Platelets (thrombocytes) zvimedu zvidiki zve cytoplasm zvakaburitswa kubva ku cytoplasm yeMegakaryocyte yakakura mumwongo.Kunyangwe Megakaryocyte iriyo nhamba shoma yemasero ehematopoietic mumwongo, inongoverengera 0.05% yehuwandu hwesero yemwongo nucleated masero, maplatelet avanoburitsa akakosha zvakanyanya kune hemostatic basa remuviri.Imwe neimwe Megakaryocyte inogona kugadzira 200-700 maplatelet.
Nhamba yeplatelet yemunhu mukuru ndeye (150-350) × 109/L.Platelets ane basa rekuchengetedza kuvimbika kwemadziro emidziyo yeropa.Apo nhamba yeplatelet inoderera kusvika ku50 × Kana BP iri pasi pe109/L, kukuvadzwa kuduku kana kungowedzera kuwedzera kweropa kunogona kukonzera ropa stasis mavara paganda uye submucosa, uye kunyange purpura yakakura.Izvi zvinodaro nekuti maplatelet anogona kugara pamadziro evascular panguva ipi neipi kuti azadze mapeji akasiiwa ne endothelial cell detachment, uye anogona kusanganisa muvascular endothelial masero, ayo anogona kuita basa rakakosha mukuchengetedza endothelial cell kutendeseka kana kugadzirisa endothelial masero.Kana paine maplatelet mashoma, mabasa aya anonetsa kupedzisa uye pane tsika yekubuda ropa.Maplatelet ari muropa rinotenderera anowanzo ari mu "stationary" mamiriro.Asi kana tsinga dzeropa dzakuvadzwa, maplatelet anoitwa kuburikidza nekusangana kwepamusoro uye kuita kwezvimwe zvinhu coagulation.Akabatidzwa maplatelet anogona kuburitsa zvakatevedzana zvezvinhu zvinodikanwa kune hemostatic process uye kurovedza muviri mabasa akadai sekunamatira, kuunganidza, kuburitsa, uye adsorption.
Platelet inogadzira Megakaryocyte inotorwawo kubva kuhematopoietic stem masero mumwongo.Hematopoietic stem masero anotanga kusiyanisa kuita megakaryocyte progenitor masero, anozivikanwawo sekoloni inoumba unit megakaryocyte (CFU Meg).Machromosomes ari munucleus ye progenitor cell stage anowanzoita 2-3 ploidy.Apo masero ekutanga ari diploid kana tetraploid, masero ane simba rekuwedzera, saka iyi ndiyo nhanho apo mitsara yeMegakaryocyte inowedzera nhamba yemasero.Apo megakaryocyte progenitor masero akawedzera kusiyanisa kuva 8-32 ploidy Megakaryocyte, cytoplasm yakatanga kusiyanisa uye Endomembrane system zvishoma nezvishoma yakapera.Pakupedzisira, membrane chinhu chinoparadzanisa cytoplasm yeMegakaryocyte munzvimbo dzakawanda diki.Kana sero rimwe nerimwe raparadzaniswa zvachose, rinova platelet.Rimwe nerimwe, maplatelet anodonha kubva kuMegakaryocyte kuburikidza nemukaha uri pakati peendothelial masero emadziro e sinus yevheini uye kupinda muropa.
Kuva akasiyana zvachose immunological properties.TPO inonzi glycoprotein inonyanya kugadzirwa neitsvo, ine molecular uremu hunosvika 80000-90000.Apo maplatelet ari muropa anoderera, kuwedzera kweTPO muropa kunowedzera.Mabasa eichi chinongedzo anosanganisira: ① kuwedzera DNA synthesis mumasero ekutanga uye kuwedzera huwandu hwema polyploids;② Kurudzira Megakaryocyte kugadzira mapuroteni;③ Wedzera huwandu hwese hweMegakaryocyte, zvichikonzera kuwedzera kwekugadzirwa kweplatelet.Parizvino, zvinotendwa kuti kupararira uye kusiyanisa kweMegakaryocyte kunonyanya kutungamirirwa nezvinhu zviviri zvinogadzirisa pamatanho maviri ekusiyanisa.Aya maviri anodzora megakaryocyte Colony-stimulating factor (Meg CSF) uye Thrombopoietin (TPO).Meg CSF chinhu chinodzora icho chinonyanya kuita pane progenitor cell nhanho, uye basa rayo ndere kudzora kuwanda kwe megakaryocyte progenitor masero.Kana huwandu hweMegakaryocyte mumapfupa emapfupa hunoderera, kugadzirwa kwechinhu ichi chekutonga kunowedzera.
