Age- and sex-related dynamics of structural and functional motor behavior interactions in striatum neurons in rats

Aim. To study the age-related dynamics of structural and functional interactions of striatal neurons in the implementation of acts of motor behaviour in rats of both sexes.

Materials and methods. The study was carried out on 36 Wistar rats of both sexes aged 2, 7 and 16 months (n = 6 per group). In animals of all groups, locomotor activity was determined using a Laboras device (Metris, the Netherlands) for

15 minutes, after which the brain was sampled to determine the number and size of neurons in the striatum. The median and interquartile range of the index of motor activity and the number of neurons were determined, and to study the relationship between these indicators, a correlation and regression analysis was performed with the construction of linear and polynomial trends, and the coefficient of determination R2 was calculated.

Results. The size of neurons did not change significantly with age in the rats of both sexes. The number of neurons differed statistically in the rats of different sexes in all age groups. In male rats, the maximum number of neurons was noted at the age of 7 months with a decrease to 16 months. In female rats, the maximum number of neurons was recorded at the age of 2 months with a further decrease to 7 and 16 months. According to the regression analysis, a linear strong relationship (R2 =

0.80 for males, R2 = 0.79 for females) was established between the number of neurons in the striatum and motor activity in 2-month-old animals. At the age of 7 and 16 months the relationship is non-linear.

Conclusion. The number of neurons in the striatum is subject to sex and age dynamics, while their size remains unchanged from 2 to 16 months. For animals of both sexes, a decrease in the role of the striatum in providing motor activity in the process of growing up was noted. This relationship reaches its maximum in 2-month-old rats and then decreases.

Treatment of chronic liver disease using cell‑engineered constructs: morphofunctional characteristics

Objective: to study the effectiveness of correcting the morphofunctional characteristics of the liver in an experimental model of chronic liver disease (CLD), using implanted cell-engineered constructs (CECs).

Materials and methods. Experiments were carried out on male Wistar rats (n = 80) aged 6–8 months with an initial weight of 230–250 g. CLD was modeled by inoculating the rats with 60% CCl4 oil solution for 42 days based on a modified scheme. Microgel based on recombinant spidroin rS1/9 was used as a matrix for CECs fabrication. Allogeneic liver cells (LCs) and multipotent bone marrow-derived mesenchymal stem cells (BM-MSCs) from a healthy donor were used as the cellular component of the CECs. The effectiveness of the corrective effect of the implanted CECs was assessed in an experimental CLD model (n = 60) in two groups of rats: Group 1 (control, n = 20, 1 mL of saline solution was injected into the damaged liver parenchyma) and Group 2 (experimental, n = 40, CECs containing allogenic LCs and BM-MSCs in a 5 : 1 ratio in a volume of 1 mL were implanted into the damaged liver parenchyma). For long-term monitoring of the CEC state, the CECs were labeled by additional inclusion in Cytodex-3. The effectiveness of the regulatory effect of CECs on regenerative processes in the liver was evaluated using biochemical, morphological and morphometric techniques, as well as by flow cytometry at 90 days after implantation.

Results. In the control group, the mortality rate in CLD was 25%. There was no death in the experimental group with CLD after CEC implantation. The CECs were found to have a corrective effect on the biochemical and morphological parameters of the liver in CLD during 90 days of follow-up, with concomitant preservation of structural cellular homeostasis in the implanted CECs. Conclusion. Implantation of CECs in the liver facilitates effective correction of CLD by activating regenerative processes in the damaged liver, which is due to long-term preservation of structural cellular homeostasis in the CECs.

Effect of Skin Application of Dorogov's Antiseptic-Stimulant on Behavioral Reactions in Rats

Local application of the Dorogov's antiseptic-stimulant onto the skin of 2-month-old male Sprague-Dawley rats in a low dose (0.5 g/kg/day) for 1 week increased motor and ultrasonic activity of experimental animals and the content of activated c-Fos⁺ neurons on the cingular, motor, insular, and pyriform cortex and in the striatum.

[CHANGES IN THE NUMBER OF NEURONS IN THE MOTOR CORTEX OF RATS AND THEIR LOCOMOTOR ACTIVITY IN THE AGE ASPECT]

Using Laboras hardware-software complex, which is a system of automatic registration of behavioral reactions, the locomotor activity 1-, 8- and 16-month-old male rats (12 animals in each group) was recorded followed by counting the number of neuron cell bodies of in the layer V of the motor cortex in Nissl stained slides. It was found that the number of neurons in the motor cortex varied in different age groups. Maximal number of neurons was observed in 8-month-old animals. Motor activity was found to correlate with the number of neurons.