BACKGROUND:Since chronic liver disorders are associated with bone loss commonly,it is very significant to probe into the prevention of such bone loss for the treatment of osteoporosis. OBJECTIVE:To study the mechanism of glycyrrhizic acid on prevention and treatment of bone loss induced by liver fibrosis in mice. DESIGN:Randomized and controlled study in which the experimental animals were taken as the objects. SETTING:Experimental animal center,central experimental room and pharmacological research room of a university MATERIALS:The experiment was performed from January to September 2001.Forty common-grade PCR mice of either sex were employed,weighted varied from 20 to 22 g, provided by Experimental Animal Center of the Institution.According to mass-equivalence principle,4 groups were randomized,named as control,model group,the treatment with colchicine group(CL group) and the treatment of glycyrrhizic acid group(GA group) with 10 mice in each group. METHODS:Except the control group,in the model group,CL group and GA group,the subcutaneous injection with 400 g/L carbon tetrachloride prepared with peanut oil was given for 5 weeks to induce liver fibrosis in mice.Afterward,the treatment was applied with carbon-tetrachloride peanut-oil solution 10 mL/kg,colchicum autumnale solution 0.1 g/kg and glycyrrhizic acid solution 0.1 mg/kg successively.At the end of the experiment,the eyeball was extirpated for blood collection.The serum was separated to assay the various relevant biochemical indexes of liver injury,observe the changes in liver pathological tissues and measure bone calcium(Ca2+) content of femur and the contents of other bone trace elements as well as bone oxyproline hydroxyproline(Hyp). MAIN OUTCOME MEASURES:①Effects of glycyrrhizic acid on serum biochemical index after liver injury in mice of every group;②Effects of glycyrrhizic acid on pathological changes of liver in mice of every group;③Effects of glycyrrhizic acid on substance of bone in mice of every group;④Effects of glycyrrhizic acid on the contents of bone trace elements in mice of every group.
RESULTS:The levels of serum aspartate aminotransferase(AST) and alanine aminotransferase(ALT) in CL group and GA group were lower than those in the model group(P< 0.01).The level of albumin and ratio between albumin and globulin in the model group were lower than those in CL group and GA group(P< 0.01,P< 0.05).The content of bone calcium in CL group and GA group were lower than that in the control group (P< 0.05),but that was higher than the model group(P< 0.05).The unit contents of copper(Cu2+), magnesium(Mg2+)and zinc(Zn2+)in the right femur of the model group were all higher than the control group (P< 0.01),but the contents of those in GA group were not indicated significant differences compared with the control group (P >0.05).The liver pathological changes of mice in GA group were obviously milder compared with the model group(P< 0.01) and it was shown with VG staining the severity of hyperplasia of liver collagenous fibers was remarkably milder compared with the model group(P< 0.01). CONCLUSION:The extractive solution of glycyrrhizic acid induces medical metabolic enzyme in the liver,enhances detoxification of liver,protects liver to maintain protein metabolic level and maintains the normal metabolism of bone to promote bone Ca2+and balance between oxyproline hydroxyproline(Hyp) and trace elements of bone so as to prevent and treat bone loss.