Mushure mokunge maplatelet apinda muropa, anongova nemabasa ehupenyu kwemazuva maviri ekutanga, asi mararamiro avo akaenzana anogona kuva mazuva 7-14.Muzviitiko zve physiological hemostatic, maplatelet pachawo achaparara uye anoburitsa zvese zvinoshanda zvinhu mushure mekuunganidzwa;Inogonawo kubatanidzwa muvascular endothelial masero.Pamusoro pekuchembera uye kuparadzwa, maplatelet anogona zvakare kudyiwa panguva yekushanda kwavo kwemuviri.Kuchembera maplatelet akaputirwa nespleen, chiropa, uye mapapu tishu.
1. Ultrastructure yemaplatelet
Mumamiriro ezvinhu akajairwa, maplatelet anoonekwa sediki convex discs kumativi ese, ane avhareji dhayamita ye2-3 μ m.Avhareji yevhoriyamu ndeye 8 μ M3.Platelets ndiwo masero ane nucleated asina chimiro chakananga pasi pe microscope, asi yakaoma ultrastructure inogona kuonekwa pasi pe electron microscope.Parizvino, chimiro cheplatelet chinowanzo kupatsanurwa munzvimbo yakatenderedza, sol gel nzvimbo, Organelle nzvimbo uye yakakosha membrane system nzvimbo.
Iyo yakajairika platelet pamusoro yakatsetseka, ine zvimiro zvidiki zveconcave zvinoonekwa, uye yakavhurika canalicular system (OCS).Nzvimbo yakatenderedza yeplatelet surface inoumbwa nezvikamu zvitatu: iyo yekunze layer, unit membrane, uye submembrane nzvimbo.Ijasi rinonyanya kuumbwa nemhando dzakasiyana-siyana dzeglycoproteins (GP), dzakadai seGP Ia, GP Ib, GP IIa, GP IIb, GP IIIa, GP IV, GP V, GP IX, etc. Inoumba zvakasiyana-siyana zvekunamatira uye inogona kubatana. kuTSP, thrombin, collagen, fibrinogen, nezvimwewo. Zvakakosha kuti maplatelet atore chikamu mukugwinya uye kudzivirira immune.Iyo unit membrane, inozivikanwawo se plasma membrane, ine mapuroteni zvidimbu zvakaiswa mu lipid bilayer.Nhamba uye kugoverwa kwezvikamu izvi zvine hukama neplatelet adhesion uye coagulation basa.Iyo membrane ine Na+- K+ - ATPase, iyo inochengetedza iyo ion yekumisikidza musiyano mukati uye kunze kwe membrane.Iyo submembrane zone iri pakati pechikamu chezasi cheyuniti membrane uye nekunze kweiyo microtubule.Submembrane nzvimbo ine submembrane filaments uye Actin, ayo ane hukama neplatelet adhesion uye aggregation.
Microtubules, microfilaments uye submembrane filaments zvakare iripo munzvimbo ye sol gel yemaplatelet.Izvi zvinhu zvinoumba skeleton uye contraction system yemaplatelet, ichiita basa rakakosha mukushanduka kweplatelet, kuburitswa kwechikamu, kutambanudza, uye kuvharika kwegwamba.Microtubules inoumbwa neTubulin, inoverengera 3% yehuwandu hweplatelet protein.Basa ravo guru nderokuchengetedza chimiro cheplatelet.Microfilaments inonyanya kuve neActin, inova puroteni yakawanda kwazvo mumaplatelet uye inoverengera 15% ~ 20% yehuwandu hwemaplatelet protein.Submembrane filaments inonyanya kuita fiber components, izvo zvinogona kubatsira Actin-binding protein uye Actin crosslink kuita mabundle pamwechete.Pamusoro pekuvapo kweCa2 +, actin inobata pamwe neprothrombin, contractin, kusunga mapuroteni, co actin, myosin, nezvimwewo kupedzisa kushanduka kweplatelet shape, pseudopodium formation, cell contraction nezvimwe zviito.
