Study On Effect And Mechanism Of Cajanus Cajan Leaf On Acute Radiation Dermatitis

The studies about radioresistance are increasing as the universal attention of radialization endangering the normal life of people.Nuclearleak of Janpan has aroused our regard again.This study was researching about the acute radiodermatitis chiefly.Radiodermatitis is the common side reaction of actinotheraphy to malignancy. Basal layer cell should be injured by free radicals and active oxygen which are produced by ionizing radiation.The biological effect is expressing as the DNA damnification.The mechanism of damnification is complicated and the damage of organism is serious.The foreign medicine used for treatment can’t fulfil the patients’ requirements.Nowadays, Many researchers attach importance to study of Chinese Pharmacy. The active constituents of Chinese Pharmacy are abundance,so there are many acting targets, The multiway methods of administration and the less adverse reaction are also the advantages of Chinese Pharmacy. Our university have researched Cajanus cajan leaf for many years, Hao Yuan,YongqiFang and Yong Tang had discovered that it was effective for Cajanus cajan leaf improving the healing of skin wound and geting rid of the skin inflammation.In this study,we using the extraction of Cajanus cajan leaf for experimentation, make sure the effect of the extraction to prevent and therapy acute radiodermatitis;and research the function and relativity with the DNA double strand break(DSB) repair protein Ku70/80,to explore the mechanism of Cajanus cajan leaf influencing radiodermatitis.So Cajanus cajan leaf is expected to be a effective developed medicine to prevent and cure acute radiodermatitis.Purpose:From observating the occurrence and healing of wound and wound tissue pathological changes of Acute radiation dermatitis pharmacological rat models,which was injured by beta ray radiation and daubed with the cajan leaf extract,we would determine the pharmacodynamics efficacy of the cajan leaf extract;And from detecting Ku70, Ku80mRNA,we would explore the mechanism of cajanus cajan effecting of radioactive dermatitis.Method:1. Pharmacodynamic study of Cajanus cajan leaf extract to acute radiation dermatitis1.1Grouped and treated the rats Divided40SD female rats into4groups randomly, each group of10, as blank control group, radiation pattern group, Cajanus cajan leaf group and positive control(biafine)group,respectively.Blank control group without radiation treatment; The rats of radiation pattern group, Cajanus cajan leaf group and positive control group should be gave radiation injury on the buttock skin.The second day after the radiation, The rats of Cajanus cajan leaf group and positive control group should be daubed with the corresponding drug1G/kg in the irradiated site alter saline debridement, two times a day, keeping the medicine60days after radiation.The radiation pattern group was given saline debridement only. The blank control group was not given any medicine treatment.1.2Built the cute radiation dermatitis modelRemoved the hair of irradiated site of rats with paste consisted of saturated sodium sulfide and equivalent amount of talcum powder, Abdominal anaesthesia with0.3%pentobarbital sodium at the dose of10mL/kg,and doing a single irradiation6MeV bata ray fired by linear accelerator on the gluteal skin. Irradiation distance of1m, the dose rate of200cGy/min, the irradiation time for15min, the dose of30Gy, irradiated area of2cm X4cm, around the site shielded with leading of10cm.1.3Observing the activity and the appearance of the wound of each groups rats; In the15,30,45,60days after irradiation, measured healing area of each rat’s wound, and converted to the healing rate. Rated the wound appearance and diagnostic classification; recorded the healing time.2. Mechanism research of Cajanus cajan leaf extract effecting on acute radiation dermatitis2.1Grouped and treated the rats Divided10from100SD female rats randomly, as blank control group; Divided the other90rats into3groups randomly,each group of30, as radiation pattern group, Cajanus cajan leaf group and positive control group, respectively. The method of radiation model and administration was as1.1.Sacrificed6rats of each groups in2,8,15,30,45clays after radiation, except the blank control group should be sacrificed2rats. 2.2Sampled and detected Cut3pieces of buttock skin wound tissues from each rats of the radiation field,the first for light microscopic observation;the second stored in low temperature for transmission electron microscopic observation;and the third for detecting the content of Ku70, Ku80mRNA using real time fluorescence quantitative PCR method.3. Statistical process Used SPSS16.0software to conduct statistical analysis, using analysis of variance for multiple groups comparison;Used Q test for comparison of the two groups. Inspection standard of a=0.05.Result:1. Compared with the rats of radiation pattern group, of the rats of Cajanus cajan leaf group,the time of emergence of wound was delayed, the skin injury wound and ulcer was a lesser degree, the wound healing rate was larger and healing time was reduced; In the process of wound healing, the activity of rat is more normal. Compared with radiation pattern group, The wound healing rate of Cajanus cajan leaf group in the30,45,60days were statistically significant(P<0.05);the score of wound appearance of Cajanus cajan leaf group in the45,60days were statistically significant(P<0.05);. The healing time was also statistically significant(P<0.05).2. Each period after the radiation,Used light microscopy and transmission electron microscopy,more fibroblasts, epithelial cells, endothelial cells, dermal connective tissue and collagen fiber can be observed during the skin wound tissue of rats of Cajanus cajan leaf extract group than the rats of radiation group. And cells ultrastructure was damaged lighter than the radiation group. And the Ku70, Ku80mRNA expression in wound tissue of Cajanus cajan leaf extract group were higher than the radiation group’s, the results were statistically significant(P<0.05).Conclusion:Cajanus cajan leaf extract can improve the radiation injured epidermal tissue,delay the apoptosis of cell, relieve the severity of radiation injured wound. At the same time promote capillary angiogenesis and repair tissues of itself. The high expression of Ku80mRNA in Ku70, may be associated with radiation injury caused by DNA fracture repair. Cajanus cajan leaf extract promote the synthesis of collagen and promote wound healing possibly by increasing DNA repair protein expression.