| Barotitis media (BM) is still the most common otitis disorder among flying personnel and passengers. The proportion of BM in otolaryngologic illness resulting in permanent grounding is higher. With the increase in hyperbaric oxygen therapy (HBO), the incidence of BM has risen. Research shows that BM is closely related to the function of eustachian tube (ET).In resent years, a surface active substance lining the animal and human eustachian tube with surface lowering properties has been demonstrated. It facilitates the opening of the ET and helps to aerate the middle ear, and it is of importance to maintain the function of ET. Thereby increasing attention has been paid to the surfactant concerning to its effect on the function of ET and BM. However, there is scarcely report on the mechanism of its secretion and metabolism, especially its effect on prevention and treatment of BM.This investigation included: Observe the distribution of secretory cells in mucosa of the guinea pig eustachian tube by transmission electronic microscope (TEM); Isoprenaline hydrochloride was given i.v. to guinea pig, and the contents of phospholipid and protein in eustachian tube surfactant in normal control and post injection groups were analyzed and compared by thehigh performance liquid chromatographty (HPLC) andthe spectrophotometry;Guniea pigs were undertaken the flight simulated test in the hypobaric cabin to establish the barotitis media modeI;The middle ear pressure necessary to force the eustachian tube to open(opening pressure level, POL) in both normal and barotitis media under flushing of middle ear with natrue ETS, artificial ETS and saline were tested; BM models were treated with artificial ETS, to provide a theoretical basis for prevention and treatment of the barotitis media with ETS.Result1. Ultrastructural Observation of Secretory Cells in Mucosa of the Guinea Pig Eustachian Tube Three types of secretory cells were identified, the dark granulated cells were predominant in the tympanic orifice; the mixed cells were major in the isthmus portion, while the light cells were remarkable in the pharyngeal orifice. Surfactant-like lamellar bodies were found in secretory cells of the eustachian tube mucosa.2. Effect of Isoproterenol on Secretion of Competent in the Eustachian Tube Surfactant The content (jag/two ears) and percentage of phospholipid, the content(jag/two ears) of protein in Eustachian tube surfactant were as follow: In normal control, phosphatidylcholine (PC) was 22.448 ?7.432(14.27%) ; phosphatidylserrine ( PS ) was 0.354 ?0.178(0.23%) : phosphatidylethanolamine ( PE ) was 71.229 ?24.343(45.30%); phosphatidylinositol (PI) was 63.213 + 12.902(40.20%); In comparison, in post injection: PC was 57.842 + 25.639 (26.86%); PS was 1.103+0.471(0.51%); PEwasl24.000 + 27.848 (57.58%); PI was 32.417 + 11.936(15.05%); Protien: in normal control: 6.015?1.749, in post injection: 8.609?.364.3. Experiment study on the animal model of barotitis mediaThe hearing threshold of twenty nine ears was elevated with a predominance of low frequency. The major pathologic change was dominated by serous and fibrinous exudation in middle ear.4. The effect of surfactant on eustachian tube function in a guniea pig model of barotitis media The average POL in the normal group was 5.96+1.63 kPa. The average POL in the BM group increased to 11.91?1.87kPa. In BM group: Using artificial ETS reduced the POL from 11.91 ?I.87kPa to 6.67?.72kPa; Using nature ETS, the POL decreased from11.98.93kPa to 6.11 ?1.69kPa. The differences between ETS groups and saline group were statistically significant, while there are not significant difference between artificial ETS group and nature ETS group. In control group, the POL was decreased from 11.91 ?1.82kPa to 11.73 + 1.62kP , not significantly change. Artificial Phospholipid group significantly reduced the POL from 11.86+1.57 kPa to 8.61 ?.88 IcPa. In comparision there is a relative lessen in the active with the artificial ETS group.5. Th... |
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