The effect of topical caffeine on the morphology of swine hypodermis as measured by ultrasound

Background  Cellulite or lipodystrophy involves the modification of the subcutaneous adipose tissue. A wide variety of topical products is available to combat cellulite, but these have difficulties in being absorbed through the skin. One option is the therapeutic use of the ultrasound to enhance the transdermic transport of these drugs.
Aim  The objective of this study was the analysis of the effect of caffeine on the morphology of the swine hypodermis, both when applied topically and in combination with ultrasound treatment.
Methods  The following treatments were applied to the dorsal areas of five pigs (Landrace × Large White, 35 days old, weighing 15 kg each): gel, gel + ultrasound, gel + caffeine (5%, w/w), and gel + caffeine + ultrasound, daily for 15 days. A fifth area received no topical application and was used as a control. Continuous ultrasound of 3 MHz with an intensity of 0.2 W/cm² was applied at a rate of 1 min/cm². After histological processing (hematoxylin and eosin), morphometric analyses were conducted to determine the thickness and numerical profile of the hypodermis. A one-way analysis variance using a Kolmogorov–Smirnov test was conducted, with a Tukey test used to identify significant differences. A confidence level of P  ≤ 0.05 was adopted.
Results  Caffeine treatment was effective only when associated with ultrasound therapy; the combination resulted in a significant reduction in the thickness of the subcutaneous adipose tissue, as well as damage to the adipocytes, consequently decreasing the number of cells.
Conclusion  Ultrasound treatment was effective in increasing the cutaneous permeation of caffeine, as evidenced by the reduction in thickness of the hypodermis and number of adipocytes.