The effect of methotrexate on the bone healing of mandibular condylar process fracture: An experimental study in rats

Effect of low- and high-dose methotrexate on wound healing in rats

PURPOSE

To investigate the effect of intraperitoneal treatment with low- and high-dose methotrexate (MTX) on wound healing in rats.

METHODS

The study sample consisted of 54 healthy rats. Under aseptic conditions, skin wounds were created with two circular full-thickness punch tools, 10 mm in diameter, one on the right and the other one on the left of the dorsal vertebral line. The rats were randomly assigned to one of three main treatment groups. On the 0th day (2 hours before wound creation), 7th day, and 14th day, the control group received 0.3-mL saline, the low-MTX group received 3 mg/kg MTX, and the high-MTX group received 30 mg/kg MTX, all administered intraperitoneally. The wounds were evaluated seven, 14, and 21 days after injury through morphometrical, biochemical, histopathological, and immunohistochemical analyses.

RESULTS

MTX dose-dependently decreased the degree of inflammation and angiogenesis, tissue hydroxyproline level, and HSP70 and tumor necrosis factor-α expression in the early phase of wound healing. It also suppressed epithelialization and collagen 1 expression throughout the wound-healing process.

CONCLUSION

The wounds treated with high-dose of MTX had statistically delayed wound closure on days 7, 14 and 21 compared to the saline group, while wounds treated with low-dose of MTX only had statistically delayed wound closure on day 14. In addition, weight loss was observed in rats treated with high-dose MTX, which was thought to reflect its toxicity. The dose-dependent adverse effect of MTX on wound healing may be due to its antiproliferative, antifibrotic, anti-inflammatory, and antiangiogenic effects.

Effect of Methotrexate Injection on Orthodontic Tooth Movement: An Experimental Study on Rats

INTRODUCTION

Knowledge about the effects of medications, vitamins, and various supplements on orthodontic tooth movement (OTM) is imperative for orthodontists. This study aimed to assess the effect of methotrexate (MTX) injection on OTM in rats.

MATERIALS AND METHODS

Twenty-eight male Wistar rats were randomized into four groups (n = 7). The first molar and central incisor were connected using a nickel-titanium (NiTi) coil spring with a 50 g load in each rat. The two experimental groups received 0.75 mg/kg and 1.5 mg/kg MTX, respectively, intraperitoneally for 21 days. The negative control group did not receive any injection and did not undergo orthodontic treatment. The positive control group underwent orthodontic treatment and received 0.9% saline (NaCl) injections for 21 days. All rats were sacrificed with chloroform inhalation after 21 days; their maxilla was resected, and the mean number of Howship's lacunae, blood vessels, osteoclasts, and resorption lacunae was counted. The reduction in bone volume (bone volume to total volume ratio (BV/TV)) at the site of the maxillary molar was quantified by microcomputed tomography (micro-CT).

RESULTS

OTM, the number of osteoclasts, and the number of blood vessels significantly increased in rats treated with MTX (P < 0.05). However, the increase in the number of Howship's lacunae and resorption lacunae was not significant (P > 0.05). Lower BV/TV in the MTX groups was in agreement with the increased number of osteoclasts.

CONCLUSION

Injection of MTX can significantly increase OTM and decrease root resorption in rats.

Impact of Temporomandibular Joint Discectomy on Condyle Morphology: An Animal Study

PURPOSE

Temporomandibular disorders lead to parafunctional activity that may alter bone remodeling of mandibular components. This animal study aimed to assess the impact of temporomandibular joint discectomy on condylar bone microarchitecture.

MATERIALS AND METHODS

A total of 30 one-month-old Wistar rats were assessed and divided into 3 equal groups (2 test groups and 1 control group) of 10. The first test group underwent disc removal, the second test group underwent disc and condylar cartilage removal, and the 10 remaining rats were analyzed as sham-operated controls, following a split-mouth design. The rats were killed humanely 2 months after surgery, and the respective mandibles were scanned with micro-computed tomography for quantitative morphometric analysis.

RESULTS

There were significant differences among the 3 groups analyzed (disc removal, disc and condylar cartilage removal, and sham-operated control) for bone volume fraction (ratio of bone volume to total volume, P = .044), structure model index (P < .001), fractal dimension (P = .024), and porosity (P = .023). In addition, operated and contralateral nonoperated sides significantly differed for all variables in at least 1 of the test groups (P < .05) but not in the control group (P > .05).

CONCLUSIONS

Within the limitations of this study, our results suggest that discectomy may lead to alterations of the mandibular condylar morphology.

Effect of methotrexate on bone and wound healing

INTRODUCTION

Methotrexate (MTX) is one of the most commonly used disease modifying drugs administered for wide spectrum of conditions. Through the expansion of the indications of MTX use, an increasing number of patients nowadays attend orthopaedic departments receiving this pharmacological agent. The aim of this manuscript is to present our current understanding on the effect of MTX on bone and wound healing. Areas covered: The authors offer a comprehensive review of the existing literature on the experimental and clinical studies analysing the effect of MTX on bone and wound healing. The authors also analyse the available literature and describe the incidence of complications after elective orthopaedic surgery in patients receiving MTX. Expert opinion: The available experimental data and clinical evidence are rather inadequate to allow any safe scientific conclusions on the effect of MTX on bone healing. Regarding wound healing, in vitro and experimental animal studies suggest that MTX can adversely affect wound healing, whilst the clinical studies show that lose-dose MTX is safe and does not affect the incidence of postoperative wound complications.