QALQONSIMON BEZ FAOLIYATIGA SALBIY TA’SIR KO‘RSATUVCHI KIMYOVIY BIRIKMALARNING EKSPERIMENTAL VA KLINIK TAHLILI

Аннотация

In the modern era of globalization, a scientific analysis is being conducted of the negative impact of exogenous chemicals that affect the thyroid gland, namely chemicals that disrupt endocrine function (CED), on the body, in particular on the hormonal system. Studies have shown that people of different ages and genders have different sensitivity to CED, and the effects of these substances are manifested at the stages of synthesis, transport, metabolism and binding to receptors of thyroid hormones (T3, T4, TSH). The effects of the most common industrial chemicals in scientific research - polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), perchlorates, bisphenol-A, phthalates, pesticides and perfluorinated compounds - on thyroid function are systematically studied based on clinical, experimental and epidemiological studies. They will also analyze the toxicological and molecular mechanisms leading to changes in hormonal balance and assess the level of health risk. Keywords: thyroid, hormonal disruptors, endocrine disruptors, PCBs, bisphenol-A, phthalates, pesticides, perfluorinated compounds, TSH. Kirish. Endokrin tizim organizmda gomeostazni saqlab turuvchi va turli fiziologik jarayonlarni, jumladan, o‘sish, rivojlanish, metabolizm, reproduktiv funksiyalar hamda neyropsixik faoliyatni tartibga soluvchi asosiy biologik tizimlardan biridir. So‘nggi o‘n yilliklarda endokrin tizimga salbiy ta’sir ko‘rsatadigan, tashqi muhitdan kelib chiqadigan kimyoviy moddalar - endokrin buzuvchi kimyoviy moddalarning (Endocrine Disrupting Chemicals, EDCs) salomatlikka xavf soluvchi omil sifatida ahamiyati ortib bormoqda. AQSH Atrof-muhitni muhofaza qilish agentligi (EPA) EDClarni "organizmdagi tabiiy gormonlarning sintezi, sekretsiyasi, transporti, metabolizmi, retseptorlarga bog‘lanishi yoki eliminatsiyasiga aralashuvchi har qanday tashqi kimyoviy birikma" sifatida ta’riflaydi (Diamanti-Kandarakis et al., 2009). EDClar har doim ham yuqori dozalarda emas, balki ko‘pincha past darajadagi ta’sirlanish natijasida ham sezilarli fiziologik o‘zgarishlarga olib kelishi mumkin. Bu ularning nomonotonik doza-reaksiya xususiyati bilan bog‘liq bo‘lib, bu holatda moddaning past konsentratsiyasi yuqori 1122 ResearchBib IF - 11.01, ISSN: 3030-3753, Volume 2 Issue 4 konsentratsiyasidan ko‘ra kuchliroq ta’sir ko‘rsatishi mumkin (Vandenberg et al., 2012). Ayniqsa, organizmda gormonlar nanomolyar va pikomolyar konsentratsiyada ham faoliyat ko‘rsata olish xususiyatiga ega bo‘lganligi sababli, EDClarning organizmdagi tabiiy gormonal muvozanatni buzish ehtimoli yuqori bo‘ladi. Qalqonsimon bez endokrin tizimning eng muhim organlaridan biri bo‘lib, uning ishlab chiqaradigan gormonlari (triyodtironin - T3, tetraiodyotironin - T4, va ularni boshqaruvchi tireotrop gormon - TTG) butun metabolik jarayonlarga bevosita ta’sir ko‘rsatadi. Ayniqsa, bu gormonlarning embrional va postnatal rivojlanish davrida muhim ahamiyat kasb etishi, EDClarning homiladorlik yoki bolalik davridagi ta’sirini yanada xavfli holatga keltirib qo‘yadi. So‘nggi yillarda olib borilgan tadqiqotlar shuni ko‘rsatmoqdaki, ayrim sanoat mahsulotlarida ishlatiladigan kimyoviy moddalarning - xususan, polixlorli bifenillar (PCB), polibromli difenil efirlar (PBDE), perxlorat, bisfenol-A, ftalatlar, pestitsidlar va perfluor birikmalar kabi birikmalarning - qalqonsimon bez gormonlariga salbiy ta’siri mavjud. Bu ta’sirlar gormonlar darajasining pasayishi, TTG ning kompensator ko‘tarilishi, yoki gormon retseptorlarining bloklanishi ko‘rinishida namoyon bo‘lishi mumkin. Sanoat kimyoviy moddalarining ta’siri Qalqonsimon bezning funksional muvozanatini buzuvchi sanoat kimyoviy moddalari ichida quyidagi birikmalar eng keng tarqalgan va ko‘p o‘rganilgan bo’lsada, ammo endokrin tizimga nisbatan ta’siri yetarlicha o’rganilmaganligi uchun, ilmiy tadqiqotlar orqali quyida asoslab berildi.Unga ko’ra, polixlorli bifenillar (PCB), polibromli difenil efirlar (PBDE), perxlorat, bisfenol-A, ftalatlar, pestitsidlar va perfluor birikmalar (PFAS). Quyida ushbu moddalarning organizmdagi gormonal tizimga, xususan qalqonsimon bezga ko‘rsatadigan ta’siri tadqiqotlar asosida keng yoritiladi. 2.1. PCB (Polixlorli bifenillar) Polixlorli bifenillar (PCBlar) - oldinlari elektrotexnika va pestitsid sanoatida keng qo‘llanilgan, ammo hozirda ekologik xavfli deb topilgan birikmalardir. Ular oziq-ovqat zanjiri orqali inson organizmiga kirib, gormonlar almashinuviga salbiy ta’sir ko‘rsatadi. Tadqiqotlarda aniqlanishicha, PCB moddasining ona sutidagi yuqori darajalari chaqaloqlarda TSH darajasining oshishiga, TT3 va TT4 darajalarining esa pasayishiga olib keladi (Koopmanesseboom et al., 1994; Abdelouahab et al., 2013). Ko‘rsatkich Onalarda Chaqaloqlarda TT3 ↓ - TT4 ↓ ↓ TTG - ↑ 2.2. PBDE (Polibromli difenil efirlar) PBDElar mebel, plastmassa va elektron 1123 ResearchBib IF - 11.01, ISSN: 3030-3753, Volume 2 Issue 4 qurilmalarda olovdan himoyalovchi vosita sifatida ishlatiladi. Ular T4 molekulasining tuzilishi