ABSTRACT
Objective To observe the inhibitory effect of pyridoxine hydrochloride (PN) combined with common chemotherapeutics on mice hepatoma cells H22 in vitro. Methods MTT assay was used to determine the effects of PN in combination with 10 different antineoplastic agents on H22 cells, and immuno-histochemistry was used to observe the distribution of PN in H22 cells and morphologic changes of the cells before and after PN treatment. Results After 24 hours incubation with 5 mmol/L PN, the treated cells expanded apparently with nucleus chipping. PN entered the tumor cell and was mainly condensed in cytoplasma and H22 cells were sensitive to PN. When administered concomitantly with chemotherapic agents, most of the combinations showed antagonistic effects while a few of the combinations were additive. For instance, doxorubicin (ADM) used in combination with PN inhibited cell proliferation with an IR value (IR=0.63) much lower than ADM alone (IR=0.71, P0.9), and the IR value (IR=0.60) in combined group was higher than that (IR=0.40) in ICTX group (P<0.05). Conclusion PN treatment could increase the intracellular PLP level and result in growth inhibition and cell death, and combined administration of PN and ICTX might be a potential method to improve efficacy and to reduce toxic effects while a co-administration of PN and ADM should be avoided.
ABSTRACT
This paper is to report the exploration of the activation of Rho/ROCK signal pathway in 5-HT-induced proliferation of rat pulmonary artery smooth muscle cells (PASMCs) and the inhibitory effect of m-Nis on this pathway. PASMCs were cultured with the explant technique. MTT assay was used to explore the proliferation of PASMCs after 5-HT treated for different time and the intervening effect of m-Nis. RT-PCR and Western blot were used respectively to explore the mRNA expression of RhoA, ROCK1 and the protein expression of p-MYPT1 in 5-HT-treated PASMCs and intervening effect of m-Nis. The results of MTT assay suggested that 5-HT (1 µmol · L(-1)) treatment for 12-72 h significantly induced the proliferation of rat PASMCs (P<0.05 or P < 0.01), which were inhibited by m-Nis (1 x 10(-5), 1 x 10(-6), l x 10(-7), 1 x10(-8) mol · L(-1)) in dose-dependent manners (P < 0.05 or P < 0.01). Similarly, the mRNA expression of RhoA, ROCK1 and the protein expression of p-MYPT1 were also inhibited by m-Nis in different degrees (P < 0.05 or P < 0.01). Thus, the results of this study suggested that Rho/ROCK pathway played an important role in 5-HT-induced proliferation of rat PASMCs, m-Nis inhibited 5-HT-induced proliferation obviously, which may be related to the blockage of Rho/ROCK signal pathway.
ABSTRACT
Aim To explore the changes of Apelin/APJ system in LPS-induced injury of rat pulmonary mi-crovascular endothelial cells( PMVECs) , and the effect and mechanism of Apelin. Methods PMVECs were cultured with the explant technique, and the identifica-tion of rat PMVECs was carried out by immunocyto-chemical staining of factorⅧrelated antigen. MTT as-say was used to evaluate the viability of PMVECs. The mRNA expression of Apelin and APJ was detected by RT-PCR. The protein expression of PCNA and the phosphorylation of Akt was analyzed by Western blot. Results The mRNA expression of Apelin and APJ showed a compensatory increase after LPS treatment for a short period of time ( P<0. 01 ) , but with the exten-sion of time, which was significantly inhibited, even lower than the control group ( P<0. 05 or P<0. 01 ) , suggesting that Apelin/ APJ system might be involved in LPS-induced PMVECs injury. MTT results showed that 10 -6 ~10 -9 mol · L-1 Apelin obviously promoted the proliferation of rat PMVECs ( P <0. 05 or P <0. 01 ) , and with certain concentration and time de-pendence. Moreover, Apelin also improved the LPS-induced PMVECs injury in different degrees ( P<0. 05 or P < 0. 01 ) . In addition, Western blot analysis showed that Apelin significantly reversed the decrease of the protein expression of PCNA and the Akt phos-phorylation level induced by LPS ( P <0. 05 or P <0. 01 ) . Conclusions The Apelin/APJ system is in-volved in LPS-induced PMVECs injury. Apelin plays an important role in protecting the pulmonary microvas-cular endothelial function and reversing the LPS-in-duced PMVECs injury, which might be related to the activation of Akt phosphorylation pathway.
ABSTRACT
Objective To study the effects of adenosine triphosphate (ATP) on proliferation of human squamous esophageal carcinoma Eca-109 and hepatoma SMMC-7721 cells in vitro and the underlying mechanism. MethodsMTT assay was used to determine the proliferation of tumor cells. The AO/EB double stained cells were observed under fluorescence microscope. The effects of ATP on the cell cycle, apoptotic rate and apoptosis-related protein were detected by flow cytometry. Results ATP showed inhibitory effects on Eca-109 and SMMC-7721 cells at the concentration of 0.01～0.3 mmol/L. Exposure to 0.3 mmol/L ATP for 72 h, some of SMMC-7721 cells displayed morphological changes of apoptosis, but Eca-109 cells did not show the characteristics of apoptosis markedly. There was no significant change in the apoptotic rate and apoptosis-related protein of the two tumor cell lines treated with ATP 0.03, 0.1 and 0.3 mmol/L for 72 h respectively. The proportion of Eca-109 cells in G0/G1-phase of cellcycle was significantly increased, meanwhile the proportion of Eca-109 cells in S-phase and proliferation index value was significantly decreased by treatment with 0.3 mmol/L ATP. Conclusion ATP inhibited Eca-109 cell proliferation by changing the distribution of cell cycle phase, and its mechanism might not related to apoptosis, but for SMMC-7721 cell, the inhibition of cell proliferation induced by ATP was not related to the change in cell cycle.
ABSTRACT
AIM To study the role of 5-HT in antinocieption produced by intrathecal indomethacin (Ind) in mice. METHOD The antinocieption of indomethacin was investigated on the tail immersion test in mice；the contents of 5-HT, 5-HAA were assayed with fluorescent method. RESULT Dose-dependent antinocieption was observed following intrathecal administration of Ind 1.8 mg*kg-1, the effect could be obliterated when the animals were pretreated with cyproheptadine. After intrathecal administration of Ind, the content of 5-HIAA in the spinal cord of mice was significantly increased, but PG had no effect. CONCLUSION The result imply that intrathecal indomethacin could produce antinocieption; this effect is mediated by 5-HT. PG does not participate in the action of 5-HT.
ABSTRACT
AIM: To study the effects of urocortin(Ucn) on the isolated heart tissues of spontaneously hypertensive rat(SHR).METHODS: Effects of Ucn on contractile force and heart rate were observed in the SHR and Wistar rat right atrium,left atrium and right ventricle strip.RESULTS: Ucn(1-10 nmol/L) concentration-dependently increased the contractile force in the SHR and Wistar rat isolated right atrium.Ucn increased the contractile force in the SHR by(31.1?14.9)% at 3 nmol/L and by(65.7?22.4)% at 10 nmol/L,and its inotropic effect was significantly greater than that in Wistar rat(P