Maternal separation in early life impairs tumor immunity in adulthood in the F344 rat

Figures & data

Figure 1.  Mean weights ( ± SEM) (g) for animals in the ‘maternal separation’ (n = 30) and ‘control’ (n = 28) groups used for the assessment of corticosterone and NK cytotoxicity prior to chronic restraint stress and tumor cell treatment. Regression analysis of ‘neonatal treatment’ and ‘day of life’ on weight was significant (F[2,689] = 997.2, P < 0.001) whereby both factors made a significant contribution to weight (P < 0.05 in each case).

Figure 2.  Mean plasma concentration of corticosterone ( ± SEM) for ‘maternal separation’ versus ‘control’ groups across ‘restraint’ versus ‘non-restraint’ groups (n ≅ 8 per group) following chronic restraint stress (ANOVA: F[l,26] = 9.7, *P < 0.01). These are measures at the end of 6 days of repeated restraint and tumor cell treatment.

Figure 3.  Mean NK cell activity ( ± SEM) for all animals in the ‘maternal separation’ versus ‘control’ conditions across ‘restraint’ versus ‘non-restraint’ conditions, E:T ratio 4:1 for male rats (n ≅ 7 per group; ANOVA [F{1,23} = 6.3, P < 0.05]). Planned comparisons revealed that NK cytotoxicity was significantly higher in control rats subjected to neither maternal separation nor chronic restraint stress in adulthood compared with all other groups (*P < 0.05, for all).

Figure 4.  Mean number of lung metastases ( ± SEM) for ‘maternal separation’ versus ‘control’ conditions across ‘restraint’ versus ‘non-restraint’ conditions (n = 10 per group; ANOVA [F{1,32} = 11.7, P < 0.001]). Planned comparisons revealed that the rats subjected to both maternal separation and chronic restraint stress in adulthood demonstrated significantly more metastases compared with all other treatment conditions (*P < 0.05, for all).