Changes and significances of thrombospondin-1 and tricarboxylic acid cycle factors under oxidative stress in polycystic ovary syndrome rats
Objective To observe the changes of thrombospondin-1(TSP-1),isocitrate dehydrogenase 1(IDH1),and ATP-citrate lyase(ACLY)under oxidative stress in rat models with letrozole induced polycystic ovary syndrome(PCOS),and to explore the improvement role of N-acetylcysteine(NAC)on oxidative stress in PCOS rats.Methods Twenty-four female SD rats were randomly divided into PCOS group(n=16)and control group(n=8).Control group received gavage with sodium carboxymethyl cellulose solution,while PCOS group received gavage with letrozole+sodium carboxymethyl cellulose solution,for 21 consecutive days.After PCOS models were established,PCOS group was randomly divided into treatment group and model group,with 8 rats each.Treatment group received gavage with NAC solution,and model group was given an equivalent volume of normal saline,for 28 consecutive days.On the next day after fasting for 28 d,the abdominal aortic blood was collected to detect the levels of testosterone(T),luteinizing hormone(LH),follicle stimulating hormone(FSH),and estradiol(E2)by ELISA,and LH/FSH was calculated.The superoxide dismutase(SOD)activity was detected by WST-1 method,and malondialdehyde(MDA)content was detected by TBA method.The bilateral ovaries were extracted to observe the appearance of the ovaries.The SOD activity was detected by WST-1 method,the MDA content was detected by TBA method,and the relative expressions of TSP-1,IDH1 and ACLY proteins were detected by Western blot.Results(1)The serum levels of T,LH,LH/FSH and MDA were higher in model group[(118.49±67.98)ng/L,(18.76±11.32)u/mL,7.85±8.66,(10.53±1.46)mmol/L]than those in control group[(28.37±8.99)ng/L,(5.02±1.92)u/mL,0.69±0.55,(3.56±1.21)mmol/L]and treatment group[(60.03±19.64)ng/L,(8.82±1.83)u/mL,1.58±0.68,(6.50± 1.02)mmol/L](P＜0.05),and the serum FSH level and SOD activity were lower in model group[(3.09±1.25),(81.50±10.20)u/mL]than those in control group[(10.56±6.55),(132.81±3.03)u/mL]and treatment group[(6.03±1.49),(147.85±3.79)u/mL](P＜0.05).(2)In model group,the ovaries were pale in color and large in size,with unevenly sized follicles palpable on the surface;the microscopy showed more immature small follicles and partially occluded follicles,with sparse granulosa cell layers.In treatment group,the ovaries were red in color and reduced in size with smooth surface;the microscopy showed a decrease in number of follicles with cystic enlargement and an increase in granulosa cell layers.(3)The MDA content in ovarian tissues was higher in model group[(20.24± 3.10)nmol/mg port]than that in control group[(4.80±1.83)nmol/mg port]and treatment group[(12.20± 1.89)nmol/mg port](P＜0.05),the SOD activity was lower in model group[(23.82±4.06)u/mg port]than that in control group[(39.35±3.03)u/mg port]and treatment group[(37.34±4.72)u/mg port](P＜0.05).(4)The relative expressions of TSP-1,ACLY and IDH1 proteins were lower in model group(0.38±0.09,0.56±0.16,0.45±0.09)than those in control group(0.97±0.15,1.32±0.32,1.03±0.19)and treatment group(0.68±0.07,1.06±0.21,0.72±0.11)(P＜0.05).Conclusions The oxidative stress indicators in serum and ovarian tissue of PCOS rats are abnormally expressed.NAC can reduce oxidative stress and improve PCOS morphology.The low level of TSP-1 under oxidative stress in PCOS rats may be correlated with the abnormal expression of tricarboxylic acid cycle factors.
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