INFLUENCE OF MICRORNA MIR-101 ON THE STRUCTURAL AND FUNCTIONAL ORGANIZATION OF THE WAKE-SLEEP CYCLE UNDER AMYLOIDOSIS IN RATS

The effects of transnasal introduction of microRNA (miR-101) in liposomal form on the structural and functional organization of sleep were investigated under conditions of modeling Alzheimer's disease in rats of late adulthood. It is shown that in experimental amyloidosis, course administration of miR101 promotes a significant (22-fold) increase in the duration of the deep slow-wave phase and a two-fold increase in the production of paradoxical sleep that is accompanied by a normalization of the rhythmic organization of the wake-sleep cycle and reflects the positive direction of these effects on its qualitative characteristics, probably, due to the inhibitory effect on the synthesis of the precursor of β-amyloid peptides. The results obtained may indicate the prospects for further study of the therapeutic potential of miR-101.

REACTION OF THE LYMPHOID SPLENIC TISSUE IN WHITE MICE ON AMYLOIDOGENESIS

The reaction of lymphoid splenic tissue of mice on albumin model of systemic amyloidosis (case group, N = 5) was studied and compared to a similar indicator of intact mice (N = 5). Paraffin sections of the spleen, stained with hematoxylin and eosin and Congo red, were microscoped in a regredient LED white light on "Lumam-4" microscope. The absolute area of lymphatic follicles (LFs), their diameters and the area of amyloid lesion were measured on microphotos obtained with the help of video-eyepiece Levenhuk C800 NG 8M in LevenhukLite program. The obtained data were used for calculating the indicators: the relative areas of amyloid lesion (SrelA)), the red (SrelKB) and the white (SrelBP) pulp, the red/white pulp index, LFs' ovalityindex. The number of LFs was counted in the field of vision at magnification of 100. The obtained data were processed using the methods of descriptive and variative statistics and presented in the form of M±m, where M is the mean, m is the standard deviation. Differences of the means were determined using z test. The morphological pattern of the spleen in intact mice corresponded to the histological norm. The wet mass of the spleen in intact animals was 0.75±0.01 g, no signs of amyloidosis were found. In the case group, the wet mass of the spleen increased to 2.2±0.06 g (p=0.000), SrelA was 33.85± 3.39%. The average number of LFs in the field of vision did not change. The diameters by the large and small axes differed by 18% in intact animals and by 6.6% in experimental ones (p=0.000). Respectively, the area of LFs decreased by 11.2% and the ovality index increased by 10.3% (p = 0.0066) in experimental mice. SrelKB and SrelBPdid not change during the formation of amyloidosis. But the Red/White Pulp Index increased by 59.2% (p=0.008). Simulation of amyloidosis in experimental animals was accompanied by a significant increase in the area of the red pulp and by a reduction in the area of white pulp. Thus, the calculated relative morphometric indicators are more informative than the directly measured initial data; the wet mass of the spleen during experimental amyloidosis formation significantly increases; the lymphoid tissue of the spleen readily responds to amyloidogenesis by the change in the ratio of the red and white pulp, as well as by the change in the shape and the area of the lymph follicles.

Treatment of experimental amyloidosis with antirheumatic drugs

Background. Because at present there is no known specific effective therapy for secondary amyloidosis, the aim of this study was to determine whether antirheumatic drugs inhibit the development of experimental AA amyloidosis induced in C57BL/6 mice by casein and fibrin injections. Materials and methods. Monotherapy with sulfasalazine (SSL) and diclofenac (D) and a combined treatment with diclofenac and prednisolone (D/P) according to prophylactic and therapeutic treatment protocols were investigated. The drugs were administered through intragastric gavage 5 times a week for 5 or 4 weeks in the following doses: D – 1 mg/kg, P – 10 mg/kg, and SSL – 100 mg/kg. A histopathological examination of splenic, kidney and hepatic tissues of mice was performed. The amount of amyloid was assessed semi-quantitatively by polarizing microscopy after Congo red staining. Results. Our study indicated that no positive effect of the prophylactic treatment with D could be seen on amyloid deposition in the target organs. Prophylactic combined treatment with D/P resulted in a significant improvement of disease symptoms and markedly reduced amyloid deposits in the spleen, kidneys and liver (p < 0.02–0.001). SSL therapy alone was more successful in the prophylactic treatment of experimental amyloidosis: the decrease of amyloid deposits was statistically significant in all examined organs (p < 0.04–0.001), and the suppression of amyloid formation was most significant in the kidneys and liver (p < 0.004–0.001). In the therapeutic treatment of experimental amyloidosis, combined treatment with D/P showed the most pronounced inhibition of amyloid formation in the internal organs (p < 0.006–0.001). The suppression (by 86.7%; p < 0.001) of amyloid deposits was most notable in the liver. Treatment of mice with D alone produced a significant reduction in amyloid deposition only in the liver (p < 0.03) and with SSL only in the spleen (p < 0.03). Conclusions. These findings suggest that D/P and SSL at relevant doses suppress amyloidogenesis, and this suppression is possibly related to the anti-inflammatory effect of antirheumatic drugs. Although these drugs cannot completely inhibit the disease in this model, a possibility remains that they may be clinically useful in rheumatic diseases associated with the formation of amyloidogenic derivatives. Keywords: mice, experimental AA amyloidosis, antirheumatic drugs