Low-level laser therapy (LLLT) at 830 nm positively modulates healing of tracheal incisions in rats: a preliminary histological investigation.

OBJECTIVE: The aim of the present study was to evaluate whether LLLT at 830 nm is able to positively modulate trachea incisional wound healing in Sprague-Dawley rats. BACKGROUND DATA: Tracheotomy may be associated with numerous complications. Development of excess granulation tissue represents a late complication that may lead to airway occlusion. Low-level laser therapy (LLLT) has been shown to have stimulatory effects on wound healing of different tissues. Therefore, it may be suggested that LLLT could be able to positively modulate trachea wound healing as well. MATERIALS AND METHODS: Using general anesthesia, a median incision was performed from the second to the fifth tracheal cartilage ring in 24 rats. Animals were then randomly divided into sham-irradiated control and laser-treated groups. LLLT (power density: 450 mW/cm(2); total daily dose: 60 J/cm(2); irradiated area ∼1 cm(2)) treatment was performed daily during the first week after surgery. Samples for histological evaluation were removed 7 and 28 days after surgical procedure. Histological sections were stained with hematoxylin-eosin and van Gieson. RESULTS: Results from our investigation showed that LLLT was able to reduce granulation tissue formation and simultaneously increase new cartilage development at both evaluated time intervals. CONCLUSIONS: From this point of view, LLLT at 830 nm may be a valuable tool in trachea wound healing modulation. Nevertheless, further detailed research is needed to find optimal therapeutic parameters and to test these findings on other animal models.

Postsurgical administration of estradiol benzoate decreases tensile strength of healing skin wounds in ovariectomized rats.

BACKGROUND: The most effective method of increasing the level of estrogen in the wounds of post-menopausal women undergoing routine surgical procedures is by long-term preoperative administration. However, in the case of acute surgery or trauma, the most effective method of increasing the level of estrogen is administration immediately pre- or postsurgery. This study, therefore, was aimed at assessing the effect of postsurgical administration of estradiol benzoate on wound healing in ovariectomized (OVX) Sprague Dawley rats. MATERIALS AND METHODS: Three months prior to the wound healing experiment, 16 rats were anesthetized and underwent ovariectomy, while the other eight rats were sham operated. Two parallel full thickness skin incisions and two round full thickness skin excisions were performed on the dorsum of each rat. Dose of 10 microg/d of estradiol benzoate was administered to eight OVX rats for 6 d postoperatively, whereas the other animals received a placebo. After 6 d, all animals were sacrificed and samples removed for biomechanical and histological evaluation. RESULTS: The mean wound tensile strength of OVX estrogen treated rats (9.54 +/- 3.24 g/mm(2)) was significantly lower compared with vehicle-treated OVX animals (14.57 +/- 4.12 g/mm(2)) as well as with control rats subjected to sham-OVX surgery (11.71 +/- 3.33 g/mm(2)). Nevertheless, the histological evaluation in OVX estrogen treated rats showed a significantly increased process of neo-angiogenesis associated with slightly decreased collagen deposition. CONCLUSION: Our results indicate that the question of the clinical significance of this type of hormone replacement therapy remains open and requires further research.