Effect Of TLR4-dependent P38MAPK Pathway On Adipokine Of Obstractive Sleep Apnea Syndrome With Hypertension Rats

Objective: To investigate the expression of toll-like receptor4（TLR4）-dependent p38MAPK pathway on rat adipose tissues and adipocytes ofobstractive sleep apnea syndrome（OSAS）with hypertension, and the effects toadipokine leptin; To explore the pathogenesis of OSAS with hypertension.Methods:45Sprague-Dawley (SD) male rats were randomly divided tothree groups: intermittent hypoxia4weeks (4IH), intermittent hypoxia6weeks(6IH), normal control (NC). The rats of4IH and6IH were subjected tointermittent hypoxia for8hours everyday in every90seconds per cycle ofalternative nitrogen and oxygen infusion in cabin. The oxygen concentration ofthe cabin was up to21%±0.5%and low to8%±0.5%. The rats of NC exposedin normal air without any intervention. The rats were measured tail arterial systolic pressure before the intervention and every week after the intervention.The rats of4IH and6IH were sacrificed and observed pathological changesabout myocardia and renal artery. The pathological changes of myocardium andrenal artery were observed with hematoxylin (HE) staining. The levels ofTLR4、p38MAPK mRNAand protein in adipose tissue of each group weredetected with reverse transcription polymerase chain reaction (RT-PCR) andWestern-Blot. The content changes of leptin in plasma were examined byenzyme-linked immunosorbent assay (ELISA).Rats adipocytes of each group were cultured in vitro used collagenase-digesting method. The morphological changes of the cultured cells wereobserved under microscope and the progress of proliferation was detected byflow cytometry. Preadipocytes could differentiate into adipocytes under thedifferentiation medium, and identified by oil red O. Rats adipocytes of eachgroup were divided into12groups randomly: The control group, Theintermittent hypoxia4weeks control group, The intermittent hypoxia6weeks control group, The LPS induced control group, The LPS induced4weeksgroup, The LPS induced6weeks group, The TLR4inhibited control group,8The TLR4inhibited4weeks group, The TLR4inhibited6weeks group, Thep38MAPK inhibited control group, The p38MAPK inhibited4weeks group,The p38MAPK inhibited6weeks group. The adipocytes of the control groupand treatment group were collected and detected expression of p38MAPK signal path mediated by TLR4with RT-PCR and Western-Blot. The cell culturemedium was also collected and detected content change of leptin with ELISA.Result：1Compared with normal control group, the rats of4IH and6IHshowed the significant increase of tail arterial systolic pressure and thepathological variation of OSAS by myocardial cell swelling and renal arterywall thickening. Thus pathophysiological rat models of OSAS with hypertensivewere successfully established.2Compared with normal control group，the expression of leptin inplasma of4IH and6IH were significantly up.(P<0.05, P<0.01)3Compared with normal control group, the levels of TLR4、 p38MAPKmRNA and protein in the4IH、6IH adipose tissue were increasedrapidly.(P<0.05, P<0.01)4Rats adipocytes were cultured successfully. It were observed that thecells could adherent grow within24hours and had inverted from round tospindle or polygonal spindle after3days, and get into the exponential phaseafter6days; the cultured cell were proved with higher capacity of proliferationand differentiation by flow cytometry and were induced into matureadipocytes. The mature adipocytes were observed red dye particles in cytoplasmby red O.5Compared with normal control group, the level of TLR4、p38MAPKmRNA and protein in adipocytes after LPS stimulation were significantly up.(P<0.05) and were decreased after TLR4inhibitor.(P<0.05) The level ofTLR4mRNA and protein was not detected in meaningful results afterp38MAPK inhibitor.6Compared with the negative, the expression of leptin in cell culturemedium were up after LPS stimulation and down after TLR4inhibitor. The levelof leptin was not detected in meaningful results after p38MAPK inhibitor.Conclusion: The TLR4-dependent p38MAPK pathway affects the progressof OSAS with hypertension in adipokine leptin regulation manner. This studyconfirmed the inflammatory response in fat play a role in the occurrence anddevelopment OSAS with hypertension, laid the foundation for further clinicaltreatment...