BACKGROUND: Hepatocyte/polymer interface with good biocompatibility is the key factor in bioreactor design andconstruction, however, bioreactor used in the clinical practice currently is not an ideal one.OBJECTIVE: To establish human hepatocyte compatible polypropylene interface and to lay a foundation for establishingbioartificial liver reactor with polypropylene hollow fiber.DESIGN, TIME AND SETTING: The comparative observation, cell compatibility experiment was performed betweenFebruary and October 2003 at Shanghai Jiao Tong University, Shanghai, China.MATERIALS: Polypropylene Photochemical graft polymerization modification technique was used to graft hydrophilicacrylamide groups on the surface of polypropylene membrane by chemical bonds to form modified polypropylenemembrane.METHODS: L02 human hepatoeytes were seeded on polypropylene membrane, modified polypropylene membrane andpolystyrene membrane, and polystyrene membrane was used as normal control.MAIN OUTCOME MEASURES: Static water contact angle of polypropylene membrane before and after graftmodification; morphology, adherent rate and proliferation activity of L02 human hepatocytes on different material surfaces.RESULTS: Static water contact angle after polypropylene membrane graft modification was smaller than that before graftmodification (P < 0.05). The adherent rate of L02 human hepatocytes on the surface of modified polypropylene membranewas 0, and the proliferation activity of them, which grew as spherical aggregates, was markedly higher than that of cells onpolystyrene membrane and polypropylene membrane without graft modification.CONCLUSION: Grafting polyacrylamide on the surface of polypropylene can establish good interface of L02 humanhepatocytes/polypropylene and form hepatocyte spherical aggregates through simple static culture.

Objective: The aging model of guinea pigs induced by D-galactose was set up to investigate the changes of BK_Ca expression and function on cochlear pericytes and their relationship with age-related hearing loss. Methods: Thirty healthy 8-week-old guinea pigs were randomly divided into three groups, with 10 in each group: D-galactose aging model group, subcutaneous injection of D-galactose (500 mg/kg) daily for 6 weeks; saline control group, the same amount of saline was injected into the neck of the aging model group for 6 weeks; the blank control group, no treatment was performed. The threshold of auditory brainstem response (ABR) was detected. The content of BK_Ca in the perivascular cells of the guinea pig cochlear cells was detected by immunofluorescence technique. The changes of peripheral current density and BK_Ca current were detected by patch clamp technique. The data were analyzed by GraphPad Prism software. Results: Compared with the saline group and the control group, the ABR threshold and the amplitude of the wave I were significantly decreased in the aging model group, and the difference was statistically significant (P<0.01). Compared with the control group, the expression of BK_Ca in the vascular pericytes of guinea pigs in the aging model group was significantly reduced (1.00±0.08 vs 0.27±0.03,the difference was statistically significant P<0.01), and the cell current density and BK_Ca net current value were also significantly reduced with statistically significant (P<0.01). Conclusions D-galactose can successfully induce guinea pig aging model, in which BK_Ca expression decreases and net current value decreases in pericytes of cochlear striavascularis, and changes in BK_Ca expression and function may be related to age-related hearing loss.