The state of cellular immunity link and steroid hormones in bitches under different conditions of the reproductive system

The purpose of the conducted study was to establish the correlation between indicators of the cellular immunity link and the concentration of steroid hormones in bitches under different conditions of the reproductive system. Seventeen crossbred bitches aged from 2 to 5 years were involved in the experiment. They were divided into three groups depending on the state of the reproductive system: anestrus, sexual cycle, and pyometra. The following immunophysiological indicators were determined in blood plasma: the absolute number of leukocytes, lymphocytes, and their immunoregulatory subpopulations, and the phagocytic activity of neutrophils. The content of progesterone, estradiol, and cortisol was determined in serum. According to the results of the research, it was established that the absolute number of neutrophils, as the most reactogenic cells of the innate link of cellular immunity, was 0.51 G/L higher in the group of animals with pyometra than in the group of animals during the sexual cycle, and by 0.84 G/L in bitches in conditions of anestrus. The absolute number of phagocytic active neutrophils in conditions of pyometra was 2.32 ± 0.58 G/L (Р < 0.001). However, as a percentage of the absolute number of neutrophils, this indicator was 66 %. During the sexual cycle, the absolute number of neutrophils capable of phagocytosis was 2.33 ± 0.51 G/L, which is 78 % of the absolute number of all neutrophilic leukocytes. The indicator of the absolute number of lymphocytes was reliably (P < 0.05) lower in the group of bitches with pyometra – 1.48 ± 0.35 G/L, which is 0.92 G/L less compared to the group of animals in the anestrous period. Analysis of the absolute number of monocytes showed that this indicator was the same in bitches during the pyometra and anestrous periods and was lower by 0,07 G/L during the sexual cycle. The absolute number of B-lymphocytes, as a humoral link of adaptive immunity, in bitches in conditions of the anestrous and estrous period was the same and amounted to 0.30 G/L. In the group of bitches with pyometra, a reliable decrease of this indicator by 33 % was established (Р < 0.05). The population of natural killer (NK) lymphocytes was also the lowest in bitches with pyometra, almost twice as compared to animals during the sexual cycle. Conducted research on determining the absolute quantitative indicators of the cellular immunity link showed their dependence on the functional state of the reproductive system. It was established that the absolute number of neutrophils in pyometra was higher than in animals in anestrus. However, at the same time, their relative number capable of phagocytosis was the lowest. In conditions of pyometra, the lowest number of lymphocytes and their main subpopulations were observed.