Effects Of Folic Acid On Diabetes-induced Delayed Wound Healing In Mice

Objective To investigate the effect of folic acid supplementation on diabetes-induceddelayed wound healing in mice and to explore the underlying mechanism.Methods ICR mice were randomly selected into either control group or diabetic group.Mice of diabetic group were injected intraperitoneally with STZ (50mg/kg) in citratebuffer solution for five days while mice of control group were injected intraperitoneallywith citrate buffer solution alone. The blood glucose concentration were checked beforethe first injection and72h after the last injection by collecting the tail vein blood, thediabetic model was considered to be successful when the blood glucose concentrationwas above250mg/dl. After building the diabetic model successfully, the mice weredivided into three groups: control group, diabetes mellitus group (DM group) anddiabetes mellitus with folic acid supplementation group (DM+FA group). Skin woundswere made for all mice and take the completion time of wound-making as day0. Toobserve the wound healing every day during the experiment, including wettability, color,secreta, shape and the edge of the wound. Using the transparent film to accuratelydescribe the wound on day0,3,6,9and12and count the healing rate on every moment.On day0,3,6,9and12, six mice in every single group were chosen to be anesthetizedto death, and then took a certain part of skin tissue of the wound for the histologicalexamination, part of the skin tissues could be applied to measure the content ofhydroxyproline; the skin tissue of day6were dissected for measurements of GSH,MDA and NO contents. The protein expressions of3-NT was measured by westernblotting. The rest mice could be observed until the complete healing with an accurate record of the healing time. The tail vein blood was collected to check the blood glucoseconcentration before the experiment over.Results After five days’ intraperitoneal injection of STZ (50mg/kg), the diabetic miceshowed a poor spirit, which reflects on hair tarnished, withered and loosened, and alsoan obvious loss of weight.72hours after the last injection, the blood glucoseconcentration was above250mg/dl, and the figure remains that high until the end. Asfor the structure of wound based on the diabetic mice model, the time needed forcompletion healing was12.08±1.08days in Control group, and14.00±2.00days for DMgroup which was obviously delayed compared with the former one, and the figure inDM+FA group was12.73±0.79days that costs less than DM group. From the record, onday3,6,9and12, there was no difference of the wound healing rate between Controlgroup and DM+FA group. Comparisons of differences at each time between Controlgroup and DM group, DM+FA group and DM group were enough to be statisticallysignificant. As can be learned from the observation of morphology and histology, thewound healing of mice delayed in DM group; and on day3,6,9and12, the content ofhydroxyproline of all three groups was rising, and specifically speaking, from the viewof the content of hydroxyproline at each time point, DM group was noticeably less thanControl group, and DM+FA group represented a larger number than DM group on day6,9and12. From the measuring of the content of GSH, MDA and NO, and the proteinexpression levels of3-NT of the skin tissue of the wound on day6, what can be seenwas that in DM group compared with Control group, the content of GSH and NOdecreased, the content of MDA increased, and the protein expression levels of3-NTalso showed an increase. After folic acid supplementation, there would be a decrease ofMDA and3-NT level, and an increase at the respect of NO, the level of GSH could bedecreased, as well as the oxidative damage of organism could be eased.Conclusions Some conclusions can be safely summarized as follows:(1) Folic acid supplementation has protective effects on diabetes-induced delayed wound healing inmice.(2) Folic acid supplementation could protect the diabetes-induced delayed woundhealing may be associated with suppression of oxidative stress and increase of NO levelon the wound tissue.