Dantrolene counteracts the masseter muscle damage induced by artificial occlusal wear: studies in a rat model.
In previous studies, we showed that the introduction of occlusal alterations to rats results in masseter muscle abnormalities. Here, we investigate whether administration of the muscle relaxant dantrolene to rats with occlusal alteration could counteract the occurrence of such abnormalities. Rats underwent unilateral amputation of molar cusps to cause malocclusion. Some rats received dantrolene (10 mg/kg/day subcutaneously). The masseter muscles ipsilateral to the amputated molars were excised 26 days later. Sham-operated rats were used as controls. The tissue samples were studied by light and electron microscopy and morphometry. Moreover, tissue Ca2+ content, an index of muscle injury, was determined. In the absence of dantrolene, occlusal alteration leads to microvessel constriction, morphologic damage of masseter muscle fibers and blood capillaries, and elevation of tissue Ca2+ content. These changes were nearly abrogated by dantrolene, thus supporting it as a possible new therapeutic tool for the treatment of malocclusion-induced muscle diseases.
Bani
D
D
Department of Anatomy, Histology and Forensic Medicine, Section of Histology, University of Florence, Italy. bani@unifi.it
Bergamini
M
M
D000704:Analysis of Variance; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002199:Capillary Permeability / Q000187:drug effects; D003620:Dantrolene / Q000494:pharmacology* / Q000627:therapeutic use; D003769:Dental Occlusion, Traumatic / Q000150:complications*; D008297:Male; D008406:Masseter Muscle / Q000098:blood supply / Q000187:drug effects* / Q000293:injuries*; D009125:Muscle Relaxants, Central / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D018709:Statistics, Nonparametric; D013706:Temporomandibular Joint Dysfunction Syndrome / Q000209:etiology / Q000517:prevention & control; D014664:Vasodilation / Q000187:drug effects
D009125:Muscle Relaxants, Central; D003620:Dantrolene; D002118:Calcium