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Serotonin receptor agonist quipazine promotes proliferation and apoptosis of human hepatocyte strain of L-02 strain.

BACKGROUND
Liver disease is commonly seen in the clinic and its pathological characteristic is combined hepatocellular death and apoptosis. Promoting hepatocyte regeneration is one of the main methods of treating liver disease. Serotonin (5-HT) is an important compound which participates in various life process, and 95% of it is carried by platelets in the blood. A recent finding showed that platelet-derived serotonin is the key factor in liver regeneration, which fails without serotonin. This study aimed to investigate the effects of quipazine, a selective 5-HT receptor agonist, on proliferation and apoptosis in the human hepatocyte strain L-02.


METHODS
L-02 cells were cultured in medium with 5-HT and quipazine, and samples were collected at 24, 48, and 72 hours. The methyl thiazolyl tetrazolium (MTT) method was used to test viability, flow cytometry to assess the cell cycle, the Annexin-V/PI method to evaluate apoptosis, and immunohistochemistry to detect proliferating cell nuclear antigen (PCNA).


RESULTS
Compared with the control group, the viability of L-02 cells was improved in the 10, 50, and 250 microg/ml quipazine groups (P<0.05); the percentage of S-phase and PCNA-positive cells were increased in the 2, 10, 50, and 250 microg/ml quipazine groups (P>0.05); and no difference in the percentage of apoptotic cells was found between the 50 microg/ml quipazine and control groups (P>0.05).


CONCLUSION
Quipazine improves proliferation of a human hepatocyte strain in vitro, and this is not based on the inhibition of apoptosis.