Effects of Exogenous Interleukin-9 on the Growth, Proliferation and Activity of Interstitial Cells of Cajal Cultured in vitro.

OBJECTIVES

To evaluate the role of exogenous interleukin-9 (IL-9) in the growth, proliferation and activity of interstitial cells of Cajal (ICCs) cultured in vitro, and to assess its role in maintaining the functions of ICCs.

METHODS

ICCs of murine gastric antrum were isolated and cultured in vitro. ICCs were identified with c-Kit and ANO1 immunofluorescent antibodies. Both fluorescence microscope and confocal microscopy were used to observe the effects of IL-9 on the growth, proliferation and activity of ICCs in cultured in vitro. ICCs were loaded with fluorescence probe Fluo-3/AM and the fluorescence of intracellular calcium concentration ([Ca2+]i) was measured by confocal microscopy. The effects of exogenous IL-9 on the sulfated cholecystokinin octapeptide (CCK-8S)-evoked [Ca2+]i elevation were observed by confocal microscopy.

RESULTS

Immunofluorescence results confirmed the successful separation and culture of ICCs in vitro. IL-9 in concentrations ranging from 0.02 to 1 μg/ml promoted the growth, proliferation and activity of ICCs in culture, and ICCs grew best with 0.5 mg/ml of IL-9. The presence of IL-9 could significantly increase the CCK-8S-evoked [Ca2+]i oscillation, which is probably caused by facilitating the maintenance of the functions of ICCs under suitable conditions for culture.

CONCLUSION

IL-9 could promote the growth, proliferation and activity of ICCs, reinforce the CCK-8S-induced [Ca2+]i increment in ICCs, and facilitate the maintenance of the functions of ICCs under suitable culture condition.