Cystathionine gamma lyase aggravates orthodontic root resorption in mice

This study aimed to determine the contribution of cystathionine gamma lyase (CSE) to physiological and orthodontic root resorption in mice.

Mice genetically deficient in the CSE (CSE^-/-), the dominant hydrogen sulfide (H₂S)-generating enzyme in osteoclast were used in this study. Physiological and orthodontic root resorption was assessed with micro computed tomography (micro-CT) and scanning electron microscopy (SEM) in the mice at the age of 8-, 26-, and 52-week and in 8-week old mice following 1-, 2-, and 3-week orthodontic treatment, respectively. Hematoxylin and eosin (HE) and tartrate-resistant acid phosphatase (TRAP) staining were used for further determination of root resorption and the number of osteoclasts. The receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) level in surrounding alveolar bone of the maxillary first molar after 2-week orthodontic treatment was measured by reverse transcription polymerase chain reaction (RT-PCR).

Root resorption lacunae (RRL) gradually and significantly increased with age in wild type (WT) and CSE^-/- mice. The CSE^-/- showed less RRL compared with the WT group. At each time point of orthodontic treatment, the CSE^-/- group had less RRL and osteoclasts than the WT group. The orthodontically induced RANKL/OPG mRNA expression in the periodontal tissue in the CSE^-/- group was lower than that in the WT group.

CSE contributes significantly to physiological and orthodontic root resorption.