肝癌细胞外泌体的分离与鉴定

目的:针对目前尚缺理想的肿瘤细胞提取方案,探寻分离纯化肝癌细胞培养液中外泌体的新方法.方法:连续适应无血清培养肝癌SMMC-7721细胞,收集细胞上清液,采用改良超速离心法分离、纯化培养上清液中肝癌细胞外泌体;透射电镜观察其形态,Nanosight技术分析粒径;Western blot分析其特异蛋白Alix、CD63、CD9的表达并利用SDS-PAGE电泳分析肝癌细胞和外泌体的蛋白谱.结果:透射电镜观察到的肝癌细胞外泌体,外形呈圆形或椭圆形;Nanosight技术分析颗粒直径峰值为122 nm,直径30-150 nm之间颗粒占72.16%;Western blot证实在细胞培养上清液和外泌体提取液中均能检测到Alix、CD63、CD9的蛋白表达;SDS-PAGE电泳清晰显示外泌体中高丰度大分子结构蛋白明显少于肝癌细胞.结论:利用连续适应无血清细胞培养结合改良超速离心法能提取高纯度的外泌体,为肝癌细胞外泌体标志物研究奠定基础.     

特发性膜性肾病尿液外泌体表达及临床意义

目的探讨特发性膜性肾病(IMN)患者尿液外泌体的表达及临床意义。方法对2016年9月至2018年1月盛京医院肾病科住院的49例IMN患者(IMN组)及同期21例健康志愿者(对照组)通过差速离心方法提取尿液外泌体,通过Westernblot检测外泌体标记蛋白(Alix,CD63和TSG101)的表达,将其与24h尿蛋白定量,估计肾小球滤过率和肾组织病变等临床病理指标做统计分析。结果 IMN患者尿液外泌体较对照组显著增加[Alix(t=12.74,P 0.0001),CD63(t=13.98,P 0.0001),TSG101(t=15.68,P0.0001)],外泌体标记蛋白与蛋白尿呈正相关[Alix(r=0.451,P=0.002),CD6(r=0.408,P=0.002),TSG101(r=0.417,P0.001)];尿液外泌体蛋白浓度与蛋白尿呈正相关(r=0.635,P0.001)。肾组织补体C3和PLA2R荧光染色增强组较染色较弱组尿液外泌体表达均显著增加[分别为Alix(t=3.071,P=0.004; t=2.07,P=0.046),CD63(t=2.69,P=0.01; t=3.43,P=0.002),TSG101(t=3.493,P=0.001; t=2.202,P=0.036)];尿外泌体标记蛋白(Alix,CD63和TSG101)诊断IMN的ROC曲线下面积分别是0.922[95%CI(0.843～1.002),P0.001],0.936[95%CI(0.868～1.003),P0.001]和0.944[95%CI(0.893～0.996),P0.001]。随访研究表明尿外泌体在保守治疗无效组以及免疫制剂有效或无效组中表达均增加。结论尿液外泌体可反映IMN活动性肾组织病理改变,有希望成为IMN疾病诊断、病情评估和预后判断的非侵入性生物标志物。     

胰高糖素样肽-1受体激活对肝星状细胞p38MAPK信号通路的影响

目的 探讨肝星状细胞(HSC)上胰高糖素样肽-1(GLP-1)受体激活对胞内p38MAPK信号通路的影响. 方法 体外培养人HSC并进行形态学鉴定,随机选取样本用Western blot法检测其GLP-1受体蛋白的表达情况;设立对照组和实验组HSC进行体外培养,实验组予以GLP-1受体激动剂-利拉鲁肽,对照组予以等量等渗盐水,细胞培养120 h后用RT-PCR检测各样本的p38MAPK mRNA表达水平,用Western blot检测各样本磷酸化p38MAPK蛋白表达水平.对数据进行两独立样本均数t检验分析. 结果 人HSC上存在GLP-1受体蛋白的表达.实验组和对照组相比,磷酸化p38MAPK蛋白相对表达水平下降,差异具有统计学意义(18.0±2.8与21.2±2.5,t=3.814,P＜0.01);p38MAPK mRNA相对表达水平亦下降,差异亦具有统计学意义(37.9±2.4与43.3±4.7,t=4.478,P＜0.01). 结论 HSC上GLP-1受体激活后能够下调HSC内p38MAPK mRNA的表达,也能够降低胞内磷酸化的p38MAPK蛋白水平,起到抑制p38MAPK信号通路的作用.     

