| Objective:Carbon light phototherapy can advance wound healing by promoting the epithelial cells proliferation.However,the warming effect caused by phototherapy will lead to a local dry microenvironment,which is not compatible with moist healing theory.Hydrogel dressings contain a large amount of water that can penetrate deep into the wound to provide a humid environment,which can offset the dry microenvironment caused by carbon light.Apart from that,it can also serve as a three-dimensional network of epithelial cell proliferation.Therefore,the combination of carbon light and hydrogel may be a new idea for clinical wound care.This article systematically studied the role and related mechanisms of carbon phototherapy combined with prontosan hydrogel to promote wound healing from the basic and clinical directions,and prospected the application prospect of this treatment method in wound care.Method:Firstly,in order to explore the optimal treatment parameters of carbon phototherapy,the dehydration of prontosan hydrogel and the viability of fibroblasts were analyzed when exposed to different light time and distance.After that,the synergistic effect of combined prontosan hydrogel and carbon phototherapy on full-thickness skin defects in rats was evaluated:a total of 32 experimental animal models of rat skin resection wounds were established,which were randomly divided into 4 groups:Rat wounds in Control group（BLA）were given only iodophor disinfection;Rat wounds in hydrogel group were treated with 200μL prontosan hydrogel（GEL）after routine iodophor disinfection;Rats wounds in carbon light group（CPT）received iodophor disinfection,and were given carbon light for 15minutes at 20cm from the wound（refer to the results of the previous experiment）;In the experimental group（G&C）,the skin wounds of the rats were treated with 200μL prontosan hydrogel after disinfecting the wounds,and additional light treatment for 15 minutes at20cm from the wound.Treatments were performed every 2 days,and the experimental animals were scarified on the 8th and 16th days of treatment.The wound healing was quantitatively analyzed by the residual wound area.After the animals were sacrificed,ELISA experiments were performed on the regenerated skin tissues to detect the secretion of growth factors（TGF-β1,VEGF and bFGF）,and tissue section staining（HE and Masson staining）and immunohistochemistry methods were used to collectively analyze wound healing condition（Such as scar formation and keratin secretion）.Finally,this study conducted a quantitative analysis of inflammatory cells,maturity score,and neovascularization.Results:This study confirmed that when the light source was 20 cm away from the hydrogel,the dehydration effect of the hydrogel was not obvious.When the light source distance from the hydrogel was reduced from 15cm to 5cm,the dehydration effect of the hydrogel obviously increased.At the same time,with the extension of light duration,especially when the light duration was≥20min,the dehydration effect trend of hydrogel obviously increased.When the light duration was set to 5-15min,the dehydration effect was not obvious.Fibroblasts survival results showed that when the light duration was less than15 minutes,the fibroblasts retained high viability,while when the light duration was greater than 15 minutes,the cell survival rate was significantly reduced.Moreover,once the distance was≤20 cm,the survival rate of fibroblasts was significantly reduced.It can be seen from the external appearance of the wound that wound healing in the G&C group was more rapid than those in other three groups,beginning from 4 days post-wounding.New skin tissue could completely fill in the skin defect by 14 days,while wounds were fully healed by 16 days in the CPT group.In the GEL group,wounds almost completely healed before sacrifice,while in the BLA group wounds remained visible and were not well-healed.There was a statistical difference in the quantitative analysis of the residual wound area between the groups（P<0.05）.At early stage of wound repair（8 days）,the secretion of TGF-β1 from G&C group(27.97±1.41 ng L-1)was higher than BLA(17.25±1.74 ng L-1),GEL(18.16±2.97 ng L-1)and CPT(22.37±0.92 ng L-1)groups（P<0.05）.While,tissue obtained from the G&C group(25.52±3.76 ng L-1)expressed the highest level of VEGF,and the value of CPT