ABSTRACT
Objective To investigate the effect of intense low frequency noise on the different hearing functions and hair cell damage in bama pigs.Methods Thirteen bama pigs were randomly divided into a normal control group (3 pigs) and an experimental group (10 pigs).The pigs in experimental group were randomly divided into 50 Hz subgroup (5 pigs) and 70 Hz subgroup (5 pigs).The 50 Hz subgroup was exposed to intense low frequency noise at 167～170 dB SPL,50 Hz for 30 min,and the 70 Hz subgroup was exposed to intense low frequency noise at 164 dB SPL,70 Hz for 30 min.Auditory brainstem response(ABR) and distortion product otoacoustic emission (DPOAE) were performed before and after noise exposure.The cochlear were collected and the inner ear morphology changes were studied.Results Before the experiment,the ABR threshold of the pig was 20～50 dB SPL,and the average of 50 Hz group was 33.5±9.4 dB SPL,the average of the 70 Hz group was 34.0±4.6 dB SPL.The level of the above 3 000 Hz DPOAE could be elicited.But they were not elicited after the exposure to the noise.The inner ear structures were damaged.The DAPI showed hair cell missing.Conclusion ABR and DPOAE were elevated after noise exposure.The auditory system of bama pigs had irreversible damages.Hair cells damaged were given priority to with necrosis,and the higher the level of intense low frequency noise,the more serious the damage to the hair cell.
ABSTRACT
To establish a platform to monitor the immune rejection after abdominal aortic patch suture in a xenotransplantation model.Methods The carotid was excised from wild-type Bama pigs,cut into 2.5 cmx 1.0 cm pieces in shuttle shape and subsequently sutured to the abdominal aorta of cynomolgus monkeys.No immunosuppressive agent was administered.General conditions of the recipient monkeys were observed.The morphological changes of the graft artery were assessed by pathological examination at postoperative 1 year.Before and 7,14,28 and 49 d after surgery,the blood samples were collected from the recipient monkeys.The serum levels of IgM and IgG antibodies were quantitatively measured by the red blood cell and peripheral blood mononuclear cell (PBMC) from Bama pigs.The quantity of lymphocytes in the recipient monkeys was detected by routine blood test and flow cytometry.Results All 3 monkeys undergoing transplantation survived well.At postoperative 1 year,the lateral tissues of the vascular wall at the artery graft were seen in dark red color.Hematoxylin-eosin (HE) staining revealed a large quantity of red blood cell and platelet deposition,accompanied with lymphocyte infiltration.Using porcine red blood cell and PBMC as target cells,the serum levels of anti-pig IgM and IgG antibodies peaked at postoperative 28 d,and slightly declined at postoperative 49 d.The quantity of lymphocytes and T cell subset also peaked at postoperative 28 d and began to decrease at postoperative 49 d.Conclusions Artery patch suture is a simple and reliable xenotransplantation model.The recipients can maintain normal physiological state without the use of immunosuppressive agents.The grafts can effectively activate the immune system of the recipients,induce the production of anti-pig antibodies and provoke cellular immune rejection.Therefore,this model can be utilized to monitor the immune rejection throughout the xenotransplantation process.