STRUCTURAL PECULIARITIES OF ARTICULAR CARTILAGE REACTIVE CHANGES IN RATS WITH AN EXPERIMENTAL UNDIFFERENTIATED DYSPLASIA OF CONNECTIVE TISSUE

In spite of all clinical manifestation of undifferentiated dysplasia of connective tissue (UDCT) including joint hypermobility syndrome still there are no exact morphological characteristics of structural articular cartilage changes on the background of UDCT.

THE AIM

to determine the structural peculiarities of articular cartilage reactive changes in rats with an experimental undifferentiated dysplasia of connective tissue.

STUDY DESIGN

animal experience.

METHODS

The object of the study was 162 knee joints of white laboratory rats, which were divided into 3 groups: - The 1st one - intact animals; the 2nd group consisted of experimental animals, each of which at the 18th day of fetal development was injected by 0.05 ml of antigen in 0.9% NaCl; the 3rd group consisted of control rats, injected by 0.05 ml of 0.9% NaCl at the 18th day of dated pregnancy. Morphological structure of articular cartilage of knee joints was examined at days 1st, 11th, 14th, 21st, 30th, 45th, 60th, 90th, 120th after birth. Fixation of histological material was carried out in 10% neutral formaldehyde. Histochemical, histological methods, statistic methods were used in the work.

RESULTS

Experiencing aggressive exposure from osteoblasts of the subchondral bone, along with increasing mechanical stress, the articular cartilage of rats with experimental UDCT, first compensatory turns thicker, and then irreversibly thin down, which is a prerequisite for the development of primary osteoarthrosis.

CONCLUSIONS

In rats with experimental UDCT the articular cartilage is isolated on the 11th day during the formation of the subchondral bone, in contrast to control rats in which articular cartilage differentiates on the 14th day after birth. In rats with experimental UDCT, the content of sulfated glycosaminoglycans in the matrix of the articular cartilage decreases. There is an accelerated replacement of the deep zone of the articular cartilage by the subchondral bone and the thinning of the articular cartilage on the 90th day after birth.

GENERAL MORPHOLOGICAL CHARACTERISTICS OF GASTRO-INTESTINAL TRACT OF RATS WITH EXPERIMENTAL UNDIFFERENTIATED DYSPLASIA OF CONNECTIVE TISSUE

The main purpose of the study is to determine peculiar morphological characteristics of structural changes of alimentary system organs in the case of experimental undifferentiated dysplasia of connective tissue (UDCT). Intranatal antigen introduction was conducted as an experimental model of UDCT. Objects of investigation - pharynx, duodenum, ileum, caecum, ascendant colon of white rats from the first up to the 60th day of postnatal life. Animals were contained in standard conditions of vivarium according to Law of Ukraine № 1759-VI (15.12.2009) On the Protection of Animals from Cruelty. Morphological structure of organs were examined at days 1st, 7th, 14th, 21th, 45th, 60th after birth. Morphometric, histological, histochemical, lectinistochemical, immunehistochemic and statistic methods were used. Analysis of the obtained results was conducted by means of statistical methods with the use of computer license program «Statistica for Windows 13» (StatSoft Inc., № JPZ804I382130ARCN10-J). The compared results considered such, that for certain differ at р<0,05 that is generally accepted for biological and medical researches. On the background of experimental syndrome of UDCT, developed by intranatal antigen loading, it is settled that the number of intraepithelial lymphocytes, number of lymphocytes of submucose layer of alimentary tract increases. Ratio between cells of mucosa (including epithelial layer and submucosal layer) changes. Interrelation between layers of alimentary tube changes resulting in the thickening of mucosa (including epithelial layer and submucosal layer) and thinning of muscular layer. These inflections result in elongation of duodenum, small and large intestines. Throughout the first month after birth in rats with experimental syndrome of UDCT lymphocyte/epitheliocyte, lymphocyte/ fibroblast and lymphocyte/mitosis indexes change in proximal and distal parts of digestive tract.