[The protection mechanisms of glycine against liver injury induced by lipopolysaccharides].

OBJECTIVE: To explore the protective mechanisms of glycine (Gly) on lipopolysaccharides (LPS) induced liver injury.

METHODS: BABL/c mice were randomly divided into a LPS group, in which the animals were intraperitoneally injected with 10 mg/kg LPS, and a Gly group, in which the mice were pretreated with a 5% Gly-containing diet for 3 days before receiving the same dose of LPS. The livers of the mice were examined for histopathological changes. The TNF alpha and interleukin-10 (IL-10) levels in the blood plasma were measured using ELISA analysis. The mRNA expression of TNF alpha, IL-10 and Toll-like receptor 4 (TLR4) in hepatic tissues were detected using RT-PCR analysis. Protein expression of TLR4 in livers was detected using immunohistochemistry.

RESULTS: The Gly group mice had an improved survival rate and attenuated LPS-induced pathological changes in the liver tissues in comparison with those of the LPS group animals. The TNF alpha levels [(1,852.80+/-126.64) pg/ml vs (708.83+/-51.29) pg/ml, P<0.05] in plasma, as well as the expression of TNF alpha (A 1.59+/-0.14 vs. 0.91+/-0.11, P<0.05) and TLR4 (A 0.97+/-0.12 vs. 0.53+/-0.11, P<0.05) mRNA in liver tissues were decreased. However, the levels of plasma interleukin-10 [(344.09+/-31.70) pg/ml vs (418.64+/-38.86) pg/ml, P<0.05] were significantly increased and the peaking time left, shifted.

CONCLUSIONS: Gly pretreatment could attenuate LPS -induced liver injury in mice, which may be associated with its role in down-regulating TLR4 expression and up-regulating IL-10 production.