Mast Cells Play A Role In The Regulation Of Sexual Preference In Male Mice

Abnormal sexual preference is generally present in many kinds of animals including human. However, its cell and molecular mechanism has been little explored. Recent studies have suggested that the decline of brain 5-hydroxytryptamine （5-HT） level could alter sexual preference of mice. Mast cells are immune cells and it has been shown that mast cells are correlated with sexual behavior. As we know,5-HT is one of important mediators released from mast cells. Thus, the effects of mast cell deficiency and reconstitution on sexual preference in mice were studied in this thesis.In this study, mast cell deficient mouse model KitW-sh/W-sh (Sash^-/-) and wild type mice （WT） were used and the results were as follows:1) Sash^-/- mouse showed significantly more male-male mounting behavior and its sexual preference was significantly different from WT.2) Ultrasound research indicated that male Sash^-/- mice emitted mating related ultrasound to both male and female mice indiscriminately while male WT preferred emitting this kind of ultrasound to female mice.3) In the mating choice assay, male Sash^-/- mice exhibited the same mating preferences to the male and female mice. Further, the results in the bedding preference assay and odor preference assay were similar.4) Intravenous injection of bone marrow cultured mast cells （BMMC） inhibited male-male mounting behavior of Sash^-/- mouse and its sexual preference was almost restored back to WT levels. In the mating choice assay, Sash^-/- mice with injected BMMC displayed normal mating preference, and the results in the bedding preference assay and odor preference assay supported the above outcomes.5) There was no significant difference in serum testosterone levels between Sash^-/- mice and WT, whereas a slight difference between serum estradiol concentrations of two groups. BMMC reconstitution had not changed testosterone and estradiol levels in serum of mice. Brain serotonin levels of mast cell-deficient mice were similar to WT.In summary, mast cells play a crucial role in the regulation of sexual preference in male mice and it is not likely that these immune cells regulate sexual preference through sex hormones or 5-HT.