Treatment of Neural Anosmia by Topical Application of Basic Fibroblast Growth Factor–Gelatin Hydrogel in the Nasal Cavity

Abstract

IMPORTANCE: A new treatment of neural anosmia. OBJECTIVE: To investigate the effects of basic fibroblast growth factor (bFGF)-gelatin hydrogel on recovery of neural anosmia in mice. DESIGN: Anosmia was induced by intraperitoneal injection of 3-methylindole, 200 mg/kg. One week later, the animals underwent 1 of the following 3 procedures bilaterally: (1) group A: single-shot intranasal drip infusion of phosphate-buffered saline, (2) group B: single-shot intranasal drip infusion of bFGF, and (3) group C: placement of bFGF-gelatin hydrogel in the nasal cavity. The olfactory function of the animal was evaluated by the odor-detection test (ODT) 2 and 4 weeks later. Following the testing, the animal was killed, the thickness of the olfactory epithelium was measured, and the number of olfactory marker protein (OMP)-positive cells was counted. SETTING: Research installation. PARTICIPANTS: Mice. INTERVENTION: The placement of bFGF-gelatin hydrogel in the nasal cavity. MAIN OUTCOMES AND MEASURES: An ODT, thickness of olfactory epithelium, the number of OMP-positive cells RESULTS: The ODT proved that neural anosmia recovered in group C but not in groups A and B. Histologically, olfactory epithelium became thicker and the number of OMP-positive cells increased in group C, while such functional and histologic recovery was poor in groups A and B. These findings suggested that placement of bFGF-gelatin hydrogel in the nasal cavity was an efficient way to facilitate recovery of neural anosmia. CONCLUSIONS AND RELEVANCE: As a gelatin hydrogel degrades slowly in the body, bFGF is gradually released around the site of the lesion; thus, it constantly exerts its effects on neural regeneration.