group(19.23±2.74 ng L-1)was significantly higher than those in the GEL and BLA groups(11.08±1.12 ng L-1,10.07±1.04 ng L-1,respectively).Meanwhile,the bFGF expression showed the similar trendy.At the late stage of wound repair（16 days）,the secretions of TGF-β1 and VEGF from G&C(37.50±4.02 ng L-1,33.67±4.37 ng L-1)and CPT(34.35±2.42 ng L-1,29.80±4.41 ng L-1)groups were significantly higher than BLA(25.19±1.32 ng L-1,17.36±2.61 ng L-1)and GEL(28.37±2.13 ng L-1,19.08±2.52 ng L-1)groups（P<0.05 and P<0.01,respectively）.Differently,it was observed that the expressions of bFGF from the G&C and CPT groups(4.32±0.73 ng L-1,3.77±0.65 ng L-1,respectively),which were significantly higher than those in the GEL and BLA groups(2.87±0.63 ng L-1,2.19±0.26 ng L-1,respectively).By tissue staining,we observed that samples from the G&C group exhibited well-organized granulation tissue at the defect site on day 8,while complete healing of skin defect was observed by 16 days.In contrast,poor granulation tissue was detected in the BLA group at 8 days,and rich granulation tissue formation was verified by 16 days.In the GEL and CPT groups,formation of granulation tissue were relatively superior to those in the BLA group,while they were inferior to those in the G&C group,particularly at the earlier time point（day 8）.Inflammatory cells infiltration statistics indicated that the numbers of inflammatory cells from G&C（19.68±3.67,10.38±1.56）,CPT（22.47±3.39,12.34±1.38）and GEL（20.48±3.35,11.31±3.49）groups were significantly lower than that of BLA（37.60±3.34,25.27±4.41）group at both 8 and 16 days（P<0.01 and P<0.05,respectively）.There was no statistical difference between the three groups of G&C,CPT and GEL.The observation of scar tissue formation showed that the G&C group exhibited less scar tissue formation and more collagen deposition,while the CPT group experienced less scar tissue formation and more collagen deposition than the GEL and BLA groups at both 8and 16 days.Further,the BLA group exhibited minimal collagen deposition and the most scar tissue formation among the groups.According to the wound sub-epithelial dermal matrix maturity scoring system,the G&C（3.41±0.49,4.48±0.76）and CPT groups（2.87±0.79,3.55±0.72）at both 8 and 16 days achieved higher maturation scores than those of GEL（1.16±0.27,1.98±0.17）and BLA（0.64±0.12,1.18±0.26）groups.However,there was a significantly higher level of maturation in the G&C group than the CPT group at 16days;the phenomenon was also observed between GEL and BLA groups at the same period.The expression results of keratin（K14 positive region）in the regenerated tissues of each group showed that,on days 8 and 16,increased K14-positive area was observed in the G&C group,compared with those in the CPT and GEL groups.In addition,the lowest K14expression levels at each time point were observed in the BLA group.In addition,the quantitative results of the number of blood vessels showed that,on days 8,elevated numbers of K14-positive cells were observed in the G&C and CPT group（5.47±0.52,4.27±0.48,respectively）,compared with those in the GEL and BLA groups（2.38±0.23,1.71±0.29,respectively）.When it came to 16 days,numbers of CD31-positive vessels were clearly highest in the G&C group（12.55±0.81）,indicating superior angiogenesis and blood vessel formation in granulation tissue.Further,samples from the CPT group（10.53±0.72）exhibited more angiogenesis than those from the GEL and BLA groups（7.05±0.61,4.28±0.26,respectively）.Conclusion:Appropriate treatment parameters should be set for carbon phototherapy,of which the duration should be set to 15 min,and the light source should be placed at a distance of 20 cm.Compared with monotherapy such as iodophor disinfection,prontosan hydrogel or carbon phototherapy,the speed of wound healing in the carbon phototherapy combined with hydrogel group increased significantly,and the quality of the granulation tissue of the regenerated tissue was better,scar formation and inflammatory cell infiltration decreased,and collagen deposition and neovascularization increased significantly.This combination therapy has the advantages of safety,reliability and practicality.It can be used as a novel wound care and treatment method to treat wounds,and provide new ideas for clinical wound care decision-making. |
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