Objective To investigate the synergistic effects of simulated microgravity and noise on the audito‐ry functions and corti organs in rats .Methods A total of 48 healthy rats were randomly divided into 4 groups (n=12):control group (Group A) ,microgravity only group (Group B) ,noise only group (Group C) and microgravity+noise group (Group D) .The microgravity environment was simulated by suspending the posterior limb using Morey-Holton method .The noise exposure was the simulation of the noise environment in spaceship including steady -state noise (72 ± 2) dB SPL and impulse noise up to 160 dB SPL .The control group was kept in normal conditions without any exposure .Auditory brainstem responses (ABRs) ,HE stainings ,immunofluorescence stainings and scanning electron microscopes (SEMs) were tested after 1week and 2 weeks exposure respectively (n=6) .Results The average of ABR threshold shifts of 2 weeks exposure were higher than those of 1 week in each group .Group D showed the highest ABRs (P<0 .01) .The HE stainings showed different degrees of injury in corti organs in all experimental groups ;which Group D being the most serious ,followed by Group C .The results of immunefluorescence in hair cells showed that swelling necrosis was the main damage of cochlear hair cell after 1 week's exposure .The swelling rate of Group D was the highest ,followed by Group C .Nucleus missing in hair cells was observed after 2 weeks'exposure . Group D had the highest missing rate and the main missing of Group B happened in the inner hair cells .SEM showed that the most serious damage of stereociliums in Group D ,followed by Group C ,then Group B .Conclusion The synergistic effects of simulated microgravity and noise lead to significant damage of the auditory function and cochlea Corti organs in rat .

Objective]To study the feasibility of Cartilage engineering using fibrin gel and chondrocyte cell sheets.[Methods]rabbit auricular chondrocytes were isolated and cultured to form cell sheets in flasks. The cell sheets were harvested using cell scrapers,and cut into fragments. The two precursor solutions of Fibrin gel were used to suspend the cell sheet fragments and isolated chondrocytes,and then added into the wells of a 48-well plate to form Gelatinous chondroid disc constructs. After in vitro culture, the constructs were implanted into nude mice. After 8 weeks,the constructs were harvested,and the specimens were evaluated using grossly observing, histological and immunohistochemical observation. [Results]Mature cartilage discs were obtained. The histomorphology of the explanted discs appeared non-uniform cartilaginous tissue comprise of regenerated cartilage islands with different size and irregular shape. Immunohistochemistry staining demonstrated that type II collagen highly expressed in the ECM of the cartilage islands. In 1 of the 8 discs,partial ossification was observed.[Conclusion]Fibrin gel is a favourable carrier. Artificial cartilage with stereochemical structure was constructed via combining the fibrin gel and chondrocyte cell sheets.

OBJECTIVE To investigate the effects of simulated noise-weightlessness combined factors on auditory brainstem response thresholds and the cochlear structure after a medium-long term (2-8 weeks). METHODS Healthy adult rats were randomly divided into male/female experimental and control groups. The male and female experimental groups were exposed to simulated noise-weightlessness environment and exerted impulse noise exposure at the end. Auditory brainstem response (ABR) threshold was recorded at the beginning, the 2nd, 4th and 8th weeks and after impulse noise exposure exerting. The cochlea was also examined by scanning electron microscopy each time after ABR threshold record. RESULTS ABR thresholds in experimental groups after impulse noise exposure were significantly increased (P<0.05). Female experimental group were lower than those of the male experimental group at 2 and 4 weeks (P<0.05). Scanning electron microscope observation showed that the inner and outer hair cell were losing and lodging, and the longer exposed to the compound factors, the heavier pathological changes observed on the cochlear hair cell. CONCLUSION Noise-weightlessness combined factors can cause the morphology and function damage of rat cochlear in medium-long term. The damage of impulse noise was more than steady noise on rat auditory function. Sex differences was also observed. Rat cochlear hair cell pathological changes increased with the exposed time.

