5 ala powder

The parathyroid glands of 28 Sprague-Dawley (SD) male rats, (~ 8 weeks of age, 260–350 g body weight) were identified by 5-aminolevulinic acid hydrochloride (5-ALA) photosensitization. In brief, 5-ALA powder (Sigma-Aldrich, USA) was suspended in a 0.5 ml of 0.9% sodium chloride solution and intraperitoneally injected (500 mg/kg) into the rats. Animals were anesthetized by inhaled isoflurane gas machine 2 h later, and a vertical skin incision was made at the midline of the neck. Muscle was dissected to the trachea and thyroid gland, and the parathyroid glands were visualized under the illumination of xenon light source (380–440 nm) and an ultraviolet filter to detect fluorescence at the 635 nm wavelength. The pair of parathyroid glands exhibited red fluorescence anterolateral to the thyroid gland. Bilateral parathyroidectomy was performed, and the rats were sacrificed with 4% pentobarbital. All the experiments were approved by the Ethics Committee for Animal Experiments of Tongji Medical College and Wuhan University.

Parathyroid glands in all PTX groups were identified and removed according to the 5-ALA fluorescent-identification method. [11 (link)] Briefly, 5-ALA powder (Sigma-Aldrich Korea, Yongin, Korea) was suspended in a 0.5 mL of 0.9% sodium chloride solution. The resultant 5-ALA solution was administered (500 mg/kg) by intraperitoneal injection to the PTX and SHAM groups. All animals were kept under subdued light for 2 hours to prevent phototoxicity. After 2 hours, animals were anesthetized by intraperitoneal injection of Zoletile (Virbac Korea, Seoul, Korea) and xylazine chloride (Bayer Korea, Seoul, Korea) (1:1 mix, 0.1 mL/100 g). A vertical skin incision was made at the midline of the neck, and muscles were dissected until the trachea and thyroid gland were exposed. The red fluorescent parathyroid glands were detected under illumination of a xenon light (380–440 nm) source with an ultraviolet filter that was designed to detect fluorescence emission at 635 nm. Both parathyroid glands were removed in the PTX groups using a cold knife while the glands were retained in the SHAM group. Hemostasis was performed by gauze compression and bipolar cauterization. The skin incision was sutured with non-absorbable 4–0 Ethilon^® (Johnson & Johnson, New Brunswick, NJ, USA).