Effects And Mechanisms Of Total Glucosides Of Paeony On Experimental Chronic Eczema

Chronic eczema represents a pruritic chronic inflammatory skin disease, most consider it is a delayed type hypersensitivity (DTH) developing on skin, resulting from complicated interaction of genetic and environmental factors, but the certain course of this disease is still unknown. However, the pathogenesy, pathology and clinical manifestation are extremely similar with contact dermatitis. Multitudes of investigations suggest that disequilibrium of Th2/ Th1 play a key role in the elicitation phase of this disease,and much scientific effort has been invested in elucidating the roles of Th2/ Th1 cytokines involved in this disease.Over the last decade, chronic eczema has shown a rising prevalence together with allergic rhinitis and allergic asthma.Nowadays the main choice is local or whole-body treatment with H1 receptor antagonist, glucocorticosteroid, Chinese crude drug, and antiseptic drug. The above-mentioned drugs with quite obvious adverse effects are greatly limited in the treatment of chronic eczema. New safe and effective drugs for chronic eczema are urgently needed. Total glucosides of paeony (TGP) is a utility locus extracted from Chinese traditional herb paeoniae radix and has been approved to be manufactured and commercially sold as the first anti-inflammatory immunomodulating drug in China. It has been proved to be effective in treating inflammatory immunological diseases and can regulate well immune balance. Therefore, it has a favorable prospect in the treatment of immune diseases. For example, it acquires obvious therapeutical effect and safety for rheumatoid arthritis (RA). The pathological mechanism of chronic eczema may be also involved the disorder of immunologic function. This suggests that TGP may be effective for chronic eczema. In this experiment, we tried to find out whether TGP had therapeutical effect on chronic eczema by establishing the model of mice and guinea pig with chronic eczema.OBJECTIVETo clarify the effects and mechanisms of TGP on mice with chronic dermatitis- eczema and guinea pig with chronic eczema. In this experiment, we tried to find out whether TGP has therapeutical effects on mice with chronic dermatitis- eczema and guinea pig with chronic eczema by observation the effects of TGP on ear swelling, pathology and production of IL-2 and IL-4 in mice with chronic dermatitis- eczema and guinea pig with chronic eczema.METHODSThe model of mice with chronic dermatitis- eczema and guinea pig with chronic eczema was induced by dinitrochlorobenzene (DNCB). Micrometer caliper was used to measure the thickness of the middle part of the right ear and then used to calculate the different thickness of the right ear in the different periods of the experiment. Electric balance was used to measure the weight of ear slices and then used to calculate the difference in weight between the left and right ear. Light microscope was employed to record the pathologic change of the ear tissue. In addition, radioimmunoassay (RIA) was the method chosen to determine the content of serum IL-2 and IL-4.RESULTS1.Effects of TGP on swelling of ear in mice with chronic dermatitis- eczema and guinea pig with chronic eczema induced by DNCB1.1 Effects of TGP on swelling of ear in mice with chronic dermatitis- eczema induced by DNCBBefore induction (d0) and 24h after each stimulation (d5,d8,d11,d14),we measured middle thickness of the right ear by micrometer caliper, calculated swelling of the right ear in the different periods of the experiment. The ear of model group swelled significantly compared with normal group. In the treatment groups, drugs were given by gastric administration from d0 to d13, once a day for 14 days. The mice in normal and model group were fed the same volume of vehicle only. the groups treated with TGP (30,60 and 120 mgï¹’kg^-1 ) were able to reduce the swelling of the ears significantly.1.2 Effects of TGP on swelling of ear guinea pig with chronic eczema induced by DNCBBefore induction (d0) and 24h after each stimulation(d14,d21,d28,d35),we measured middle thickness of the right ear by micrometer caliper, calculated swelling of the right ear in the different periods of the experiment. The ear of model group swelled significantly compared with normal group. In the treatment groups, drugs were given by gastric administration from d21 to d34, once a day for 14 days. The guinea pigs in normal and model group were fed the same volume of vehicle only. the groups