Early life stress is associated with anxiety, increased stress responsivity and preference for “comfort foods” in adult female rats

Figures & data

Figure 1. Body weight, at 13 weeks of follow-up after weaning, in control (n = 10) and ELS females (n = 20). Data are expressed as mean ± SEM. Repeated measures ANOVA showed an interaction between time and group (p < 0.0001), isolated effects of time (p < 0.0001) and group (p = 0.001).

Table 1. Comparison between the Control and ELS groups related to meal pattern.

Measure	Control (n = 8)	ELS (n = 19)	p Value	Adjusted p value
24-h intake (g)	18.42 ± 0.87	18.18 ± 0.55	0.819
Meal size (g)	17.37 ± 0.73	16.76 ± 0.43	0.464	0.644
Number of meals	9.51 ± 0.51	8.82 ± 0.38	0.329	0.227
Nocturnal intake (g)	14.13 ± 0.61	11.93 ± 0.40	0.007	0.038
Nocturnal meal size (g)	13.90 ± 0.64	12.04 ± 0.41	0.022	0.058
Number of nocturnal meals	6.91 ± 0.33	6.10 ± 0.39	0.223	0.168
Diurnal intake (g)	3.91 ± 0.56	5.78 ± 0.66	0.102	0.238
Diurnal meal size (g)	3.46 ± 0.58	4.72 ± 0.50	0.159	0.199
Number of diurnal meals	2.59 ± 0.35	2.72 ± 0.14	0.684	0.809

Meal pattern analysis using the BioDaq® system. Data are expressed as mean ± SEM. Student’s t-test demonstrated differences on the amount of nocturnal intake (p = 0.007) and nocturnal meal size (p = 0.022), without difference at the other meal patterns between the groups (p > 0.05). Adjusted p value refers to Univariate ANOVA considering body weight as a co-variable.

Figure 2. (A) Body weight during chronic exposure to the palatable diet. An effect of the neonatal group was detected (p = 0.0017), without interactions. (B) Regular diet intake during chronic exposure to the palatable diet. There was an interaction between dietary group and time (p = 0.008), as well as an effect of the neonatal group (p = 0.026) and the dietary group, as expected (p < 0.0001). Control (regular diet and 2 choices n = 5), ELS (regular diet and 2 choices n = 10). (C) Preference for the palatable diet during chronic exposure. There was an interaction between time and the neonatal group (p = 0.008), as well as isolated effects of the group (p = 0.006) and time (p = 0.016). Control group (n = 5) and ELS group (n = 9). Data are expressed as mean ± SEM.

Table 2. Preference test at BioDaq® system during 24 hours.

Groups	Mean	SEM	p Value	N
Control + regular diet	98.81^a	6.09	Ns	4
Control + 2 choices	74.09^b	4.09	<0.001	5
ELS + regular diet	92.55^a	3.80	Ns	9
ELS + 2 choices	98.78^a	3.85	Ns	10

Preference testing using the BioDaq® system. Data are expressed as mean ± SEM. Two-way ANOVA followed by the Bonferroni correction demonstrated that ELS animals did not experience a decreased preference for comfort foods after chronic exposure. Different letters represent statistically different means.

Figure 3. HPA response to acute stress. The dark line on the x-axis represents time of exposure to restraint stress. Data are expressed as mean ± SEM. (A) Analysis of corticosterone secretion in control (n = 8) and ELS (n = 8) females revealed an interaction between time and group, indicating that ELS females increased secretion in response to stress (p = 0.02), and an isolated effect of time (p < 0.0001). (B) Analysis of ACTH secretion in the same samples had no group effect (p = 0.467) and no interaction between time and group (p = 0.282), only an isolated effect of time (p < 0.0001).