The Inhibiting Effect Of Artesunate On The Hypertrophic Scarring In Rabbit Ears Model

Objective This study was aimed to establish stable and reliable animal model of rabbit ear for hypertrophic scar and to dynamic observe the change of wounds healing and the inhibiting effect of Artesunate on the formation of hypertrophic scar .Methods①Four New Zealand rabbits of either weighing 2.5±0.3 kg were used to establish animal model for hypertrophic scar. Six wound surfaces in size of 1㎝×1㎝ were created down to bare cartilage on the ventral surface of each ear. On days 3,7,11,14,18,28,56,84 after modeling ,the change of texture and healing of wound surface were observed. The hypertrophic index (HI),the rate of scars and morphological change of scars were detected by Hematoxylin and eosin and Van Gieson. The content of hydroxyproline was tested using chloramine T methods .②Sixteen healthy purebred adult New Zealand rabbits of either weighing 2.5±0.3 kg,were taken as experimental animals and randomized into experimental A,B,C group and control group .Each group contained 4 rabbits. The scar models in ears were reproduced after the rabbits were fed for 24 hours. Six wound surfaces in size of 1㎝×1㎝ were created down to bare cartilage on the ventral surface of each ear .There were 48 surfaces in each group .The scars of experimental A,B,C group were each received Artesunate by local injection in different dose of 40,80,120 g/l on postoperative 6th day .20μl pre-scar every three days for 6 times .The scars of control group were treated with 50g/l sodium bicarbonate by local injection 20μl pre-scar every three days for 6 times. On postoperative 28th and 56th day the hypertrophic index (HI) and morphological change of scars were observed by Hematoxylin and eosin and Van Gieson staining. The content of hydroxyproline was tested using chloramine T methods. The expression of PCNA in protein level was detected with immmunohistochemistry and Western blotting methods.Results 1.There were numerous fibroblasts proliferation and collagen fibers were found On postoperative 11th and 14th day . Collagen fibers were swirls and formed collagen node on 28th of postopration. 2.Sixteen experimental rabbits were involved in the final analysis.①Compared with the control group,HI of the artesunate treated groups was significantly reduced in a dosage dependent manner(P<0.05).②The proliferation of fibroblast was obviously inhibited and the contents of collagen fiber were decreased in the artesunate treated groups than that of the control group under microscope in Hematoxylin-eosin staining.③Compared with the control group,the dermises of the scars in the artesunate treated groups were thinner and contained a few fibroblasts . Collagen fibers were well-arranged and no collagen node or collagen node was not signifance .Meanwhile , more and more fibroblasts and collagen fibers were found in the control group . Collagen fibers were swirls and formed collagen node.④Compared with the control group,the content of hydroxyproline in the artesunate treated groups were decreased (P<0.05).⑤Immunocytochemistry showed that the nuclear expression of PCNA was staining less in the artesunate treated groups than that of the control group and western blotting were declared that the expression of PCNA in protein level of the artesunate treated groups were decreased than that of the control group (P<0.05).Conclusion 1. Using the methods of this experimental , animal model was stable and reliable and could be made used to dynamic study the prevention and cure effect of the drug on the hypertrophic scar . 2. The conversion of normal scarring to hypertrophic scarring in rabbits occured at 11～28 days after operation.3. Artesunate could significant inhibit formation of hypertrophic scar in rabbit ears and prevent its developing. 4. The inhibiting effect was in a dose dependent manner. The inhibiting effect of 120g/l was the most significant.