Morphological differences in innervation between mucous glands and serous glands: A quantitative histological study using the sublingual glands of elderly humans

Conclusion: In the sublingual gland, the serous lobule usually carried a higher density of NSE-positive nerve elements than the mucous lobule, whereas the mucous acinus in the mucous lobule was larger than the serous acinus in the serous lobule. Objectives: To demonstrate quantitative differences in nerve elements between the mucous and serous lobules of sublingual glands. Methods: This study investigated using specimens from 14 donated cadavers (mean age = 78 years). Since immunohistochemistry for neuron-specific enolase (NSE) stains all nerves in addition to other mesenchymal cells possibly of nerve origin, the present quantitative evaluation was based on NSE-positive areas per visual field under a ×20 objective lens (0.6 × 0.45 mm when printed). Results: In mucous lobules, the areas occupied by NSE-positive nerve elements ranged from 5798-16,541 μm² (mean ± SD = 9280 ± 2584 μm²). In contrast, the corresponding areas in serous lobules ranged from 7853-23,540 μm² (mean ± SD = 13,520 ± 4351 μm²). The difference in NSE-positive areas was statistically significant (p = 0.0022). However, the mucous acinus in the mucous lobule was 2-times larger than the serous acinus in the serous lobule (2474 ± 1477 μm² vs 1119 ± 632 μm²).