Regeneration of taste through sonic hedgehog upregulation by photobiomodulation

This study investigated photobiomodulation (PBM) effects in Sonic hedgehog (Shh) signaling as a potential approach to taste preservation and regeneration. Primary taste cell (TC) cultures were treated with Shh antagonist vismodegib and irradiated using a continuous wave type 630 nm light-emitting diode (10 mW/cm² ) array, with single or multiple doses of 30 J/cm² to determine dose inducing significant upregulation effect. Shh, Ptch, Smo, and Gli1 were significantly upregulated at 120 J/cm² , used as the minimum dose in vivo. Vismodegib was administered via daily oral gavage for 21 days (30 mg/kg) to induce Shh inhibition in the tongue of rat animal models resulting in taste bud damage and taste dysfunction. PBM treatment using a 630 nm laser (3 W/cm² ) at a radiant exposure of 120 J/cm² (24 J/cm²  × 5) successfully upregulated the Shh protein expression, regenerated taste buds, and recovered taste function.