Royal jelly reduces depression-like behavior through possible effects on adrenal steroidogenesis in a murine model of unpredictable chronic mild stress

Figures & data

Figure 1. Changes in body weight during exposure to unpredictable chronic mild stress (UCMS).

Data represent the means ± standard error of the mean (SEM) (non-UCMS: n = 20, UCMS: n = 20, UCMS+RJ: n = 20). A significant decrease in body weight was found between UCMS-exposed and non-UCMS-exposed groups at the start of UCMS exposure on day 6.

Figure 2. Effect of Royal jelly (RJ) on unpredictable chronic mild stress (UCMS)-induced increases in immobility times in the tail suspension test.

The test was performed one day after completion of the 3-week UCMS exposure. Data represent the means ± standard error of the mean (SEM) (non-UCMS: n = 17, UCMS: n = 19, UCMS + RJ: n = 18). p < 0.05 UCMS vs. UCMS+RJ by Welch’s t-test, and as a reference, P = 0.094 UCMS vs. non-UCMS by Student’s t-test.

Figure 3. Effect of Royal jelly (RJ) on the HPA axis response to unpredictable chronic mild stress (UCMS) exposure.

(a) Expression level of Pomc mRNA in the pituitary gland were expressed relative to the mean value of the non-UCMS group. Data represent the means ± standard error of the mean (SEM) (non-UCMS: n = 10, UCMS: n = 9, UCMS + RJ: n = 10). As a reference, p < 0.01 UCMS vs. non-UCMS by Student’s t-test.(b) Serum corticosterone level were expressed relative to the mean value of the non-UCMS group. Data represent the means ± SEM (non-UCMS: n = 20, UCMS: n = 20, UCMS + RJ: n = 20). P = 0.370 UCMS vs. UCMS+RJ by Student’s t-test, and as a reference, p = 0.077 UCMS vs. non-UCMS by Student’s t-test.

Table 1. Gene Ontology (GO) functional category of genes differentially expressed in the adrenal gland following exposure to unpredictable chronic mild stress (UCMS).

Term	Count	p-value
Cholesterol biosynthetic process	9	2.3 × 10^−7
Sterol biosynthetic process	8	1.0 × 10^−6
Isoprenoid biosynthetic process	6	1.9 × 10^−5
Steroid biosynthetic process	9	4.2 × 10^−5
Face morphogenesis	7	1.7 × 10^−4

Table shows the top 5 terms of the functional categories in the order of p values.

Figure 4. Changes in gene expression related to cholesterol metabolism in the adrenal grand.

Expression level of StarD4 mRNA (a) and Fdft1 mRNA (b) were expressed relative to the mean value of the non-UCMS group. Data represent the means ± standard error of the mean (SEM) (n = 10). The level of mRNA expression was normalized to that of the housekeeping gene β-actin. (a) p < 0.05 UCMS vs. UCMS+RJ by Student’s t-test; (b) p = 0.070 UCMS vs. UCMS+RJ by Student’s t-test, and as a reference, p = 0.078 UCMS vs. non-UCMS by Student’s t-test.

Figure 5. Effects of ethanol extract of Royal jelly (RJ) (EERJ) on unpredictable chronic mild stress (UCMS)-induced increases in immobility time in the tail suspension test.

The test was performed one day after completion of the 3-week UCMS exposure. Data represent the means ± standard error of the mean (SEM) (non-UCMS: n = 17, UCMS: n = 19, UCMS + EERJ: n = 17). p < 0.05 vs. UCMS UCMS+EERJ by Student’s t-test, and as a reference, p = 0.15 UCMS vs. non-UCMS by Student’s t-test.