the data obtained and graphically present the results. Experimental animals of a total of 310 individuals were divided into 5 groups of 60 individuals, depending on the type of implant. The rats of all groups (14, 30, 90, 180, 365 and 540 days) were divided into 6 subgroups of 10 individuals. All 10 rats of each subgroup were implanted with the same type of suture material. The Aptos implants were used for work, namely: Excellence Visage (EV), Nano Spring (NS), Aptos Spring (AS), Light Lift Thread (LLT) and Light Lift Spring (LLS). The examination of the normal skin and after introduction of implants of different structures and chemical composition was carried out using general histological, histochemical and immunohistochemical methods. It is shown positive effect on implant implantation on morphofunctional features of the skin. In dyslization of morphological changes in the perimplant zone, it was found that in all groups of experimental rats at different chronological stages formed collagen with different term of biodegradation and in different quantities. It has been established that depending on the use of different types of implantation thread (chemical composition and structure), collagenogenesis is stimulated unevenly. Thus, the experiment has shown that the intensity of collagen formation is largely influenced by the degree of tissue trauma associated with the relief and the shape of the thread, as well as the presence of polylactic acid. On the 540th day of the experiment, none of the resorbing threads degraded completely, which falls within the scope of information provided by the manufacturer about the time of degradation at least 365 days, and the feasibility of using these cosmetic threads in aesthetic dermatology for the purpose of prolonged lifting skin correction. Specificity of the structure of implant threads, namely the shape of the spring (NS, AS, LLS), as a provocative factor for long-term alteration, causes long-term inflammatory response in tissues (including 90th day of the experiment). When studying the qualitative composition of collagen, it was established that 1 type was formed in all groups of subjects, but in different quantity. After implantation of EV thread 100% collagen type I was formed. All other threads also stimulate the formation of collagen type I, but the ratio of it to collagen type 3 varies
