| BackgroundChronic kidney disease(CKD) is a common disease in the nephrology department, and the prevalence rate reaches 8% to 10%. Because of its large amount of late complications and its high mortality rate, CKD is an important threat to human. About 70% CKD patients dies from cardiovascular disease and infection, which are both caused by immune reaction changes. In patients with uremia, on one hand, the immune defense ability is repressed, and the possibility of infection increases. On the other hand, the pre-activation and activation of immune cells induce inflammation and cardiovascular disease, in particular when the immune reaction could not be efficiently controlled, it would become a double-edged sword. So immune reaction plays key role in the progression of CKD.The conception of Innutrition-inflammation-atherosclerosis syndrome reveals the relationship between the CKD patients and innutrition, atherosclerosis as well as high mortality rate. The core of the conception is micro inflammation. In micro inflammation, the mononuclear phagocyte system activates and releases kinds of pro-inflammation factors, which induces inflammation injuries, and further promotes the initiation and progression of CKD.Dialysis is an alternative treatment in end-stage CKD patients, and related researches reveals that micro inflammation exists in the patients with chronic renal failure before they receive dialysis treatment. Receiving long term blood purification treatment would greatly increased the development of inflammatory reaction in CKD patients, so dialysis could not completely relieve the micro inflammation state. Many researches reveal that dialysis is with limitation, for some of the uremic toxins could bind to serum albumin which are protein-bound uremic toxins, and the current dialysis could not completely remove them. P-cresol(PC) is one of them, and in patients with impaired renal function, PC would accumulate in blood and bind to serum albumin with 94% binding rate. The low removing rate of routine dialysis allows the accumulation of PC in bodies. Researches have shown that the accumulation of PC in bodies would affect on mononuclear and phagocyte system, break their maintains of efficient immune reaction, which lead to infectious diseases or pre-activation/primer, and result to inflammation reaction. However, the effect of PC on monocyte and the mechanism are not clear.ObjectiveThe current research began with the effect and mechanism of PC on the expression of inflammation factors in monocyte, used THP-1 cell as in vitro cell model, treated cells with different concentrations of PC, detected the influence of PC on cell proliferation, the expression of monocyte related inflammation factor TNF-αand IL-10, and investigated the influence of PC on monocyte. To detect the expression of TLR-4 and explore the possible mechanism of the activation of monocyte by PC.Method(1)THP-1 cells were cultured in vitro, treated the cells with 0mg/L, 20mg/L, 40mg/L, 80mg/L, 160mg/L PC, used inverted microscope and CCK-8 to detect the proliferation rate of THP-1 cells.(2)THP-1 cells were cultured in vitro, and treated with 40mg/L, 80mg/L PC for 24 h, and then the m RNA expression of TNF-αand IL-10 in THP-1 cells were detected by RT-PCR, the protein expression were detected by Western Blot. The relationship between the changes and PC treatment was then analyzed.(3)THP-1 cells were cultured in vitro, and treated with 40mg/L, 80mg/L PC for 24 h, and then the protein expression of TLR-4 in THP-1 cells were detected by Western Blot. The relationship between the changes and PC treatment was then analyzed.Result(1)The viability of 20, 40, 80, 160mg/L P-cresol treated cell decreased to 88.18±7.81%, 87.94±5.66%, 76.03±4.55%, and 67.25±8.48% respectively after 6h, compared with control group. And the difference between 80, 160mg/L treated cell groups and control group was statistically significant(P<0.05). After 12 h and 24 h, the 80, 160mg/L treated cell groups showed similar repression on cell proliferation, compared with control group, and the cell viability decreased to 65.31±7.72%, 55.17±6.24% at 12 h and 57.65±6.14%, 52.99±9.07% at 24 h with statistical significance. The repression of PC to THP-1 cells proliferation were concentration dependent.(2)The m RNA expression of TNF-αin P-cresol treated cell increased significantly, and the 80mg/L treated group increased 1.86±0.13 folds, while the 40mg/L group was 1.2±0.06. And compared with control group, the elevation in 80mg/L treated group showed a statistical significance(P<0.05). the expression of IL-10 in THP-1 cells decreased gradually, and in 80mg/L treated group, the expression reduced to 66±13%, and the reduction was statistically significant(P<0.05). PC could promoted the release of TNF-α and repressed the expression of IL-10 at both m RNA and protein level.(3)The m RNA expression of TLR-4 in P-cresol treated cell increased significantly, and the high concentration treated group increased 2.67±0.11 folds, while the low concentration treated group was 2.08±0.1. And compared with control group, the elevation in high concentration treated group showed a statistical significance(P<0.05). And the expression of TLR-4 protein also increased, the high concentration treated group showed a stronger effect compared with the low concentration treated group, and the increase was statistically significant(P<0.05). PC could activate monocyte by TLR-4 path, mediate inflammation factor release and finally lead to micro inflammation. |
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