DOPAMINE AND NOREPINEPHRINE CONTENT IN THE CEREBRAL CORTEX OF BALB/C NUDE MICE WITH MULTIPLE PRIMARY MALIGNANT TUMOURS

Abstract

The increase in patients with multiple primary malignant tumors (MPMT) determines the need to study their pathogenesis. An important role in the functioning of brain neurons belongs to norepinephrine (NA) and dopamine (DA), which can contribute to tumor development in immunodeficient mice of both sexes.
 The purpose of our work was a comparative analysis of dopamine and norepinephrine content in the cerebral cortex of immunodeficient mice of both sexes during isolated and combined growth (MPMT model) of experimental tumors.
 Materials and Methods. 56 BALB/c Nude mice were divided into 7 groups: 4 groups of females (intact, mice with standard subcutaneous inoculation of B16/F10 melanoma or Lewis lung carcinoma (LLC), mice with MPMT model – subcutaneous injection of a tumor cell suspension); 3 groups of males (the same groups as for females, except LLC). ELISA technique was used to detect NA and DA content.
 Results. In the cerebral cortex of intact females, DA level was higher (3.7 times) and NA level was lower (1.8 times) when compared to males. In all types of tumor growth, monoamine level decrease was observed in animals of both sexes. In females, DA decrease was 57.2 % and 65.8 % with isolated B16/F10 melanoma growth and LLC, and with MPMT it reached 70 %. In males, DA decreased significantly only with MPMT – by 37.6 %. NA in females decreased in case of LLC and MPMT by 26.2 % and 28.1 %, respectively. In males, NA decreased with B16/F10 melanoma and MPMT by 53.3 % and 43 % respectively (p<0.0001 in all cases). In females, there was a more than twofold increase in the ratio of stress-implementing NA and stress-limiting DA (NA/DA) levels, while in males there was a decrease in this index. This was consistent with the large tumor sizes (2–3 times larger) in case of MPMT in females.
 Conclusion. The results indicate the participation of brain neurotransmitters in the development of multiple primary malignant tumors in BALB/c Nude mice of both sexes and lower stress resistance in females.