Tafura 1 Main Platelet Membrane Glycoproteins
Nzvimbo yeOrganelle inzvimbo iyo kune marudzi mazhinji eOrganelle mumaplatelet, ane simba rakakosha pakushanda kwemaplatelet.Iyo zvakare inzvimbo yekutsvagisa mukurapa kwemazuva ano.Izvo zvakakosha zvakanyanya munzvimbo yeOrganelle zvimedu zvakasiyana, senge α Particles, dense particles (δ Particles) uye Lysosome ( λ Particles, nezvimwewo, ona Tafura 1 yeruzivo.α Granules inzvimbo dzekuchengetera mumaplatelet anogona kuburitsa mapuroteni.Pane zvinopfuura gumi muplatelet yega yega α Particles.Tafura 1 inonyora chete zvikamu zvikuru, uye maererano nekutsvaga kwemunyori, zvakaonekwa kuti α Kune anopfuura 230 mazinga eplatelet derived factor (PDF) iripo mumagranules.Dense particle ratio α Zvimedu zvidiki zvishoma, zvine dhayamita ye250-300nm, uye kune 4-8 dense zvidimbu muplatelet yega yega.Parizvino, zvakaonekwa kuti 65% yeADP neATP inochengetwa muzvikamu zvakasvibirira mumaplatelet, uye 90% ye5-HT muropa inochengetwawo muzvikamu zvakadzika.Naizvozvo, dense zvimedu zvakakosha pakuunganidzwa kweplatelet.Iko kugona kuburitsa ADP uye 5-HT iri kushandiswawo mukiriniki kuongorora platelet secretion basa.Pamusoro pezvo, dunhu rino zvakare rine mitochondria neLysosome, iri zvakare hotspot yekutsvagisa kumba nekune dzimwe nyika gore rino.The 2013 Nobel Prize in Physiology and Medicine yakapiwa kune vatatu vesainzi, James E. Rothman, Randy W. Schekman, naThomas C. S ü dhof, nekutsvaga zvakavanzika zvemukati mekutakura nzira.Kune zvakare akawanda asingazivikanwe minda mumetabolism yezvinhu uye simba mumaplatelet kuburikidza nemukati memuviri miviri uye Lysosome.
Iyo yakakosha membrane system nharaunda inosanganisira OCS uye dense tubular system (DTS).OCS igadziriro yepombi ine tortuous inoumbwa nepamusoro pemaplatelet anonyura mukati memaplatelet, ichiwedzera zvakanyanya nzvimbo yeplatelet inosangana neplasma.Panguva imwecheteyo, ndeye extracellular chiteshi chekuti zvinhu zvakasiyana zvipinde mumaplatelet uye kuburitsa zvakasiyana-siyana zvemukati zvemaplatelet.Iyo pombi yeDTS haina kubatana kune yekunze uye inzvimbo yekubatanidza zvinhu mukati memasero eropa.
2. Iyo Physiological Basa rePlatelets
Basa guru rehutano hwemaplatelet nderekutora chikamu muhemostasis uye thrombosis.Izvo zvinoshanda zvemaplatelet panguva ye physiological hemostasis inogona kukamurwa kuita zvikamu zviviri: yekutanga hemostasis uye yechipiri hemostasis.Maplatelet anoita basa rakakosha mumatanho ese ehemostasis, asi maitiro chaiwo aanoshanda nawo achiri akasiyana.
1) Iyo yekutanga hemostatic basa remaplatelet
Iyo thrombus inoumbwa panguva yekutanga hemostasis inonyanya kuchena thrombus, uye activation maitiro akadai seplatelet adhesion, deformation, kuburitsa, uye kuunganidza inzira dzakakosha mukutanga hemostasis process.
I. Platelet adhesion reaction
Iko kunamatira pakati pemaplatelet neasiri maplatelet nzvimbo inonzi platelet adhesion, inova nhanho yekutanga kutora chikamu mune yakajairika hemostatic reactions mushure mekukuvadzwa kwevascular uye danho rakakosha mu pathological thrombosis.Mushure mekukuvadzwa kwevascular, maplatelet anoyerera nemudziyo uyu anoshandiswa nepamusoro peganda pasi pevascular endothelium uye pakarepo anonamatira kune akafumurwa collagen fibers panzvimbo yekukuvara.Pamaminetsi gumi, maplatelet akaiswa munharaunda akasvika pakukosha kwawo, achigadzira magwamba eropa machena.
