The effects of phytoestrogens on fracture healing: experimental research in New Zealand white rabbits.

BACKGROUND: Phytoestrogens are plant-derived natural molecules having some bone forming and bone substituting effects. In the present study, the role of phytoestrogens on bone healing was investigated in a rabbit fracture model. METHODS: Twenty-two New Zealand white rabbits with right tibia fracture were divided into two groups randomly. The plant derived extract of Vitex agnus-castus L. (Verbenaceae) prepared before the study was administered intramuscularly in group 1 and group 2 was chosen as control. Fracture healing was monitored in weekly basis with blood alkaline phosphatase level, radiographs of extremities and 99m-Tc MDP bone scintigraphy. The study was finished at the end of the 3rd week. The extremities including tibial fractures were collected for histological examination. RESULTS: Radiographic evidence of fracture healing obtained on postoperative day seven was superior in group 1 than control group (p<0.01). The 99m-Tc MDP bone scintigraphy uptake ratios on postoperative seventh day showed higher uptake in group 1 than in group 2 (p<0.05). The differences of scintigraphic uptakes in fractured tibias calculated on postoperative seventh day and postoperative 14th in group 1 were higher than group 2 (p=0.04). The histopathologic evaluation performed after sacrification of all rabbits on postoperative 25th day showed no significant difference between both groups. No statistical difference was determined related to the other variables. CONCLUSION: Flavonoids affected positively the early periods of fracture healing mechanism in New Zealand white rabbits. We suggest further studies with phytoestrogens to determine the effects of various dosages and administration ways.

The effects of topical tripeptide copper complex and helium-neon laser on wound healing in rabbits.

The aim of this study was to compare the clinical and histopathological effects of tripeptide copper complex (TCC) and two different doses of laser application (helium-neon laser, 1 and 3 J cm(-2)) on wound healing with untreated control wounds. Experimental wounds were created on a total of 24 New Zealand white rabbits and topical TCC or laser was applied for 28 days. The wounds were observed daily, and planimetry was performed on days 7, 14, 21 and 28 to measure the unhealed wound area and percentage of total wound healing. Biopsies were taken weekly to evaluate the inflammatory response and the level of neovascularization. The median time for the first observable granulation tissue was shorter (P < 0.05) in the low and high dose laser groups than in the control group (3 and 2.66 vs. 4.5 days), but was not different between the TCC and control groups (4.16 vs. 4.5 days). Filling of the open wound to skin level with granulation tissue was faster (P < 0.05) in the TCC and high dose laser groups than in the control group (14 and 16 vs. 25 days), but was not different between the low dose laser and control groups (23 vs. 25 days). The average time for healing was shorter (P < 0.05) in the TCC and high dose laser groups (29.8 and 30.2 vs. 34.6 days), but was not different between the low dose laser and control groups (33.8 vs. 34.6 days). Histopathologically, wound healing was characterized by a decrease in the neutrophil counts and an increase in neovascularization. The TCC and high dose laser groups had greater neutrophil and vessel counts than in the control group, suggesting a more beneficial effect for wound healing.