Use of continuous electrical capacitance and transepidermal water loss measurements for assessing barrier function in neonatal rat skin.

A vital function of the skin is to oppose the loss of water to the environment. In this study, two complementary methods, transepidermal water loss (TEWL) and continuous electrical capacitance under occlusion, were used to assess epidermal barrier function in a developmental animal model, the neonatal Sprague-Dawley rat. TEWL monitors barrier function directly while the increase in capacitance under occlusion is related to both the skin's barrier function and to its water holding capacity. Serial tape stripping of the stratum corneum on 1-day-old rat pups led to a significant increase in both TEWL and continuous capacitance measurements. Anatomic site heterogeneity and the effects of surface temperature were also studied. The ventral skin surface exhibited an increase in the continuous capacitance measurements, an effect possibly due to the thinner stratum corneum on the ventral side. Both TEWL and continuous capacitance values were directly correlated with ambient temperatures within the physiological range.