Zvinhu zvikuru zvinosanganisirwa mukuita kweplatelet adhesion zvinosanganisira platelet membrane glycoprotein Ⅰ (GP Ⅰ), von Willebrand factor (vW factor) uye collagen mune subendothelial tishu.Mhando huru dze collagen dziripo pamadziro evascular ndiyo mhando I, III, IV, V, VI, uye VII, pakati pemhando I, III, uye IV collagen ndiyo inonyanya kukosha kune platelet adhesion process pasi pemamiriro ekuyerera.Iyo vW factor ibhiriji rinobatanidza kusungirirwa kweplatelet kuti iite I, III, uye IV collagen, uye glycoprotein chaiyo receptor GP Ib pane platelet membrane ndiyo nzvimbo huru yeplatelet collagen inosunga.Mukuwedzera, glycoproteins GP IIb / IIIa, GP Ia / IIa, GP IV, CD36, uye CD31 pane platelet membrane inobatanidzwawo mukunamatira kune collagen.
II.Platelet aggregation reaction
Chiitiko chemaplatelet anonamatira kune mumwe nemumwe anonzi aggregation.The aggregation reaction inoitika neadhesion reaction.Pamberi peCa2+, platelet membrane glycoprotein GPIIb/IIIa uye fibrinogen aggregate yakaparadzira maplatelet pamwe chete.Platelet aggregation inogona kukonzereswa nemaitiro maviri akasiyana, imwe yakasiyana makemikari inducers, uye imwe inokonzerwa nekuveura kushushikana pasi pemamiriro ekuyerera.Panotanga kuunganidzwa, maplatelet anochinja kubva pachimiro chedisiki kuenda kuchimiro chedenderedzwa uye anobuda dzimwe tsoka dzemanyepo dzinoita seminzwa midiki;Panguva imwecheteyo, platelet degranulation inoreva kuburitswa kwezvinhu zvinoshanda senge ADP uye 5-HT izvo zvakambochengetwa mune dense particles.Kuburitswa kweADP, 5-HT uye kugadzirwa kweimwe Prostaglandin kwakakosha pakuunganidza.
ADP ndiyo inonyanya kukosha kuunganidzwa kweplatelet, kunyanya endogenous ADP yakaburitswa mumaplatelet.Wedzera zvishoma zvishoma ADP (concentration pa 0.9) kune platelet suspension μ Pazasi mol / L), inogona kukurumidza kukonzera platelet aggregation, asi nekukurumidza depolymerize;Kana zviyero zvine mwero zveADP (1.0) zvichiwedzerwa μ Pakutenderedza mol/L, chikamu chechipiri chisingachinjiki chekuunganidza chinoitika nguva pfupi mushure mekupera kwechikamu chekutanga chekubatanidza uye chikamu che depolymerization, icho chinokonzerwa neiyo endogenous ADP yakaburitswa nemaplatelet;Kana huwandu hukuru hweADP huchiwedzerwa, hunokurumidza kukonzeresa kusagadziriswa, iyo inopinda zvakananga muchikamu chechipiri chekuunganidza.Kuwedzera maitiro akasiyana-siyana e-thrombin kune platelet kumiswa kunogonawo kukonzera platelet aggregation;Uye zvakafanana neADP, sezvo muyero unowedzera zvishoma nezvishoma, kudzokororwa kwekugadzirisa kunogona kuonekwa kubva pachikamu chekutanga chete kusvika pakuonekwa kwezvikamu zviviri zvekuunganidza, uye zvino zvakananga kupinda muchikamu chechipiri chekuunganidza.Nekuda kwekuti kuvhara kuburitswa kwe endogenous ADP neadenosine kunogona kuvharidzira kuunganidzwa kweplatelet kunokonzerwa nethrombin, inoratidza kuti mhedzisiro yethrombin inogona kukonzerwa nekusungwa kwethrombin kune thrombin receptors pane platelet cell membrane, zvichitungamira mukuburitswa kwe endogenous ADP.Kuwedzerwa kwe collagen kunogonawo kukonzera kuunganidzwa kweplatelet mukumiswa, asi kungounganidzwa kusingachinjike muchikamu chechipiri kunowanzo tenda kunokonzerwa nekuburitswa kweADP kunokonzerwa necollagen.Zvinhu zvinogona kukonzera kuunganidzwa kweplatelet zvinogona kuderedza cAMP mumaplatelet, nepo izvo zvinodzivirira kuunganidzwa kweplatelet zvinowedzera cAMP.Nokudaro, pari zvino inofungidzirwa kuti kuderera kwekampu kunogona kukonzera kuwedzera kweCa2 + mumaplatelet, kukurudzira kusunungurwa kweADP endogenous.ADP inokonzeresa kuunganidzwa kweplatelet, izvo zvinoda kuvepo kweCa2 + uye fibrinogen, pamwe nekushandiswa kwesimba.
