Structural and functional changes of pharyngeal muscle in rats with altitude hypoxia-induced obstructive sleep apnea syndrome
- Author:
Bing LI
1
Author Information
1. Department of Respiratory Diseases
- Publication Type:Journal Article
- From:
Academic Journal of Second Military Medical University
2006;27(4):396-399
- CountryChina
- Language:Chinese
-
Abstract:
Objective: To observe the changes ot structure and function of pharyngeal muscle in SD rats with altitude hypoxia induced obstructive sleep apnea syndrome (OSAS),in an attempt to investigate the remodeling of pharyngeal space and the possible biomechanical mechanism of OSAS. Methods: Twenty-four SD rats(12 male and 12 female) were randomly assigned to 4 groups with 6 rats in each group. Rats in group A and B were male and those in group C and D were female. Rats in group A and C were placed in altitude chamber and treated with altitude hypoxia 6 h per day for 22 days. The pressure in the chamber was 53.9 kPa with an oxygen concentration of 10.0%-11.2%. Rats in group B and D, serving as controls, received no treatment. All rats were sacrificed on the 23rd day. The open-angle and the inside diameter of rats' pharyngeal-ring and the pathology of pharyngeal tissues were examined in all rats. Results: The open-angles of rats' pharyngeal-ring of group A, B, C and D were (55±24)°, (15±8)°, (38±20)°, and (35±15)°, respectively; and the inside diameters of the pharyngeal-ring(cm) were 0.4±0.2, 0.2±0.1, 0.3±0.1, and 0.3±0.1, respectively. The open-angle and the inside diameter of rats' pharyngeal-ring in group A were significantly higher (P<0.05) than those of group B, C, and D, with no significant difference found between group C and D. Microscopic findings showed that, compared with group B, the muscle fibers of group A were fatter and were arranged disorderly, with unclear transverse striation, dropsical and congestive subcutaneous tissues infiltrated with inflammatory cells. Local unclear transverse striation of muscle fiber was seen in group C; the muscle fibers in group B and D were orderly arranged and no inflammatory cells were seen subcutaneously. Electron microscope showed disarranged muscle fibers with dissolved myofilament, disturbance and disappearance of the Z line in part of muscle fibers, expanded sarcoplasmic reticulum, and slightly condensed muscle cell nuclei. Local myofilament dissolving was found in group C. Conclusion: Twenty-two days' intermittent altitude hypoxia can induce OSAS in SD rats through changing the structure and function of pharyngeal muscle and remodeling the pharyngeal space.