treated with TGP(42mg.kg^-1),TGP(84 mgï¹’kg^-1 ),TGP(42mg.kg^-1)+Pre(1.4 mg.kg^-1)were able to reduce the swelling of the ears significantly.2.Effects of TGP on ear weight of mice with chronic dermatitis- eczema and guinea pig with chronic eczema induced by DNCB2.1 Effects of TGP on ear weight of mice with chronic dermatitis- eczema induced by DNCB The animals were killed at 24 hours after the last stimulation(d14), used metallic perforex(diameter, 0.9cm)to stroke in the middle of ear, each tissue was weighted by electronic balance, calculated the difference in weight between the left and right ear.The swelling of right ear of model group were significant compared with normal group, the right ears were heavier than the left ears. The groups treated with TGP(120mgï¹’kg^-1) was able to reduce the swelling of the ears significantly.2.2 Effects of TGP on ear weight of guinea pig with chronic eczema induced by DNCBThe animals were killed at 24 hours after the last stimulation(d35), used metallic perforex(diameter, 0.9cm)to stroke in the middle of ear, weighting each tissue weight by electronic balance, calculated the difference in weight between the left and right ear.The swelling of right ear of model group were significant compared with normal group, the right ears were heavier than the left ears. The groups treated with TGP(84 mgï¹’kg^-1 ),TGP(42mg.kg^-1)+Pre(1.4 mg.kg^-1)were able to reduce the swelling of the ears significantly.3.Effects of TGP on ear pathology in mice with chronic dermatitis- eczema and guinea pig with chronic eczema induced by DNCB3.1 Effects of TGP on ear pathology in mice with chronic dermatitis- eczema induced by DNCBParaffin block was cut into slices and dyed with the HE, then the infiltration of inflammatory cells was observed under light microscope.Compared with normal group, the ear epidermis of the model was in excessive keratinization and thick, the ear dermis were infiltrated by lots of monocytes and the vascellum expanded seriously, the groups treated with TGP(30,60 and 120 mgï¹’kg^-1) were able to improve the ear pathologic change, reduce infiltrated monocytes and relieve inflammatory reaction effectively.3.2 Effects of TGP on ear pathology in mice with chronic dermatitis- eczema induced by DNCB Paraffin block was cut into slices and dyed with the HE, then the infiltration of inflammatory cells was observed under light microscope.Compared with normal group, the ear epidermis of the model was in excessive keratinization and thick, the ear dermis were infiltrated by lots of monocytes and the vascellum expanded seriously, the groups treated with TGP(21mg.kg^-1,42mg.kg^-1 and 84mg.kg^-1),TGP(42mg.kg^-1)+Pre(1.4 mg.kg^-1)were able to improve the ear pathologic change, reduce infiltrated monocytes and relieve inflammatory reaction effectively.4.Effects of TGP on IL-2 and IL-4 production in mice with chronic dermatitis- eczema and guinea pig with chronic eczema induced by DNCB4.1 Effects of TGP on IL-2 and IL-4 production in mice with chronic dermatitis- eczema and guinea pig with chronic eczema induced by DNCBMice in model group had a low serum level of IL-2 and a elevated serum level of IL-4 compared with normal group, the groups treated with TGP(30,60 and 120 mgï¹’kg^-1) were able to elevate the serum level of IL-2 and lower the serum level of IL-4.4.1 Effects of TGP on IL-2 and IL-4 production in mice with chronic dermatitis- eczema and guinea pig with chronic eczema induced by DNCBGuinea pig in model group had a low serum level of IL-2 and a elevated serum level of IL-4 compared with normal group, the groups treated with TGP(42,84 mgï¹’kg^-1 ),TGP(42mg.kg^-1)+Pre(1.4 mg.kg^-1)were able to elevate the serum level of IL-2 and lower the serum level of IL-4.5. Combination of TGP and Pre was able to reduce the dosage of Pre and enhanced the therapeutic action of Pre induced by DNCB In the guinea pigs experiment, we adopted the combination of TGP(42mg.kg^-1)and Pre(1.4 mg.kg^-1) to observe whether TGP was able to reduce the dosage of Pre on the same therapeutic efficacy.Results manifested that combination of TGP(42mg.kg^-1) and Pre (1.4 mg.kg^-1)was significantly different compared with TGP(42mg.kg^-1)and Pre(1.4 mg.kg^-1), but as similar as Pre(2.8mg.kg^-1). CONCLUSIONS1. TGP has therapeutic effects on mice with chronic dermatitis- eczema and guinea pig with chronic eczema.2. Mechanisms of effects of TGP on chronic eczema are possibly concerned with that TGP can regulate the balance of Th1 cells and Th2 cells and rectify immunologic derangement.