Wrapping With Basic Fibroblast Growth Factor-Impregnated Collagen Sheet Reduces Rat Sciatic Nerve Allodynia.

Autologous vein wrapping is used to treat recurrent chronic constriction neuropathy and traumatic peripheral nerve injury. However, its use is restricted due to the inability to obtain sufficiently long veins for larger grafts. We previously reported that vein-derived basic fibroblast growth factor (bFGF) promotes heme oxygenase-1 (HO-1), which reduces allodynia via its anti-inflammatory properties. To mimic vein wrapping, we developed a collagen sheet impregnated with bFGF. Chronic constriction injury (CCI) was induced in male Wistar rats as a model of sciatic nerve injury, and the rats were divided into three groups: (i) untreated after CCI surgery (control group), (ii) treated with a collagen sheet wrap impregnated with phosphate-buffered saline (PBS/CS group), and (iii) treated with a collagen sheet wrap impregnated with bFGF (bFGF/CS group). Pain behavior (von Frey test) was evaluated on postoperative days (PODs) 1, 5, 7, and 14. Quantitative polymerase chain reaction was conducted on sciatic nerve RNA to quantify HO-1 gene, Hmox1, expression. Enzyme-linked immunosorbent assay were used to determine HO-1 protein levels on POD 1. von Frey testing showed significantly greater pain hypersensitivity in the control and PBS/CS groups than the bFGF/CS group. In the bFGF/CS group, Hmox1 messenger RNA and HO-1 protein levels were significantly increased in the sciatic nerve compared with the control and PBS/CS groups on PODs 1 and 5 and POD 1, respectively. The bFGF/CS group showed decreased allodynia and HO-1 induction, as observed with vein wrapping. Therefore, local application of bFGF may be an alternative treatment strategy for compressive neuropathy and peripheral nerve trauma in clinical settings. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2258-2263, 2019.

Efficacy of nerve growth factor antibody in a knee osteoarthritis pain model in mice.

BACKGROUND: Nerve growth factor (NGF) is not only an important factor in nerve growth but also a major contributor to the production of inflammation. It has been reported that inhibiting NGF could reduce several types of pain in several animal models. Here, we aimed to clarify the efficacy of NGF antibody in a knee osteoarthritis (OA) pain model in mice. METHOD: Six-week-old male C57BR/J mice were used (n = 30). Ten mice comprised the control group, which received saline injection into the right knee joints; the other 20 mice comprised the experimental group, which received monoiodoacetate (MIA) injection into the right knee joints. Three weeks after surgery, the 20 experimental mice were randomly placed into treatment groups which received either sterile saline (non-treat group: 10 mg/kg, i.p.) or an anti-NGF antibody (anti-NGF group: 10 mg/kg, i.p.). Simultaneously, all mice received fluorogold (FG) retrograde neurotracer injection into their right joints. In a behavioral study, we evaluated gait using the CatWalk quantitative gait analysis system before surgery, 3 weeks after surgery (before treatment), 4 weeks after surgery (one week after surgery), and 5 weeks after surgery (2 weeks after surgery). In immunohistochemical analysis, the right dorsal root ganglia (DRGs) from the L4-L6 levels were resected 5 weeks after surgery (2 weeks after surgery). They were immunostained for calcitonin gene-related peptide (CGRP), and the number of FG-labeled or CGRP-immunoreactive (IR) DRG neurons was counted. RESULTS: On gait analysis using the CatWalk system, duty cycle, swing speed, and print area were decreased in non-treat group compared with those in control group and improved in the anti-NGF group compared with those in non-treat group. CGRP expression in DRGs was up-regulated in non-treat group compared with that in control group and suppressed in the anti-NGF group compared with that in non-treat group (both p < 0.05). CONCLUSIONS: MIA injection into the knee joint induced gait impairment and the up-regulation of CGRP in DRG neurons in a knee OA pain model in mice. Intraperitoneal injection of anti-NGF antibody suppressed this impairment of gait and up-regulation of CGRP in DRG neurons. These finding suggest that anti-NGF therapy might be valuable in the treatment of OA pain in the knee.

Acceleration of callus formation during fracture healing using basic fibroblast growth factor-kidney disease domain-collagen-binding domain fusion protein combined with allogenic demineralized bone powder.

BACKGROUND: To repair fractures with large bone defects or gaps, demineralized allogenic bone matrix (DBM) is often applied to the fracture site. However, studies have shown that the use of DBM alone has limited efficacy for repairing fractures. In the present study, we developed an allogenic demineralized bone powder (DBP) with basic fibroblast-derived growth factor containing a polycystic kidney disease (PKD) domain and collagen-binding domain (CBD) from Clostridium histolyticum collagenase (ColH) and investigated the stimulatory effects of bFGF-PKD-CBD combined with allogenic DBP on bone growth in a mouse femur fracture model. METHODS: DBP mixed with either phosphate-buffered saline (PBS) (DBP/PBS), 0.58 nmol basic fibroblast growth factor (bFGF) (0.58 nmol DBP/bFGF), 0.058 nmol bFGF-PKD-CBD (0.058 nmol DBP/bFGF-PKD-CBD), or 0.58 nmol bFGF-PKD-CBD (0.58 nmol DBP/bFGF-PKD-CBD) was grafted into fracture sites. RESULTS: bFGF-PKD-CBD/DBP composite accelerates callus formation in a bone fracture model in mice and clearly showed that the composite also increases bone mineral density at fracture sites compared to bFGF/DBP. In addition, bFGF-PKD-CBD/DBP increased callus volume and bone mineral content to similar levels in fractures treated with a tenfold higher amount of bFGF at 4 weeks. CONCLUSIONS: Our results suggest that bFGF-PKD-CBD/DBP may be useful for promoting fracture healing in the clinical setting.

Differential age-related bone architecture changes between female and male STR/Ort mice.

The incidence of spontaneous osteoarthritis (OA) in female STR/Ort mice is much lower than that observed in male STR/Ort mice; however, the reason for the differential incidence of OA between sexes has not been elucidated. Here, we investigated and compared age- and sex-related bone mineral density and architectural changes in male and female STR/Ort mice. Bone architecture and bone mineral density (BMD) of femurs were examined in 5-, 10-, 15-, 20-, and 35-week-old male and female STR/Ort mice by microscopic computed tomography (µCT). Angular degrees of internal tibial torsion (ADITT) were also measured in mice at 5, 15, and 35 weeks of age. Earlier decreases of cancellous volume and BMD were found in male STR/Ort mice. Using µCT, an age-related decline of bone marrow space in femoral diaphysis was observed in both males and females but was more dramatic in females. In addition, an earlier increase of ADITT was observed in male STR/Ort mice, suggesting that internal rotation of the tibia may contribute to OA. Age- and sex-related bone architectural changes clearly differ between male and female STR/Ort mice. These differences in bone structure, particularly ADITT, may explain the differential incidence of OA in STR/Ort mice.