Antidepressant effects of the extract YZ-50 from Polygala tenuifolia in chronic mild stress treated rats and its possible mechanisms

Figures & data

Figure 1.  Effects of YZ-50 on the body weight gain of chronic mild stressed rats (mean ± SD, n = 12). Chronic treatment with YZ-50 (140 and 280 mg/kg) was given during 3 weeks chronic mild stress procedure. Effects of YZ-50 on the body weight gain of CMS stressed rats (mean ± SD, n = 12).

Figure 2.  Effects of YZ-50 on the sucrose consumption of rats exposed to chronic mild stress (mean ± SD, n = 12). Chronic treatment with YZ-50 (140 or 280 mg/kg) was given during 28 days of chronic mild stress procedure. Data are expressed as means ± SD (n = 12). ^##P <0.01 compared with unstressed control group; *P <0.05, **P <0.01 compared with vehicle + CMS group.

Figure 3.  Effects of YZ-50 on open field behavior during the 28-day study period in the chronic mild stressed rats. (A) The number of crossings during the test session and (B) the times of rearing during the test session. Chronic treatment with YZ-50 (140 and 280 mg/kg) was given during 28 days chronic mild stress procedure. Data are expressed as means ± SD (n = 12). ^##P <0.01 compared with unstressed control group; *P <0.05, **P <0.01 compared with vehicle + CMS group.

Table 1.  Effects of YZ-50 on the plasma and tissue corticosterone (CORT) or adrenocorticotrophic hormone level (ACTH) of chronic mild stress (CMS) rats (mean ± S.D., n = 12).

Groups	In plasma		In tissues
			Adrenal gland	Pituitary area
	CORT (ng/mL)	ACTH (pg/mL)	CORT (ng/mL)	ACTH (pg/mL)
Unstressed control	156 ± 10.51	23.62 ± 7.85	206.53 ± 12.27	104.86 ± 4.33
CMS+vehicle	170 ± 9.86^##	34.73 ± 4.75^##	217.5 ± 13.11^#	109.51 ± 2.75^#
CMS+desipramine	157 ± 10.53**	25.5 ± 4.26**	209.5 ± 8.12*	101.21 ± 5.75*
CMS+YZ-50 140mg/kg	161 ± 8*	28.86 ± 7.09*	206 ± 14.96*	90.02 ± 13.02**
CMS+YZ-50 280mg/kg	159 ± 11.25**	29.95 ± 4.44*	202.3 ± 12.11**	87.96 ± 15.95**

Chronic treatment with YZ-50 (140 and 280 mg/kg) was given during 28 days of CMS procedure. The animals were sacrificed at the end of procedure. The blood and tissue samples of rats were collected, and corticosterone and adrenocorticotrophic hormone levels were measured by radioimmunoassay. ^#P <0.05, ^##P <0.01 compared with un-stressed control group; *P <0.05, **P <0.01 compared with CMS + vehicle group.

Figure 4.  Effects of YZ-50 on BDNF level of hippocampus of chronic mild stressed rats. Chronic treatment with YZ-50 (140 or 280 mg/kg) was given during 28 days chronic mild stress procedure. Data are expressed as means ± SD (n = 7). ^##P <0.01 compared with unstressed control group; *P <0.05, **P <0.01 compared with vehicle + CMS group.