CD137信号通过外泌体传递活化T细胞核因子c1介导小鼠血管平滑肌细胞钙化

目的探讨外泌体在CD137信号诱导的小鼠血管平滑肌细胞(VSMC)钙化中的作用。方法组织贴壁法提取小鼠胸主动脉VSMC,将细胞分为2组,即对照组和CD137激动组,用试剂盒提取外泌体,并用透射电镜、纳米颗粒跟踪分析法及Western blot鉴定和分析,荧光显微镜观察VSMC摄取外泌体。构建活化T细胞核因子c1(sh-NFATc1)慢病毒载体并感染VSMC。实验分为3组:对照组外泌体处理组、CD137激动组外泌体处理组、沉默NFATc1+CD137激动组外泌体处理组。采用Western blot检测α平滑肌肌动蛋白(α-SMA)、骨形成蛋白2(BMP-2)、Runt相关转录因子2(Runx-2)蛋白表达量。Von Kossa染色检测VSMC内钙盐沉积情况。结果 Western blot结果显示,2组微囊泡均表达外泌体表面标记蛋白CD9、CD81;电镜下外泌体成圆形和杯托状,直径在30～100 nm;CD137激动组外泌体中NFATc1蛋白表达显著增多。与对照组外泌体处理组比较,CD137激动组外泌体处理组钙化相关指标BMP-2、Runx-2蛋白表达显著增高,同时α-SMA表达显著下降;与CD137激动组外泌体处理组比较,沉默NFATc1+CD137激动组外泌体处理组BMP-2、Runx-2蛋白表达显著减少,α-SMA表达显著增高。Von Kossa染色结果显示,CD137激动组外泌体处理组VSMC钙盐沉积多于对照组外泌体处理组,而沉默NFATc1+CD137激动组外泌体处理组钙盐沉积比CD137激动组外泌体处理组显著降低。结论 CD137信号通路通过外泌体转运NFATc1介导VSMC钙化。     

宫颈癌细胞分泌外泌体对宫颈癌细胞增殖、凋亡功能及MAPK/ERK信号通路的影响

目的探讨宫颈癌细胞分泌外泌体对宫颈癌细胞增殖、凋亡功能及丝裂原活化蛋白激酶/胞外信号调节激酶(MAPK/ERK)信号通路的影响。方法采用超速离心法分离宫颈癌C33A细胞外泌体。将C33A细胞分为外泌体(Exo)组和对照(C)组,Exo组C33A细胞用含外泌体的培养基培养,C组C33A细胞用不含外泌体的培养基培养。MTT测定C33A细胞增殖能力,克隆形成实验测定C33A细胞集落形成能力,流式细胞术测定C33A细胞凋亡能力,Western印迹测定C33A细胞中ERK1/2、磷酸化(p)ERK1/2蛋白水平。结果1 d、3 d、5 d,Exo组C33A细胞A值明显高于C组(P<0.05),Exo组C33A细胞集落形成数明显高于C组(P<0.05),Exo组C33A细胞凋亡率明显低于C组(P<0.05),两组C33A细胞ERK1/2蛋白水平差异无统计学意义(P>0.05);Exo组C33A细胞p-ERK1/2蛋白水平明显高于C组(P<0.05)。结论宫颈癌C33A细胞来源外泌体可促进C33A细胞增殖、抑制其凋亡,其机制可能与C33A细胞外泌体可激活MAPK/ERK信号通路有关。     