Objective: To observe the morphological changes on cochlear hair cells of rats in simulated weightlessness and inboard noise and to investigate the different changes in three turns of hair cells.Methods: Thirty-two healthy SD rats, all males, were randomly divided into four groups: control group, weightlessness group, noise group and weightlessness+noise groups (n=8).Then rats were exposed to-30° head down tilt as simulated weightlessness and inboard noise including steady-state noise which was (72±2) dB SPL and impulse noise up to 160 dB SPL in spaceship environment.The control group was kept in normal condition for 8 weeks.Bilateral auditory brainstem response (ABR) thresholds were tested before and after exposure respectively, and immunofluorescence staining and scanning electron microscopy (SEMs) of basilar membrane were applied after exposure.Results: ABR threshold shifts of each group were higher after exposure.There was difference between ABRs of the experiment groups before and after exposure (P<0.05).IF showed that the inner hair cells (IHCs) missing was the main damage in the basal turn of weightlessness group, the hair cells in the middle turn were swell and in the top turn, the hair cells were not clear.In noise group, the main loss happened in the outer hair cells (OHCs) of the outermost layer.In weightlessness+noise group, the nuclear missing in the basal turn was apparent, and mainly happened at the outermost layer.Meanwhile, the missing of hair cells in the middle turn and top turn was seen at the innermost layer.SEM showed that the cilia in the basal turn of weightlessness group were serious lodging, and occasional absence.Furthermore, the basal cilia in noise group became lodged and absent, and the other two turns were seriously missing.And in weightlessness+noise group, the cilia missing in the basal turn was apparently seen.The damage degree of the four groups: weightlessness+noise group>noise group>weightlessness group>control group and the damage degree of the four turns of hair cells: basal turn>mid turn>top turn.Conclusion: The rats exposed to the above environment for 2 weeks displayed obvious changes in cochlea morphology, and the weightlessness+noise group had the most obvious damage.

BACKGROUND:To seek for ideal scaffold materials is still an important task for cartilage tissue engineering.OBJECTIVE:To investigate the application of the AviteneTM microfibrillar collagen hemostat sponge in cartilage tissue engineering.METHODS:Rabbit auricular cartilage was harvested via surgical operation,and primary chondrocytes were isolated and amplified.Microfibrillar collagen hemostat sponge was cut into small bricks.The passage 2 chondrocytes were suspended and seeded onto the spongy bricks.After 1 week of in vitro culture,the constructs were then implanted into nude mice.After 8 weeks,the specimens were collected and evaluated using gross,histological and immunohistochamical observation.RESULTS AND CONCLUSION:During the cell seeding,the scaffold maintained its dimensions.No shrinkage was observed when the cell suspension was added.There was no considerable change in dimensions during the 1-week in vitro culture and at 8 weeks after implantation in nude mice.At 8 weeks post-implantation,mature cartilage blocks were harvested,which were white,translucent,and flexible.Histologically,the constructs appeared to have typical mature cartilaginous tissues,with robust extracellular matrix secretion,in which the microfibrillar collagen was incompletely degraded.We conclude that the microfibrillar collagen is a favorable scaffold material for cartilage tissue engineering.

BACKGROUND:The cell-sheet technology, based on a temperature-responsive culture, has been drawing more and more attention;however, the temperature-responsive culture dish is quite expensive. Therefore, it is imperative to develop a substitutive technique.OBJECTIVE: To study the feasibility of cell-sheet ulturing using common culture dish, and investigate the chondrogenesis of the cell sheet. METHODS: A piece of nasal septal cartilage was adopted from a patient with deviation of nasal septum to extract primary chondrocytes that were then cultured and amplified. The passage 3 chondrocytes were used to construct ell sheets. Monolayer cell sheet was formed by intensive culturing and allowing the extracellular matrix secretion. Bilayer cell sheet was constructed by seeding passage 2 chondrocytes on the monolayer cell sheet. The cell sheets were harvested using cell scraper, their properties were investigated prior to plantation into nude mice to construct the tissue-engineered cartilage. RESULTS AND CONCLUSION: Both bilayer and monolayer cell sheets with soft tremellose structures showed no significant difference through naked eyes. The newly harvested cell sheets appeared to have good fluidity and gelation. Eight weeks after mplantation into the nude mice, mature cartilage blocks were obtained. Histologically, the cell sheets were thin films composed by layered chondrocytes and extracellular matrix. Glycosaminoglycan formation and type Ⅱ collagen expressions were observed in the cell sheets cultured in vitro. The explanted samples exhibited ature cartilaginous tissue at 8 weeks after implantation. Biochemical analysis showed that the DNA contents of the neocartilages were higher than those of native human costal cartilage, while the contents of glycosaminoglycan and hydroxyproline were similar to native human nasal septal cartilage. To conclude, the hondrocyte cell sheets are likely to be constructed and harvested successfully using common culture dish, and the cell sheets exhibit favourable chondrogenesis.

BACKGROUND:Rapid prototyping technique has been recently applied in the medical reconstruction and al ows the production of individual implant for patients with tissue defects, achieving an accurate repair.
OBJECTIVE:To repair discontinuous mandibular defects in dogs using rapid prototyped titanium plate in combination with autologous cancellous bone graft.
METHODS:Nine hybrid canines were used, and the skul was scanned using spiral CT. Then CT data were used to construct three-dimensional digital model, in which virtual partial mandibulectomy was performed, and an individualized bone-grafting plate was designed. A titanium plate was manufactured using rapid prototyping and titanium casting. Animal experiment was then performed. A 40-mm discontinuous defect in the right mandibular body was created in the involved dogs. The defect was restored immediately using the customized plate in combination with autologous cancellous iliac blocks. Sequential radionuclide bone imaging, biomechanical testing, three-dimensional microcomputed tomographic scanning, radiology and histological examination were used to evaluate the turnover of the grafts.
RESULTS AND CONCLUSION:A symmetric mandible was reconstructed using the rapid prototyped grafting plate. The grafted bone survived and got corticalized, while a fibrous intermedium was found between the bone graft and the plate. In the reconstruction of mandibular defects, optimal functional and aesthetic outcomes could be achieved using the rapid prototyped grafting plates.

