Evaluation of tentative and research activity in rats with experimental allergic encephalomyelitis against the administration of cell-free cryopreserved biological agents
Authors: Hladkykh F.V. 
Published: September 2024

Background. Today, 20,924 people with a diagnosis of multiple sclerosis (MS) live in Ukraine. Experimental allergic encephalomyelitis (AEM) is a classical model of MS in laboratory animals. As a new strategy for the treatment of MS, our attention was drawn to the use of modern biotechnological means that do not contain cells – placenta cryoextract (CEP), spleen cryoextract (CES) and conditioned medium of mesenchymal stem cells (MSC-CM). Purpose – to characterize the tentative research activity of rats with experimental allergic encephalomyelitis against the background of the introduction of cell-free cryopreserved biological agents (CEP, CES and MSK-CM). Materials and Methods. The study was conducted on 42 non-linear laboratory male rats weighing 200–220 g. AEM was modeled by injecting rats with an encephalitogenic emulsion subcutaneously at the base of the tail at a dose of 1.0 ml/kg of body weight. Encephalitogenic emulsion for rats was prepared according to the method by O.O. Nefiodov and al. (2017). The emulsion consisted of Сomplete Freund’s Аdjuvant (CFA) and allogeneic brain homogenate in a 1:1 ratio. AEM treatment was carried out from the 12th to the 20th day of the experiment. CcEP, CES and MSC-CM were administered every other day intramuscularly (a total of 5 injections), on days 12, 14, 16, 18 and 20, respectively. The glucocorticoid methylprednisolone (MP) was used as a reference drug. Behavioral responses of animals were studied in the «open field» test. To study behavioral reactions, rats were placed in the center of a square platform one by one, and behavioral reactions were recorded for 3 minutes, which were calculated as the sum of episodes by activity type: motor activity (number of squares entered by the animal); exploratory activity (total number of rear-limb climbs and number of peeks and/or sniffs at «burrows»). Results. It was established that the introduction of an encephalitogenic emulsion from an allogeneic brain homogenate and CFA in a ratio of 1:1 led to pronounced disorders of orientation-research activity in rats on the 12th day of the experiment. The development of AEM in rats was accompanied by pronounced disorders of orientation and research activity. On the 12th day of the experiment, a statistically significant (p = 0.009) decrease in motor activity by 78.8% and a statistically significant (p ˂ 0.01) decrease in exploratory activity of rats with AEM by 78.0% relative to baseline values were observed. On the 21st day of the experiment, the rats of the control group with AEM without treatment showed a relative regression of disorders of orientational research activity, however, the studied indicators remained significantly lower than their initial values. The analysis of the recovery of motor activity on the 21st day of the experiment in rats with AEM showed that the most clearly indicated indicator increased against the background of five-time introduction of MSC-CM (р ˂ 0.01), and the least (p ˂ 0.01) motor activity was restored in rats, which was administered CES. A study of the research activity of rats with AEM showed that the introduction of the studied biological drugs led to the restoration of the indicated spectrum of activity in rats on the 21st day of the experiment. It was found that MSC-CM and CES exceeded the effectiveness of MP in terms of the ability to restore the research activity of rats with AEM, which may indicate not only their anti-inflammatory activity, but also a possible neuroprotective effect on the model of the studied autoimmune neurodegenerative disease. Conclusions. According to the ability to restore locomotor activity (% of changes in the indicator at 21 days compared to the indicator at 12 days) in AEM in rats, the investigated cell-free cryopreserved biological agents can be arranged in the following sequence: MSC-CM (368.6%) ˃ CEP (286.1%) ˃ CES (102.0%). According to the ability to restore research activity in rats with AEM on the 21st day of the experiment, the investigated cell-free cryopreserved biological agents can be placed in the following sequence (% changes in the indicator on the 21st day relative to the indicator on the 12th day): MSC-CM (347.1%; p ˂ 0, 01) ˃ CES (186.2; p ˂ 0.01) ˃ CEP (131.8%; p ˂ 0.01).