沙眼衣原体pORF5质粒蛋白激活p38MAPK和NALP3信号通路调控THP-1细胞IL-1β分泌的研究

目的研究沙眼衣原体(Chlamydia trachomatis,Ct)pORF5质粒蛋白诱导THP-1细胞产生IL-1β的分子机制,为阐明Ct致病机制提供实验依据。方法将原核表达重组体pGEX-6p/pORF5转化大肠埃希菌,表达并纯化GST-pORF5融合蛋白,融合蛋白经蛋白酶酶切后制备不含GST标签的pORF5蛋白;用不同浓度的pORF5蛋白体外刺激THP-1细胞,ELISA测定不同时间IL-1β水平;分别用NALP3siRNA、ASC siRNA、Caspase-1抑制剂和p38抑制剂预处理THP-1细胞,再用pORF5蛋白刺激THP-1细胞24h,ELISA测定IL-1β含量,Real-time PCR测定IL-1β和NALP3炎性体mRNA的表达,Western blot分析Caspase-1的表达及p38磷酸化水平。结果 pORF5蛋白以剂量和时间依赖的方式刺激THP-1细胞产生IL-1β,24μg/ml pORF5蛋白刺激24h时IL-1β的表达水平达到峰值(495.1±55.5pg/ml);pORF5蛋白能促进THP-1细胞中NALP3炎性体mRNA的表达;NALP3-siRNA、ASC-siRNA及Caspase-1抑制剂预处理THP-1细胞后,IL-1β分泌量分别降低37.7%、71.3%和40.1%;p38抑制剂能降低NALP3炎性体mRNA及IL-1β分泌量(P0.01),但抑制NALP3炎性体后p38磷酸化水平未受影响(P0.05)。结论 pORF5质粒蛋白通过激活p38MAPK和NALP3信号通路共同调控IL-1β的产生和分泌。     

细胞毒性T淋巴细胞来源外泌体抑制肝星状细胞活化的机制

目的 探讨细胞毒性T淋巴细胞（CTL）来源外泌体能否下调HBx表达从而抑制肝星状细胞（HSC）活化。方法 收集HepG2、HepGA14、CTL细胞上清液提取外泌体（分别简写为NC-exo、HBV-exo、CTL-exo），透射电镜观察其形态，Western Blot检测外泌体标志物CD63和TSG101的表达。将氟硼二吡咯染料（BODIPY）标记的NC-exo、HBV-exo以及CTL-exo与HBV-exo按不同比例混合后，分别与HSC LX-2(HSC-LX2)共培养，荧光显微镜观察外泌体能否进入LX-2细胞，倒置显微镜观察细胞形态学改变，实时荧光定量PCR (qPCR)检测LX-2细胞中TGF-β1、α-平滑肌肌动蛋白（α-SMA）、Ⅰ型胶原蛋白（Collagen1）等活化生物标志物的表达。将CTL-exo加入到HepGA14培养体系中，qPCR检测HepGA14细胞内HBV DNA、cccDNA及外泌体中HBx mRNA表达水平，Western Blot检测外泌体HBx蛋白表达水平。符合正态分布的计量资料两组间比较采用成组t检验，多组间比较采用单因素方差分析，进一步两两比较采...     

肝癌细胞低氧环境下分泌的外泌体对同源细胞活性的影响

目的探讨肝癌细胞低氧环境下分泌的外泌体对同源细胞活性的影响。方法采用差速超速离心法提取低氧环境下人肝癌细胞(HHCC)分泌的外泌体,通过投射电子显微镜观察外泌体的形态学特征,Western印迹检测外泌体特异性蛋白表达。采用CCK-8检测细胞增殖能力,细胞划痕实验检测细胞迁移能力,Transwell实验检测细胞侵袭能力。结果低氧环境下HHCC分泌的外泌体直径80~130 nm,表达外泌体相关标志蛋白CD9、CD63、CD81。培养48、72 h,外泌体组HHCC的吸光度值明显高于空白对照组(P<0.05)。细胞划痕实验24、48 h,外泌体组细胞迁移距离明显长于空白对照组(P<0.05)。培养48 h,外泌体组侵袭至Transwell小室膜下的HHCC细胞数明显多于空白对照组(P<0.01)。结论低氧环境下HHCC分泌的外泌体能够促进HHCC的增殖、迁移和侵袭。     

