MRNA Expressions Of Hyaluronan Synthase And Nucleotide-binding Proteins In The Epithelial Cells Of Endolymphatic Sac And The Effects Of PGE₂ On Its Alterations.

The endolymphatic sac (ES) is believed to absorb endolymph and have a secretory capacity for hyaluronan(HA), This dual function of absorption and secretion is suggested to be closely related to the regulation of inner ear fluid volume, pressure and electrolyte balance. In order to elucidate the regulatory function, ES epithelial cells were isolated from the ES of guinea pigs by enzymatic and mechanical dissociation, cultured and observed in artificial perilymph for 12days under the inverted microscope, and identified with Laser confocus microscope. The isolated ES epithelial cells were classified into light and dark cells by their characteristic morphology (mainly by the shape of the nucleus and cell body) in general, while some cells were difficult to be distinguished in some cases. The present study has established the isolating procedure and culture method for ES epithelial cells.The expressions of Na⁺.K^- -ATPase β subunit isoforms were detected in the ES of guinea pigs with cryosection and hybridization in situ. β₂ mRNA was strongly expressed in the epithelial cells of ES, and coupled with weak expression of β₁ , mRNA. Coexpression of different β subunit isoforms Na⁺,K⁺-ATPase in the ES of guinea pigs reflect its characteristics which are different from that of kidney and colon in ion and fluid transporting.The oligonucleotide probe of hyaluronan synthase was designed and synthesized, the mRNA expressions of hyaluronan synthase in the epithelial cells of ES and renal tubules were detected with hybridization in situ. mRNA of hyaluronan synthases were strongly expressed in some cells of ES and renal tubules. It is confirmed that a dual regulatory system for hyaluronan...