Basa replatelet Prostaglandin Phospholipid yeplatelet plasma membrane ine Arachidonic acid, uye sero replatelet rine Phosphatidic acid A2.Kana maplatelet akaitwa pamusoro, Phospholipase A2 inoshandiswawo.Pasi pe catalysis yePhospholipase A2, Arachidonic acid inoparadzaniswa kubva kune phospholipids mu membrane yeplasma.Arachidonic acid inogona kuumba yakawanda yeTXA2 pasi pe catalysis ye platelet cyclooxygenase uye Thromboxane synthase.TXA2 inoderedza cAMP mumaplatelet, zvichiita kuti platelet aggregation yakasimba uye vasoconstriction effect.TXA2 hainawo kugadzikana, saka inokurumidza kushandura kuita isingaite TXB2.Mukuwedzera, masero e-vascular endothelial akajairika ane prostacyclin synthase, iyo inogona kukonzera kugadzirwa kweprostacyclin (PGI2) kubva kumaplatelet.PGI2 inogona kuwedzera cAMP mumaplatelet, saka ine yakasimba inhibitory mhedzisiro pane platelet aggregation uye Vasoconstriction.
Adrenaline inogona kupfuudzwa kuburikidza ne α 2. Kupindirana kweAdrenergic receptor kunogona kukonzera biphasic platelet aggregation, pamwe nehuwandu hwe (0.1 ~ 10) μ Mol / L.Thrombin pazvikamu zvakaderera (<0.1 μ At mol / L, chikamu chekutanga kusanganiswa kweplatelet kunonyanya kukonzerwa nePAR1; Pakukwirira kwakanyanya (0.1-0.3) μ Pa mol / L, chikamu chechipiri chekubatanidza chinogona kukonzerwa nePAR1 uye PAR4. Mishonga yakasimba yeplatelet aggregation inosanganisirawo platelet activating factor (PAF), collagen, vW factor, 5-HT, zvichingodaro. atherosclerosis.
III.Platelet release reaction
Kana maplatelet akaiswa pasi pekukurudzira kwemuviri, anochengetwa muzvikamu zvakakora α Chiitiko chezvinhu zvakawanda muzvidimbu uye lysosomes ari kudzingwa kubva mumasero anonzi kusunungurwa reaction.Basa remaplatelet mazhinji rinowanikwa kuburikidza neiyo biological mhedzisiro yezvinhu zvinoumbwa kana kuburitswa panguva yekuburitsa maitiro.Anenge ese inducers anokonzera platelet aggregation anogona kukonzera kuburitsa reaction.Mhedzisiro yekuburitsa inowanzoitika mushure mechikamu chekutanga kuunganidzwa kwemaplatelet, uye chinhu chinoburitswa nekuburitswa chinokonzeresa chikamu chechipiri kuunganidzwa.Iwo ma inducers anokonzera kuburitsa maitiro anogona kukamurwa kuita:
i.Inducer isina simba: ADP, adrenaline, Norepinephrine, vasopressin, 5-HT.
ii.Epakati inducers: TXA2, PAF.
iii.Inducers yakasimba: thrombin, pancreatic enzyme, collagen.