肝癌细胞来源外泌体对肿瘤相关M2型巨噬细胞极化的影响

目的 探讨来源于肝癌细胞的外泌体对肿瘤相关巨噬细胞极化的影响，揭示肝癌形成新机制。方法 通过超速离心法分离肝癌细胞来源外泌体，透射电子显微镜、动态光散射粒度分析仪、蛋白免疫印迹法对外泌体表征进行鉴定；诱导巨噬细胞极化模型，实时荧光定量PCR和蛋白免疫印迹法验证其极化状态。符合正态分布的计量资料两组间比较采用t检验；多组间比较采用单因素方差分析，进一步两两比较采用LSD-t检验。结果 透谢电子显微镜显示肝癌细胞来源外泌体为圆形或椭圆形囊泡结构，外泌体粒径大小为(172.65±2.34)nm,蛋白免疫印迹分析显示肝癌细胞来源的外泌体中标志蛋白TSG101和CD63呈高阳性表达。佛波酯15 ng诱导人源单核细胞巨噬细胞24 h贴壁后CD68表达显著增加(6.67±0.98 vs 1.00±0.25,t=11.20,P<0.001)。蛋白免疫印迹分析显示，相比对照组(L02来源外泌体组),HCC细胞来源外泌体(低、中、高3种剂量)诱导巨噬细胞表达M2型巨噬细胞标志物Arg-1、CD163均明显增加(P值均<0.05)。结论 肝癌细胞来源外泌体可促进巨噬细胞M2型极化。     

外泌体miR-155调控p38丝裂原活化蛋白激酶信号通路影响心肾综合征大鼠的心肾细胞凋亡

目的:基于外泌体miR-155调控p38丝裂原活化蛋白激酶(p38MAPK)信号通路影响心肾综合征(CRS)大鼠的心肾细胞凋亡探讨CRS的发病机制。方法:SD大鼠分为空白组、造模3周组、造模4周组、造模5周组、造模6周组,每组10只,以生理盐水或阿霉素腹腔注射造模。心脏超声检测心功能,ELISA法检测血清氨基末端脑钠肽前体(NT-proBNP)、肾损伤分子1,全自动生化仪检测血清肌酐、尿素氮,EXOQuick试剂盒提取血浆外泌体,用ELISA试剂盒对血浆外泌体定量检测,RT-PCR法检测心肾组织p38MAPK mRNA、心肾组织miR-155、外泌体miR-155的表达,Western-Blot法检测心肾组织p38MAPK及磷酸化p38MAPK(p-p38MAPK)的表达,HE染色观察组织形态学改变,TUNEL法检测心肾细胞凋亡率。结果:造模后各组大鼠心肾功能降低;与空白组比较,造模4周组、5周组心脏p-p38MAPK表达增高(P0.05),6周组p-p38MAPK表达增高(P0.01);造模4周组、5周组、6周组肾脏p-p38MAPK表达增高(P0.01);造模3周组、4周组、5周组、6周组心脏、肾脏细胞凋亡率增高(P0.01);造模4周组、5周组、6周组血浆外泌体含量降低(P0.01);造模3周组、4周组、5周组、6周组外泌体miR-155表达降低,心肾组织miR-155表达降低(P0.01)。结论:p-p38 MAPK在CRS大鼠心肾细胞凋亡中起着关键作用,且外泌体miR-155可能对其有着调控作用。     

Three layer functional model and energy exchange concept of aging process

Relying on a certain degree of abstraction, we can propose that no particular distinction exists between animate or living matter and inanimate matter. While focusing attention on some specifics, the dividing line between the two can be drawn. The most apparent distinction is in the level of structural and functional organization with the dissimilar streams of ‘energy flow’ between the observed entity and the surrounding environment. In essence, living matter is created from inanimate matter which is organized to contain internal intense energy processes and maintain lower intensity energy exchange processes with the environment. Taking internal and external energy processes into account, we contend in this paper that living matter can be referred to as matter of dissipative structure, with this structure assumed to be a common quality of all living creatures and living matter in general. Interruption of internal energy conversion processes and terminating the controlled energy exchange with the environment leads to degeneration of dissipative structure and reduction of the same to inanimate matter, (gas, liquid and/or solid inanimate substances), and ultimately what can be called ‘death.’ This concept of what we call dissipative nature can be extended from living organisms to social groups of animals, to mankind. An analogy based on the organization of matter provides a basis for a functional model of living entities. The models relies on the parallels among the three central structures of any cell (nucleus, cytoplasm and outer membrane) and the human body (central organs, body fluids along with the connective tissues, and external skin integument). This three-part structural organization may be observed almost universally in nature. It can be observed from the atomic structure to the planetary and intergalactic organizations. This similarity is corroborated by the membrane theory applied to living organisms. According to the energy nature of living matter and the proposed functional model, the decreased integrity of a human body's external envelope membrane is a first cause of the structural degradation and aging of the entire organism. The aging process than progresses externally to internally, as in single cell organisms, suggesting that much of the efforts towards the restoration and maintenance of the mechanisms responsible for structural development should be focused accordingly, on the membrane, i.e., the skin. Numerous reports indicate that all parts of the human body, like: bones, blood with blood vessels, muscles, skin, and so on, have some ability for restoration. Therefore, actual revival of not only aging tissue of the human body's membrane, but the entire human body enclosed within, with all internal organs, might be expected. We assess several aging theories within the context of our model and provide suggestions on how to activate the body's own anti-aging mechanisms and increase longevity. This paper presents some analogies and some distinctions that exist between the living dissipative structure matter and inanimate matter, discusses the aging process and proposes certain aging reversal solutions.     

