ObjectiveWe aimed to study the protective effect of total glucosides of paeony (TGP) on chemical liver injury with pattern of liver yin deficiency in rats and determine whether it exerts these effects through the phosphoinositide 3-kinase(PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway.MethodsForty male Sprague-Dawley rats were randomly divided into the following four groups: (i) the blank group, (ii) the model group, (iii) the Yiguan Jian group, and (iv) the TGP group (10 rats per group). For 6 weeks, rats in all groups except for the blank group were injected intraperitoneally with 20% carbon tetrachloride olive oil solution and were given thyroid tablets (30 mg/kg) by gavage in order to establish the model of chemical liver injury with pattern of liver yin deficiency. During the modeling period, rats in the blank and model groups were gavaged daily with distilled water, while rats in the Yiguan Jian group and the TGP group were gavaged with 635 mg/kg of Yiguan Jian decoction and 50 mg/kg of TGP suspension, respectively. During the administration period, the body weight and rectal temperature of rats were measured every 2 weeks. After the administration, 24-hour food intake, 24-hour water intake, and moisture capacity in tongue surface were recorded. Serum cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), and interleukin-1 receptor antagonist (IL-1Ra) contents were measured by ELISA and the cAMP/cGMP ratio was calculated. Changes in the serum levels of alanine aminotransferase (ALT), alanine transaminase (AST), gamma-glutamyl transpeptidase (γ-GT), alkaline phosphatase (ALP), total bilirubin (TBIL), and total bile acids (TBA) were detected using colorimetric method. Masson staining was performed to observe the degree of liver fibrosis and to calculate the relative collagen area. Real-time PCR and Western blotting were conducted to determine the PI3K, AKT, and mTOR mRNA and protein expression levels in rat liver.ResultsCompared with the blank group, rats in the model group had a lower body weight at weeks 2, 4, and 6, a higher rectal temperature at weeks 2, 4, and 6, and a higher 24-hour food intake; the cAMP level was elevated, the cGMP level was decreased, and the cAMP/cGMP ratio was elevated; the contents of IL-1, IL-6, and TNF-α were elevated, and the contents of IL-10 and IL-1Ra were decreased; ALT, AST, γ-GT, ALP, TBIL, and TBA levels were elevated; the percentage of collagen area in the liver was increased; and the mRNA and protein phosphorylation levels of PI3K, AKT, and mTOR were elevated ( P<0.05). Compared with the model group, rats in the TGP group showed a decrease in rectal temperature at weeks 2, 4, and 6, a decrease in 24-hour food intake and water intake, and an increase in the moisture capacity in tongue surface; rats in the Yiguan Jian and TGP groups showed a decrease in cAMP, an increase in cGMP, and a decrease in the cAMP/cGMP, the contents of IL-1, IL-6, and TNF-α were decreased and the content of IL-10 was increased, the percentage of collagen area in the liver was decreased; ALT, AST, γ-GT, ALP, and TBIL levels were decreased in the TGP group, and PI3K, AKT, and mTOR were downregulated at the mRNA and protein levels(P<0.05).ConclusionTGP has a good protective effect on chemical liver injury with pattern of liver yin deficiency in rats. TGP may regulate the balance of yin and yang by inhibiting the PI3K/AKT/mTOR pathway, reducing the secretion of pro-inflammatory cytokines, and increasing the release of anti-inflammatory cytokines.

total glucosides of paeony;chemical liver injury;pattern of liver yin deficiency;inflammatory factors;phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin pathway;rats