Objective To investigate the effects of intense low frequency noise on expression of caspase -3 in bama pigs ,and observe the death of cochlea hair cell .Methods 8 bama pigs were randomly divided into a normal control group(2 pigs) and experimental groups(6 pigs) .Auditory brainstem responses(ABR) were tested before the experiment .The control group was the same as the experimental groups except noise exposure .The experimental group was randomly divided into immediate group ,36 h group ,and 84 h group(2 pigs per group) .They were ex-posed to intense low frequency noise at 142 dB of 50 Hz for 5 min according to the three time points .ABR were test-ed again before the cochlea were collected at different time points .The expression of caspase -3 was studied through immunohistochemistry and immunofluorescence ,hair cell loss rate by counting to determine cell death .Results The average ABR threshold of 8 bama pigs(16 ears) before the exposure was 61 .25 ± 10 .72 dB nHL .ABR thresh-olds were not elicited after exposure to the noise .Different parts of bama pigs showed positive expression of caspase -3 in two ways .As time prolonged after exposure ,the positive expression of caspase -3 gradually weakened .The im-mediate group and 36 h group ,compared with the control group ,showed the apparent misplace of three out hair cells in the arrangement and levels .The 84 h group through immunofluorescence lost out hair cells ,and only inner hair cells were visible .Conclusion ABR thresholds were elevated after noise exposure .The procedure of hair cell nucleus damage and caspase-3 expression is different ,and the noise can induce opening apoptotic program of spiral ganglion .

OBJECTIVE: To Study the clinical features of congenital microtia and atresia . To evaluate the methods and results of the same microtia surgery, ear canal and middle ear reconstruction. METHOD: Statistically analysis of the data of the hospitalization microtia 62 ears of 58 cases of patient in our department from January 2005 to October 2010 waw conducted. These patients with congenital ear malformations are associated with aural atresia, ossicular chain abnormalities, severe conduction Deafness. All patients received preoperative temporal bone CT examination and reconstruction, hearing examination. Operation was given in two phases, first operation aim to form a line of ear, ear canal reconstruction, ear reconstruction, the second one aim to line of ear skin graft, cranial angle of the ear reconstruction. The preoperative and postoperative data were retrospectively analyzed. RESULT: The auricle plus external auditory canal, middle ear reconstruction came out with a good shape of the ear and the ear canal in close proximity to the normal population. Most patients' hearing were improved after surgery. CONCLUSION Surgeries of patients with congenital ear malformations and aural atresia should be carefully designed according to the three-dimensional reconstruction of multislice spiral CT reconstruction, which can provide information about surgery approach and middle ear abnormality. The whole ear shape and hearing ear after reconstruction are improved after the surgery.
Adolescent ; Angioplasty ; Congenital Microtia ; surgery ; Ear ; Ear Auricle ; abnormalities ; surgery ; Ear Canal ; abnormalities ; surgery ; Ear, External ; abnormalities ; surgery ; Hearing ; Hearing Loss ; surgery ; Humans ; Reconstructive Surgical Procedures ; methods ; Retrospective Studies ; Skin Transplantation ; Tomography, X-Ray Computed

Objective To investigate the application and the effects of individualized hollow resin plugs in the prevention of external auditory canal stenosis after canaloplasty of external auditory meatus for microtia patients . Methods The clinical data of 65 patients (68 ears) with microtia and aural atresia hospitalized in our department from January ,2006 to December ,2015 were summarized .Otoplasty of external ears and canaloplasty of external auditory meatus were operated on all patients under general anesthesia .Thigh flap transplantation was lined in the bony canal .One month later ,individualized hollow resin plugs were made and worn for 6 to 12 months ,and fol-lowed up for 1～2 years .Results The shapes of the reconstructed auricles were satisfactory .Sixty-four ears with wide external auditory canal openings were recorded in 68 ears .Preoperative hearing was 70 .45 ± 5 .5 dB HL ,and postoperative hearing was 55 .55 ± 5 .2 dB HL .Their hearing was not affected .External auditory canal restenosis occurred in 4 ears .Conclusion The individualized hollow resin plugs do not affect the hearing in use ,and can effec-tively prevent the restenosis of the external auditory canal after microtia reconstruction .