What is the role of bosentan in healing of femur fractures in a rat model?

Bosentan, a drug used in the treatment of pulmonary hypertension, can prevent development of osteoporosis

Objective(s):

We examined the antiosteoporotic effect of bosentan (Bose) by radiographic, histopathological, and molecular methods.

Materials and Methods:

Rats were divided into 4 groups of 8 rats each: one control (Sham), one osteoporosis only (OP), and two osteoporosis groups treated with Bose doses of 50 and 100 mg/kg (OP+Bose50, OP+Bose100). Six weeks later, Bose was administered for eight weeks to animals undergoing ovariectomy. The left femoral bone of the rats was evaluated in vitro after surgical removal. Bone mineral density (BMD) was analyzed by Dual-energy X-ray absorptiometry (DEXA). Endothelin 1 (ET-1), ET-A, and ET-B expressions were examined by real-time polymerase chain reaction (real time-PCR). In addition, bone tissue was evaluated histopathologically.

Results:

Compared with the osteoporosıs group, Bose significantly increased BMD values at both 50 and 100 mg/kg doses. ET-1 mRNA levels were significantly higher in the OP group than in the Sham group, while ET-1 mRNA levels were significantly lower in Bose treatment groups. ET-A mRNA levels were significantly lower in the OP group than in the Sham group, while ET-A mRNA levels were significantly higher in Bose treatment groups. Histopathological results supported the molecular results.

Conclusion:

Our study is the first to demonstrate the molecular, radiological, and histopathological effects of Bose in preventing osteoporosis in rats.

Do peripheral melatonin agonists improve bone fracture healing? The effects of agomelatine and ramelteon on experimental bone fracture

Melatonin improves fracture healing, but the long-term use of melatonin seems impracticable in the treatment of fracture due to side effects caused by hormonal stress on chronological rhythm. Ramelteon (RAMEL) and agomelatine (AGO) are non-selective peripheral melatonin receptor (MT) agonists. This study investigated the effects on bone fracture healing of these MT agonists, which do not affect the central nervous system. The rats were divided into 6 groups, including Group 1 (SHAM): sham operated group; Group 2 (FRACTURE): femoral fracture control; Group 3 (FR + AGO30): femoral fracture + agomelatine 30 mg/kg; Group 4 (FR + AGO60): femoral fracture + agomelatine 60 mg/kg; Group 5 (FR + RAMEL3): femoral fracture + ramelteon 3 mg/kg; and Group 6 (FR + RAMEL6): femoral fracture + ramelteon 6 mg/kg. After 21 days, the rats were subjected to X-ray imaging. Bone healing was evaluated with hematoxylin-eosin (HE) staining. Messenger RNA (mRNA) expressions of bone formation markers, such as bone alkaline phosphatase (ALP), osteocalcin (OC), and osteopontin (OP), were evaluated by real-time polymerase chain reaction (RT-PCR) and with immunohistochemistry (IHC) staining. The radiographic fracture healing scores were statistically significantly higher in the FR + AGO60 group and the FR + RAMEL3 group than in the FRACTURE group. The histopathology and molecular results supported the radiographic results. It was shown that agomelatine and ramelteon increase bone fracture healing, leading to the conclusion that a preference for agomelatine, an antidepressant, and ramelteon, a sleep aid, will increase bone fracture healing in patients with fractures.

Is Ebselen A Therapeutic Target in Fracture Healing?

Objective

We investigated the effect of ebselen on fracture healing in an experimental fracture model.

Materials and Methods

We divided rats into two groups, 6 rats in each: the experimental femur fracture control group and the ebselen treatment group with an experimental femur fracture. In the experimental femur fracture control group, we created only experimental femur fracture. In the ebselen treatment group, we administered ebselen treatment with creating an experimental femur fracture. We administered ebselen intraperitoneally at 5 mg/kg once daily for 1 month after the 1st day of experimental femur fracture in the ebselen treatment group. We evaluated the recovery status of fractured femurs at the end of 1st month with radiographic, histopathological, and immunohistochemical methods.

Results

According to the radiographic fracture healing scores, ebselen treatment increased the extent of new bone formation and fracture cartilage callus significantly compared to the control group. According to the histopathological recovery scores, ebselen treatment significantly improved healing scores compared to the control group. Ebselen treatment increased the expression scores of bone healing markers in the ebselen treatment group, such as vascular endothelial growth factor and osteocalcin, compared to the control group.

Conclusion

We demonstrated that ebselen treatment increases the formation of new bone in the femur in an experimentally created femoral fracture model. Ebselen has been shown to improve the bone fracture healing in a radiological and histopathological manner, and more detailed studies are needed.

Treatment with Carnitine Enhances Bone Fracture Healing under Osteoporotic and/or Inflammatory Conditions

The aim of this study was to examine the effects of carnitine on bone healing in ovariectomy (OVX) and inflammation (INF)-induced osteoporotic rats. The rats were randomly divided into nine groups (n = 8 animals per group): sham-operated (Group 1: SHAM); sham + magnesium silicate (Mg-silicate) (Group 2: SHAM + INF); ovariectomy (Group 3: OVX); ovariectomy + femoral fracture (Group 4: OVX + FRC); ovariectomy + femoral fracture + Mg-silicate (Group 5: OVX + FRC + INF); ovariectomy + femoral fracture + carnitine 50 mg/kg (Group 6: OVX + FRC + CAR50); ovariectomy + femoral fracture + carnitine 100 mg/kg (Group 7: OVX + FRC + CAR100); ovariectomy + femoral fracture + Mg-silicate + carnitine 50 mg/kg (Group 8: OVX + FRC + INF + CAR50); and ovariectomy + femoral fracture + Mg-silicate + carnitine 100 mg/kg (Group 9: OVX + FRC + INF + CAR100). Eight weeks after OVX, which allowed for osteoporosis to develop, INF was induced with subcutaneous Mg-silicate. On day 80, all of the rats in groups 4-9 underwent fracture operation on the right femur. Bone mineral density (BMD) showed statistically significant improvements in the treatment groups. The serum markers of bone turnover (osteocalcin and osteopontin) and pro-inflammatory cytokines (tumour necrosis factor α, interleukin 1β and interleukin 6) were decreased in the treatment group. The X-ray images showed significantly increased callus formation and fracture healing in the groups treated with carnitine. The present results show that in a rat model with osteoporosis induced by ovariectomy and Mg-silicate, treatment with carnitine improves the healing of femur fractures.