| Glycyrrhetinic acid belongs to terpenoid, which with the chemical structure of pentacyclic triterpene. The compound is extracted from leguminous plant liquorice, liquorice is an important traditional Chinese medicine, in the book of Treatise on Febrile Diseases’, there are110prescriptions, therein,74prescriptions contain liquorice, liquorice is widely used in clinical treatment. In recent years, with the development and perfection of pharmacology and experimental methods, licorice is found to have obvious anti-inflammatory and antiulcer function, moreover, it also has a function of anti-allergic reaction.At present, researches show that functions of licorice are mainly attributed to two reasons, the first one, an effective active substance glycyrrhizin exists in roots and stems of licorice, the second one, its final intracorporal metabolites contain effective active substance Glycyrrhetinic acid and its derivatives. Therefore, studies of liquorice and its main components arouse scholars’ study enthusiasm, in-depth research of effective components is to the benefit of seraching new drugs with high efficiency and low toxicity, so the study has great pharmaceutical value and practical significance.Allergic rhinitis is a type I allergic reaction, which is mediated by IgE, and it is a common and frequently encountered disease in E.N.T department and department of Head and Neck Surgery. In recent years, with the improvement of degree of industrialization, change of modern lifestyle and rapid deterioration of human ecological environment, morbidity of AR increases continuously, the disease significantly affects living quality of patients. The disease has become a global problem which affects human health. TJs exist widely between endothelial cells and epithelial cells of vertebrate bodies, they can seal intercellular space. TJs are located at the top of the cell, they exist around the cells with the shape of hoop, they can regulate cell proliferation, polarization and intercellular substance diffusion. Different epithelial tissues have different physiological functions, compositions and characteristics of intercellular TJs are different, in recent years, researches show that TJs participate in secretion of respiratory epithelial cells (Coyne et al.2002), barrier function of intestinal epithelial cells (Irvine et al.2000), reabsorption of renal tubular epithelial cells (Lee et al.2011) and other processes. Transmission electron microscopy (TEM) is an effective measure to observe TJs. In this paper, effect of long-term oral Glycyrrhetinic acid on blood lipid of rats was studied, meanwhile, a model of allergic rhinitis of rats was established, Glycyrrhetinic acid with low, middle and high dose was respectively given, and loratadine was used for intervention, during the study process of allergic rhinitis, effect of Glycyrrhetinic acid on TJs of nasal mucosa epithelial cells was studied, these can provide certain experiment basis for clinical treatment of Glycyrrhetinic acid and allergic rhinitis.Part one:The effect of18β-glycyrrhetinic acid on tight junctions of the nasal mucosa epithelial cells in rat models with allergic rhinitisObjective.-To observe18(3-glycyrrhetinic acid (GA) impact on ultrastructure of tight junctions (TJs) of nasal mucosa epithelial cells in rats models of allergic rhinitis (AR)Materials and Methods:6Wistar rats were randomly divided into control group, model group, loratadine group, and18β-glycyrrhetinic acid group, and each group had24rats. Ovalbumin was used to establish a rat AR model. The behavioral changes and the tight junctions of nasal epithelial were observed and compared in different groups after2,4,6and10weeks intervention.Results:The length of TJs in Allergic rhinitis model became shorter, Electron-high-density plasma membrane became thicker, number of the integration loci reduced and gap of TJs widened or even ruptured. With the consistent effect of allergens, the changes of TJs in the model group aggravated gradually, and the changes of ultrastructure of TJs in18β-glycyrrhetinic acid group was relieved apparently compared to model group and even were close to the control model with time.Conclusion:18β-glycyrrhetinic acid can recover the ultrastructure of the tight junctions of AR rat nasal epithelial cells.Part two:The effect of long-term18β-glycyrrhetinic acid on the blood glucose and blood lipids of rats Objective:To investigate the effect of long-term and different dose of18β-glycyrrhetinic acid on the triglyceride, total cholesterol and blood glucose of rats.Materials and Methods:The120Wistar rats were randomly divided into a blank group of30rats and a low (25mg/Kg), medium (50mg/Kg) and high (100mg/Kg) dosage groups of30rats. At the6th,14th,22nd,30th weeks and after4-week drug withdrawal, after the18β-glycyrrhetinic acid gavage, blood collection from cardiac puncture and blood glucose, triglyceride and total cholesterol were measured.Results:At the6th,14th,22nd,30th weeks and after4-week drug withdrawal, it had a lower tendency for blood glucose of rats, but it showed a no significant difference of the blood glucose among the rats in the low, medium and high dosage groups and the blank group (p＞0.05).And after the18β-glycyrrhetinic acid gavage, at the6th,14th,22nd,30th weeks and after4-week drug withdrawal, there was no significant difference among the rats in the low, medium, high dosage group and the blank group (p＞0.05)Conclusion:The long-term and different dose of18β-glycyrrhetinic acid had a decreasing tendency for blood glucose of rats, but it had no statistical significance. Interestingly, we found there were no influence on the triglyceride and total cholesterol of the rats in long-term GA. |
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