METHODS: MTT assay was used to determine the half-maximal inhibitory concentration (IC50), while the combination index (CI) value was utilized to analyze the interaction within each combination. The antiproliferative effect of the treatment was evaluated by trypan blue exclusion assay. The morphological changes of cells were observed under a phase-contrast inverted microscope. The nuclear morphology and percentage of apoptosis cells were evaluated by using the Hoechst 33258 staining and annexin V/PI assay, respectively.
RESULTS: The U2OS cells showed cytotoxic effect when treated with TA and cisplatin, with IC50 at 4.47 µg/mL and 16.25 µg/mL, respectively. The TA demonstrated no significant inhibition effect on the normal human fetal osteoblast cells (hFOB 1.19); yet, interestingly, a potent proliferative effect was indicated. Synergistic interaction was triggered when TA was combined with cisplatin at percentage ratios of 90:10 and 85:15. Meanwhile, antagonistic interaction was induced in the combination at percentage ratios of 75:25 and 50:50. On the other hand, a significant antiproliferative effect with prominent morphological alteration was detected in the cells treated with a combination of TA and cisplatin at the percentage ratio of 90:10. Additionally, combination-treated cells demonstrated the highest percentage of apoptosis cells, with distinct chromosomal condensation, nuclear fragmentation, reduction of nuclear volume, and notable apoptotic body.
CONCLUSION: Therefore, there is a high potential for the inclusion of TA in the cisplatin-based chemotherapeutic regimen of osteosarcoma.
METHODS: Male Sprague Dawley rats were subjected to normal condition, REM sleep deprivation and control wide platform condition for 72 hr. During this procedure, saline or nicotine (1 mg/kg) was given subcutaneously twice a day. Then, Morris water maze (MWM) test was used to assess learning and memory performance of the rats. The rats were sacrificed and the brain was harvested for immunohistochemistry and Western blot analysis.
RESULTS: MWM test found that REM sleep deprivation significantly impaired learning and memory performance without defect in locomotor function associated with a significant increase in hippocampus DREAM protein expression in CA1, CA2, CA3, and DG regions and the mean relative level of DREAM protein compared to other experimental groups. Treatment with acute nicotine significantly prevented these effects and decreased expression of DREAM protein in all the hippocampus regions but only slightly reduce the mean relative level of DREAM protein.
CONCLUSION: This study suggests that changes in DREAM protein expression in CA1, CA2, CA3, and DG regions of rat's hippocampus and mean relative level of DREAM protein may involve in the mechanism of nicotine treatment-prevented REM sleep deprivation-induced learning and memory impairment in rats.