Unusual responses of nocturnal pineal melatonin synthesis and secretion to swimming: Attempts to define mechanisms

Abstract: The effect of swimming at night on rat pineal melatonin synthesis was compared with that of light exposure at night. Rats were forced to swim at 0030 hr (lights out at 2000 hr) and sacrificed by decapitation 15 and 30 min later, immediately after swimming. Other groups of animals were exposed to white light (650μW/cm²) for 15 and 30 min at same time. Swimming caused a rapid and highly significant drop in the melatonin content in the pineal gland; however, the activity of N-acetyltransferase (NAT), the supposed rate limiting enzyme in the melatonin production, was not changed. Despite the drop in pineal melatonin levels, serum concentrations of the indole remained elevated in the rats that swam. In contrast, melatonin levels in the pineal and serum of light exposed rats fell precipitously, accompanied by a significant suppression of NAT activity. Since we anticipated that the strenuous exercise associated with swimming may induce release of artrial natriuretic peptide (ANP) from the heart, which in turn could cause the release of pineal melatonin, in a second study we injected physiological saline intravenously to stretch the cardiac muscle and release ANP. Three milliliters of normal saline was injected during the day into the jugular vein of anesthetized rats that were pretreated with isoproterenol to stimulate pineal melatonin production. Animals were killed 15 min after the saline injection, and pineal NAT activity and pineal melatonin levels were measured. The saline injections caused no alteration in the elevated levels of either NAT or melatonin. These data suggest that the disparity in pineal NAT activity (which was high) and pineal melatonin (which was low), in animals swum at night, may not be caused by ANP which is released during strenuous exercise such as swimming.     

Melatonin and photoperiodic time measurement: Seasonal breeding in the sheep

Abstract: Well-established circadian physiology supports the view that photoperiodic time measurement utilizes the coincidence between the presence of light and a photosensitive phase of a 'biological clock' to alter reproductive status—the so-called external coincidence model of seasonal breeding. In this review, we examine the mechanism whereby photoperiod interacts with presumed suprachiasmatic nuclei activity to allow endogenous melatonin to normally synchronize reproductive activity to the optimal time of year. The Romney Marsh sheep is particularly explored as an experimental model. It is suggested that the on/off activity of seasonal reproduction may be a robust mechanism able to be predictably manipulated by the judicious use of the light/dark cycle and exogenous melatonin, but firmly based on circadian principles.     

Serological survey of HIV and syphilis in pregnant women in Madagascar

Objectives Peripartal transmission of human immunodeficiency virus (HIV) and Treponema pallidum, the causative agent of syphilis, leads to severe consequences for newborns. Preventive measures require awareness of the maternal infection. Although HIV and syphilis testing in Madagascar could be theoretically carried out within the framework of the national pregnancy follow‐up scheme, the required test kits are rarely available at peripheral health centres. In this study, we screened blood samples of pregnant Madagascan women for HIV and syphilis seroprevalence to estimate the demand for systemic screening in pregnancy. Methods Retrospective anonymous serological analysis for HIV and syphilis was performed in plasma samples from 1232 pregnant women that were taken between May and July 2010 in Ambositra, Ifanadiana, Manakara, Mananjary, Moramanga and Tsiroanomandidy (Madagascar) during pregnancy follow‐up. Screening was based on Treponema pallidum haemagglutination tests for syphilis and rapid tests for HIV, with confirmation of positive screening results on line assays. Results Out of 1232 pregnant women, none were seropositive for HIV and 37 (3%) were seropositive for Treponema pallidum. Conclusions Our findings are in line with previous studies that describe considerable syphilis prevalence in the rural Madagascan population. The results suggest a need for screening to prevent peripartal Treponema pallidum transmission, while HIV is still rare. If they are known, Treponema pallidum infections can be easily, safely and inexpensively treated even in pregnancy to reduce the risk of transmission.     

