Vitamin A activation of transforming growth factor-beta1 enhances porcine ileum wound healing in vitro.

Treatment with transforming growth factor-beta(1) (TGF-beta(1)) has been shown to be effective in accelerating skin wound healing. Another approach to gain the beneficial effects of TGF-beta(1) on wound healing could be the activation of tissue stores of latent TGF-beta(1) with agents such as vitamin A. The aims of this study were to determine whether 1) vitamin A is effective in enhancing intestinal wound healing in vitro and 2) activation of TGF-beta(1) is increased during wound healing with vitamin A treatment. We used the intraluminal chemical induction model of necrotizing enterocolitis (NEC), which was adapted to the 1-wk-old piglet. Injured (NEC) and noninjured full-thickness ileum explants harvested from the piglets were cultured for 24 and 48 h in serum-free medium supplemented with all-trans retinol (ATR; 0, 2, 5, and 10 microM). All concentrations of ATR improved recovery of normal ileal wall cytoarchitecture of NEC explants, with maximal recovery observed with 2 microM ATR after 24 h of culture. Further recovery after 48 h was observed with 5 and 10 microM ATR but did not achieve the degree of healing observed with 2 microM ATR. There were no observable adverse effects of ATR on noninjured ileal explant morphology. Active TGF-beta(1) was identified only in the NEC explants incubated with ATR. The results of this study demonstrate that administration of vitamin A accelerates recovery of normal intestinal wall cytoarchitecture of injured ileum in vitro, without adversely affecting noninjured ileum. The increased activation of latent TGF-beta(1) may, in part, be responsible for the accelerated healing of injured ileum observed with vitamin A administration.

Effect of lidocaine and epinephrine on Staphylococcus aureus in a guinea pig model of surgical wound infection.

Postoperative wound infection, most often with, is of ubiquitous concern in surgical practice, occurring in an average of 1.5 to 5 percent of all procedures. The antimicrobial properties of local anesthetics have been documented over the past 25 years by in vitro studies. This study evaluates the effects of lidocaine preparations on in an in vivo setting. In a wound infection model using live albino guinea pigs, inoculum was introduced for the reproducible bacterial colonization of clean surgical wounds. One of two sites on the dorsum of each animal was infiltrated with a commercial lidocaine preparation (with and without epinephrine) prior to inoculation with (10 cfu/ml). The other site, inoculated with without preinfiltration with lidocaine, served as the control. Cultures from the sites treated with lidocaine were then compared with cultures from the control sites. All control sites had a consistent presence >or=10 cfu/ml, the threshold for bacterial inhibition of wound healing. Infiltration of the wound with 2 ml of 2% lidocaine prior to inoculation was associated with an average decrease in bacterial count of >70 percent ( n= 19). On the other hand, the addition of epinephrine (1:100,000) to lidocaine was associated with a 20-fold in bacterial counts compared with control values ( n= 10). This is the first study to demonstrate inhibition of by a local anesthetic agent in an in vivo model of a surgical wound. This information suggests a possible role for local anesthetics in prophylaxis against surgical wound infection.