抄録
α-isoproterenol was administrated to study its effect on the soleus and tibialis anterior muscles after sciatic nerve crush injury.
ICR mice were divided into 3 groups; nerve crush injury (NC group), α-isoproterenol administration after nerve crush injury (NC・IPR group) and control (CNT group). At three weeks following crush injury, soleus and tibialis anterior muscles were sampled for light and electron microscopic observation. Irregular banding pattern of myofilaments was seen in NC group. Administration of α-isoproterenol induced prevention of muscular atrophy in all muscles in NC group. Notably, the size of cross-sectional area in the red muscle dominant soleus muscle in NC・IPR group was significantly larger than that in NC group. However, there was no significant difference in the white muscle dominant tibialis anterior muscle. The result suggested a substantial effect of α-isoproterenol on red muscles in prevention of muscular atrophy after nerve crush injury.
Investigated also was the influence of α-isoproterenol on the submandibular gland in Wistar rats in addition to the same mice as above. Electron density of secretory granules in the granular duct cells differed between α-isoproterenol administrated group and control group. Whereas control group showed many secretory granules equally with high electron density, α-isoproterenol administrated group showed variability in electron density among secretory granules with reduction in the number of secretory granules with high electron density. GS-II displayed little reactivity in secretory granules of the granular duct in both groups, while WGA induced intensive effect in the granules with high electron density in the both groups. These results indicated that lectin staining in the granular ducts derived from sialic acid within the electron-dense granules. Hypertrophy of acinar cells of the submandibular gland was observed in both species. The rat acinar cells developed peculiar lamellar inclusions in the secretory granules, which exhibited WGA reactivity.
In the application of α-isoproterenol for prevention muscular atrophy, one should be consider its side effects on the submandibular gland as observed in the present study.
