Effects Of Silver-nylon With Weak Direct Current On The Healing Of Partial-Thickness Scald Wound Models In Guinea Pigs

As early as 1877, Bertholon discussed the electrochemical action of cell body in his paper. Since then, many papers had published concerning the effects of electrical current on growth of the living things and electrical injuries. In 1971, Ebert and others showed that continuous current changed and strengthened bacterial sensitivity to antibiotics. By 1974, Spadaro reported that the silver ionization under direct current (DC) had anti-bacterial action. After that, many researchers including Becker, Deitch and Webster, pointed out that the positive electrode of weak DC had strong bactericidal power and good therapeutic effects for orthopedic infection and chronic myelitis. Since 1988, Prof. Zhu Zhisheng from the U.S. Army Institute of Surgical Research developed a new way to treat burn wounds by applying silver-nylon dressings with weak DC. In our experiment, we made guinea pig models withpartial-thickness scald and explore the effects of silver-nylon with weak DC on partial-thickness scalding wound healing. Materials and MethodsThe silver-nylon dressings were provided by Prof. Zhu Zhisheng from the U.S. Army Institute of Surgical Research. White guinea pigs were used as experiment animals, which weighed about 285 + 25g! Under anesthesia, they were shaved on the backs and made to lie supine. Their limbs were fixed on the Walker-Mason template and their backs were dipped into the Electro-Thermostatic Water Cabinet at 78°C for 9 seconds, so that partial-thickness scald (10% of their body surface area )were caused on the guinea pigs' backs. 60 guinea pigs were then divided into two groups at random. In the control group (SN group, N=30), on a partial-thickness scalding wound being made, silver-nylon dressings were immediately applied. The experiment group (SNDC group) was the same as the control group except that they were applied with 40uA DC current, which lasted 96 hours.The weight and burned wound area of the two groups were measured in the 1st, 2nd, 3rd, 4th, 8th, 12th weeks and growth of hair were observed. In the meantime, five animals were killed and their samples of wound underwent histopathologicalexamination at the time points mentioned above. ResultsIn the 2nd week, wounds healed in 60% of the animals in the experiment group in contrast to 28% in the control group. Wounds healed significantly earlier in the experiment group than that in the control group(P<0.05). Both in the 4th and 8th , the healed areas in the experiment group were larger than those in the control group(P<0.05). In the 12th week, the healed areas in the experiment group were larger than the original ones by 18.64% (concomitancy with their body weight increase)with rich growth of hair, while the healed wounds in the control group were smaller than the original ones by 18.18%. The two groups were of significant difference.Each specimen was stained with haematoxylin and eosin.Microscopic examination showed that all animals in both group had completely reepithelialized wounds by 4 weeks postburn. In the experiment group ,epidermis was thick.Dermis contained numerous hair follicles. In contrast, in the control group epidermis was thin. Surviving hair follicles were rare. ConclusionSilver-nylon dressings with weak DC can promote the healing of the partial-thickness scald wounds of guinea pigsand reduce the shrinking of healed surface area.