Biological Effects Study Of Focused Ultrasound On Guinea Pig Model Of Chronic Eczema

BackgroundChronic eczema is a common disease which is characterized by heavily pruritus, relaps easily, local hypertrophy of the skin. Patients feel itching and cause scratching. Scratching will aggravate the rash and itching so that for a vicious cycle. As a new physical therapy the focused ultrasound has been used in the treatment of gynecological diseases, cancer, hemostasia, particularly to treat white lesions of vulva, which has a significant effect. There are many of similar points between chronic eczema and white lesions of vulva in the etiology, clinical manifestations and pathology. A lot of investigations have confirmed that, focused ultrasound can be used for the treatment of eczema. Whether focused ultrasound can be used as an effective, safe and convenient new method of physical therapy for dermatologic disease was one of important research field in ultrasound therapy.ObjectTo observe the effect and safety of focused ultrasound on guinea pig model of chronic eczema, which were prepared by using 2,4-dinitrochlorobenzene (DNCB) as an antigen to stimulate repeatedly. To investigate the possible mechanism in treating chronic eczema by focused ultrasound and to establish the theoretical basis for the clinical application of focused ultrasound.MethodsThe study is divided into four parts:1. Morphological and pathological changes: 50 healthy guinea pigs were divided into model group (40) and normal group (10), the chronic eczema models were prepared by using 2, 4-dinitrochlorobenzene (DNCB) as an antigen to stimulate repeatedly the shaved sites on the back of guinea pigs. 40 guinea pigs of model group were randomly divided into 1 W group, 2W group, 3W group, and control group. Skin tissue samples were respectively taken on 7th and 14th days after ultrasound irradiation. Samples are examined by light microscope.2. Ultrastructure changes:The chronic eczema models were prepared by using 2,4-dinitrochlorobenzene(DNCB) as an antigen to stimulate repeatedly the shaved sites on the back of guinea pigs. 32 guinea pigs were randomly divided into 4 irradiation groups and 1 control group, irradiating chronic eczema models skin in irradiation groups with CZF ultrasound therapy machine, irradiation power 3W. The samples were taken on 1,7 and 14 days after irradiation. 3. IL-2 and IL-4 detection:The normal group and model group were collect blood before ultrasound irradiation, On 7 and 14days after irradiation draw blood, detect the serum IL-2 and IL-4 concentration with enzyme immunoassay (ELISA). .4. NGF and bFGF protein determinations: The skin of the normal group and model group was taken before ultrasound irradiation, on 7 and 14day after irradiation. The NGF protein and bFGF protein in the skin was detected by immunohistochemistry.Results1. The skin of morphology and pathology of guinea pig models showed the eczematous features. After irradiation occurred immediately increased skin edema, skin integrity, slightly harder, skin temperature increased (3W> 2W> 1W), but showed no skin burns. 7 days after irradiation, skin symptom disease waning. The symptom scores of irradiation groups were obviously degraded, the significant difference could be observed between the control group and irradiation groups (P <0.05). 14 days after irradiation returned to normal.2. Histological changes: There were epidermal acanthosis of the model of eczema epidermal acanthosis, slight intercellular edema, and large of inflammatory cells infiltration in dermis. On 7^th days after ultrasound irradiation, there were significant decreases of the edema subsided, and dermal infiltration of inflammatory cells decreased. On 14th days after ultrasound irradiation a small amount of inflammatory cells infiltrated in superficial dermis, some collagenous fiber proliferated, and the others was basically normal. In control group inflammation was still obvious on 7 and 14 days after ultasound irradiation. Dermal inflammatory cell counting: It was no significant difference in 1W group (P>0.05); The significant difference could be observed between 7 days group and 14 days group of 2W group(P <0.01 ); The significant difference could be observed between the 7 days group and 14 days group of 3W group (P <0.001).3. Observation: Before ultrasound irradiation, the visible stratum corneum thickened apparently. The mitochondria of fibroblast swelled. The rough endoplasmic reticulum expanded and the intercellular space increased. 1 and 7 days after ultrasound irradiation,endothelial cell of blood vessel exist mitochondria swelling and more micropinocytotic vesicle,fibroblast have mitochondria swelling and rough endoplasmic reticulum dilatation,and merely intercellular space became smaller. On the 14^th day it returned to normal.4. It was on significant difference of IL-2 levels. Serum levels of IL-4 obviously to advance, on 7 days after irradiation the significant difference between 2W, 3W, and the model group was also observed in the level of IL-4 (P <0.01); On 14 days after irradiation, the significant difference between irradiated groups (1W, 2W, 3W ) and the control group was also observed in the level of IL-4 (P<0.001), It was no difference between radiation group and the normal group, the significant difference between 7 days and 14 days was also observed (P <0.05).5. Both NGF and bFGF protein in the epidermis were higher distinctly in the model group than in the normal group (P <0.001). On 7 and 14 days after irradiation, it was no significant difference between 1W group and the control group in the expression of NGF and bFGF protein, Both NGF and bFGF protein in the epidermis were higher distinctly in the control group than in the 2W and 3W groups (P<0.05, P<0.01). On 14 days after irradiation, 3W group closer to the normal group in the expression of NGF and bFGF protein.Conclusions1. Focused ultrasound can effectively reduce the symptom score, initial results show that 3W is safe, so guinea pig model of chronic eczema can be treated with focused ultrasound effectively and safely, the irradiation the higher dose may get the better effect under the safe dose.2. Focused ultrasound can be used to treat eczema, It is in favor of hypertrophy and rehabilitation of microvasculature and collagen fibrils, and the affected area of epithelial cells and dermal tissue tends can return to normal.3. Focused ultrasound can reduce the IL-4 levels, but have no effect of IL-2 levels, The guinea pig model of chronic eczema can be be treated with focused ultrasound, the mechanism may be related to Th2-type cytokines. 4. Both NGF and bFGF protein in tissue can return to normal by the biological effects of focused ultrasound, and then focused ultrasound is helpful to repair skin tissue.