2) Basa remaplatelet muropa coagulation
Maplatelet anonyanya kutora chikamu mune zvakasiyana-siyana coagulation reactions kuburikidza ne phospholipids uye membrane glycoproteins, kusanganisira adsorption uye activation ye coagulation zvinhu (zvinhu IX, XI, uye XII), kuumbwa kwe coagulation inosimudzira makomba pamusoro pe phospholipid membranes, uye kukurudzira kweprothrombin kuumbwa.
Iyo plasma membrane iri pamusoro peplatelet inosunga kune zvakasiyana-siyana coagulation zvinhu, senge fibrinogen, factor V, factor XI, factor XIII, etc. uye PF3 zvose zviri kusimudzira kubatanidza ropa.PF4 inogona kuderedza heparin, nepo PF6 inhibits fibrinolysis.Kana maplatelet akabatidzwa pamusoro, anogona kukurumidza kumhanyisa maitiro ekuita kweiyo coagulation zvinhu XII uye XI.Iyo phospholipid surface (PF3) inopiwa nemaplatelet inofungidzirwa kukurumidza kushandiswa kweprothrombin ne20000 nguva.Mushure mekubatanidza zvinhu Xa uye V pamusoro peiyi phospholipid, vanogona zvakare kuchengetedzwa kubva kune inhibitory mhedzisiro ye antithrombin III uye heparin.
Kana maplatelet akaungana kuti aite hemostatic thrombus, iyo coagulation process yakatoitika munharaunda, uye maplatelet akafumura huwandu hukuru hwe phospholipid nzvimbo, zvichipa mamiriro akanyanya kunaka e activation ye factor X uye prothrombin.Kana maplatelet achikurudzirwa ne collagen, thrombin kana kaolin, Sphingomyelin nePhosphatidylcholine iri kunze kweplatelet membrane inoshanduka ne phosphatidyl Ethanolamine uye phosphatidylserine mukati, zvichiita kuti kuwedzera kwephosphatidyl Ethanolamine nerine phosphatidyl pamusoro pepamusoro pemembrane.Iwo ari pamusoro apa phosphatidyl mapoka akatenderedza pamusoro pemaplatelet anotora chikamu mukuumbwa kwemavhesi pane membrane pamusoro panguva yekushandiswa kweplatelet.Iwo ma vesicles anobvisa uye anopinda mukutenderera kweropa kugadzira microcapsules.Iwo ma vesicles uye microcapsules akapfuma mu phosphatidylserine, iyo inobatsira mukuungana uye activation yeprothrombin uye inotora chikamu mukusimudzira kweropa coagulation.
Mushure mokunge platelet aggregation, ayo α Kusunungurwa kwezvinhu zvakasiyana-siyana zveplatelet muzvikamu zvinokurudzira kuumbwa uye kuwedzera kweropa re fiber, uye kunoteya mamwe masero eropa kuti aumbe mavha.Nokudaro, kunyange zvazvo maplatelet achiparara zvishoma nezvishoma, hemostatic emboli inogona kuramba ichiwedzera.Maplatelet akasiiwa mugwamba reropa ane pseudopodia anopinda muropa re fiber network.Maproteins echibvumirano ari mumaplatelet aya anobatana, zvichiita kuti kugwamba kweropa kudzoke, kusvina serum uye kuita plug yakasimba yehemostatic, ichivhara zvakasimba mukaha wevascular.
Kana uchimisikidza maplatelet uye iyo coagulation system pamusoro, zvakare inomutsa iyo fibrinolytic system.Iyo Plasmin uye activator yayo iri mumaplatelet ichaburitswa.Kusunungurwa kwe serotonin kubva muropa fiber uye maplatelet kunogonawo kukonzera endothelial masero kusunungura activators.Zvisinei, nekuda kwekuparara kweplatelet uye kusunungurwa kwePF6 nezvimwe zvinhu zvinodzivisa proteases, hazvibatsirwi nebasa re fibrinolytic panguva yekugadzirwa kweropa.
(Zviri muchinyorwa ichi zvakadhindwa patsva, uye isu hatipe chero vimbiso yechokwadi, kuvimbika kana kuzara kwezviri muchinyorwa chino, uye hatina mhosva yemafungiro echinyorwa ichi, ndapota nzwisisa.)
Nguva yekutumira: Jun-13-2023