Influence of gel matrix on the wound healing activity of adhesive dressings filled with silver nanoparticles and humic acid applied on a rat burn model

BACKGROUND: Thermal injuries to the skin (burns) are common household and man-made traumatic injuries in humans. In wartime, thermal injuries are additional damaging factors in combined skin lesions caused by the damaging elements of modern weapons.

AIM: This study aimed to evaluate the effectiveness of gels based on silver nanoparticles in combination with humic acid on the healing of thermal skin injuries (burn wounds) in rats.

MATERIALS AND METHODS: In the experiments on 57 white nonlinear male rats weighing 218–260 g, the wound healing effects of gels with 10% humic acid modified with nanosilver on various bases, prepared in a pharmacopoeial manner, on a grade IIIB thermal skin burn model were examined. The gel bases used in three experimental groups were as follows: sodium carboxymethylcellulose (group Ia, n = 12), polyacrylamide (group Ib, n = 12), and polyethylene glycol (group Ic, n = 12). The comparison group (group II, n = 12) received Levomekol ointment, whereas the control group (group III, n = 8) did not receive treatment. A grade III thermal burn was made on the proximal part of the back under general anesthesia using a thermal applicator with a circular-shaped flat working part with a diameter of 20 mm. Seventy-two hours after the burn, the wound was freed from scab by complete excision along the border of the intact skin, a splinting ring was applied, and the study drugs were administered. The dynamics of the changes in the burn wound were assessed on days 10, 14, 17, 21, 24, and 28 using the Universal Desktop Ruler program.

RESULTS: The average times (median) to reach 75% epithelialization of wounds in groups Ia, Ic, and II were 29.4 ± 0.2, 34 (33–34), and 33.3 ± 0.45 days, respectively, whereas in groups Ib and III, the median time to 75% epithelization was not achieved. The 28-day healing index (%/day) values were 8.6, 4.8, 6.5, 6.1, and 4.4 in groups Ia, Ib, Ic, II, and III, respectively. The dynamics of epithelialization of thermal burns were most pronounced in group Ia, where the sodium carboxymethylcellulose acted as a gel base for humic substances modified with nanosilver.

CONCLUSIONS: The results indicated that the gel added with nanosilver-modified humic substances based on sodium carboxymethylcellulose has a wound healing effect on thermal skin injuries, superior to the effect of the reference drug Levomekol in terms of the healing time of burn wounds.