Response of Rat Tibia to Prolonged Unloading Under the Influence of Electrical Stimulation at the Dorsal Root Ganglion.
PURPOSE
Immobilization of weight bearing skeletons or microgravity results in disuse osteoporosis in both human and animals. Our previous study demonstrated that electrical stimulation at the dorsal root ganglion (DRG) with an implantable micro-electrical stimulation system (IMESS) could trigger secretion of bone anabolic calcitonin gene-related peptide (CGRP) and prevent bone loss in a short-term hindlimb unloading rat model. This study was designed to further investigate whether electrical stimulation to the DRG could prevent bone loss due to prolonged unloading.


METHODS
Eighteen adult rats were randomly assigned into three groups: cage control (CC), hindlimb unloading (HU), and hindlimb unloading with electrical stimulation (HUES). Electrical stimulation was applied via IMESS to the right DRGs at vertebral levels L4-L6 in HUES group for 6 weeks.


RESULTS
Following unloading for 6 weeks, proximal tibia metaphysis was shown 64.0% decrease in bone mineral content (BMC) and 47.0% decrease in bone mineral density (BMD) in HU group while significant reduced bone lose with 2.7% increase in total BMC and only 9.2% decrease in total BMD in HUES group. Diaphyseal BMD decreased significantly in both HU and HUES group as compared with CC group. There was enhancement of CGRP expression in the DRGs in HUES group.


CONCLUSION
This experimental study proved the proposed concept using electrical stimulation at the DRG for prevention of disuse-induced bone loss in a rat hindlimb suspension model.
['Yuen-Chi Lau|Roy|R|', 'Qian|Xing|X|', 'Po|Kai-Ting|KT|', 'Li|Lu-Ming|LM|', 'Guo|Xia|X|']
D000704:Analysis of Variance D000818:Animals D001835:Body Weight D015519:Bone Density D001847:Bone Diseases D015740:Calcitonin Gene-Related Peptide D004195:Disease Models, Animal D004558:Electric Stimulation D005500:Follow-Up Studies D005727:Ganglia, Spinal D019417:Hindlimb Suspension D008297:Male D051381:Rats D017207:Rats, Sprague-Dawley D013977:Tibia D013997:Time Factors D015898:Tomography Scanners, X-Ray Computed
electrical stimulation Dorsal root ganglion immobilization microgravity disuse osteoporosis