Disorder of intestinal amino acid pathway in depression-like offspring rats induced by maternal separation.

To investigate the intestinal amino acids pathway in depression-like offspring rats induced by maternal separation. Sprague-Dawley (SD) female rats were randomly divided into a control group (=8) and a maternal separation group (=8). After normal delivery, the maternal rats were separated from offsprings for 14 consecutive days and 3 h per day in maternal separation group; while rats in the control group was received no interventions in postpartum. Depression-like behaviors of offspring rats were evaluated using the sucrose preference test, novelty suppressed feeding test, and forced swimming test. Amino acid analyzer was used to detect the changes of amino acid contents in the small intestine, and the expressions of alanine-serine-cysteine transporter 2 (ASCT2), solute carrier superfamily 6 member 19 (BAT1) and L-type amino acid transporter 1(LAT1) were detected by Western blot. The weight of the offspring rats in the maternal separation group was significantly lower than that of the control group at 21 and 28 d (=4.925 and 5.766, all <0.01). Compared with the control group, the percentage of sucrose preference of the offspring rats in the maternal separation group was significantly reduced (=2.709, <0.05), and the feeding latency was significantly prolonged (=-13.431, <0.01). The immobility time in FST of maternal separation group was significantly longer (=-3.616, <0.01).Increased concentration of aspartic acid (=-6.672, <0.01) and down-regulation of glutamine (=3.107, <0.01) and glycine (=9.781, <0.01) were observed in maternal separation group. Western blot analysis revealed that the protein expressions of ASCT2 (=6.734, <0.01) and BAT1 (=9.015, <0.01) in maternal separation group were reduced, while the expression of LAT1 was increased (=-8.942, <0.01). Maternal separation can induce the depression-like behavior in offspring rats; the amino acid contents and the amino acid transporter expression in the small intestine are reduced, which may be related to depression-like behavior induced by maternal separation.