Variabilité des concentrations plasmatiques de l’angiotensinogène et risque d’hypertension artérielle chez le rat transgénique

Aim

Genetic polymorphisms of the human angiotensinogen gene are frequent and may induce up to 30% increase of plasma angiotensinogen concentrations with a blood pressure increase of up to 5 mmHg. Their role for the pathogenesis of human arterial hypertension remains unclear. High plasma angiotensinogen levels could increase the sensitivity to other blood pressure stressors.

Methods

Male transgenic rats with a 9-fold increase of plasma angiotensinogen concentrations and male non-transgenic rats aged 10 weeks were treated or not with NG-Nitro-L-arginine-methyl ester for 3 weeks in their drinking water (n = 3/group). Systolic blood pressure and body weight were measured at baseline and at the end of the study when left ventricular weight and ventricular expression of angiotensin I-converting enzyme and procollagen Iα1 were determined (polymerase chain reaction).

Results

At baseline, transgenic rats had +18 mmHg higher bood pressure and –8% lower body weight compared to non-transgenic rats (P < 0.05) without significant changes for the vehicle groups throughout the study (P > 0.05). NG-Nitro-L-arginine-methyl ester increased blood pressure, left ventricular weight and left ventricular weight indexed for body weight by +41%, +17.6% and +18.6% (P < 0.05) in transgenic and +25%, +5.3% and +6.7% (P > 0.05) in non-transgenic rats compared to untreated animals, respectively. Cardiac gene expression showed no differences between groups (P > 0.05).

Conclusion

Increased plasma angiotensinogen levels may sensitize to additional blood pressure stressors. Our preliminary results point towards an independent role of angiotensinogen in the pathogenesis of human hypertension and associated end-organ damage.     

Morphological and immunocytochemical heterogeneity of cultured pinealocytes from one-week-and two-month-old rats: Planimetric and densitometric investigations

Abstract: In vitro preparations of rat pinealocytes are widely used for biochemical analyses of signal transduction processes. This paper deals with morphological and immunocytochemical features of such preparations. Special attention was paid to the problems of whether pinealocytes represent a heterogeneous cell population and how such heterogeneity may develop during ontogeny. The investigations were performed with cells which were obtained from the pineal organ of one-week-and two-month-old rats, attached to synthetic peptide-coated coverslips or tissue culture chamber slides, and maintained under in vitro conditions overnight. The attached cells were then fixed with paraformaldehyde. These preparations yielded monolayers of spherical cells of different sizes; most cells were isolated, but some of them were aggregated and formed small clusters. On the average, the cells from the one-week-old animals were smaller than the cells from the two-month-old animals. Immunocytochemical demonstration of S-antigen, a pinealocyte-specific marker, showed that the majority of the cells from two-month-old animals were intensely or moderately labelled. Pinealocytes from one-week-old animals were less S-antigen immunoreactive. Only very few cells (less than 1% displayed glial fibrillary acidic protein (GFAP)-immunoreactivity. Planimetric investigations of the cell size and semiquantitative densitometric investigations of the intensity of the S-antigen immunoreaction revealed that (i) pinealocytes kept in vitro form a heterogeneous cell population, and that (ii) this heterogeneity increases during postnatal development from one-week-old to two-month-old animals. Two groups of pinealocytes can be distinguished based on their developmental fate: pinealocytes of one group grow dramatically, but show only a moderate increase in S-antigen immunoreactivity, and pinealocytes of the other group retain their size, but display a distinct increment in S-antigen immunoreacti vitv.     

Effects of pinealectomy and melatonin administration on certain indices of ovarian hyperplasia and/or hypertrophy in rats with both ovaries intact or after unilateral ovariectomy

Abstract: In earlier studies from other laboratories it was shown that melatonin decreased ovarian weight in rats and inhibited compensatory hypertrophy of the remaining ovary after unilateral ovariectomy. This study was designed to examine the influence of melatonin on certain indices of ovarian hyperplasia and/or hypertrophy in adult female rats with both ovaries preserved and with either an intact pineal gland or with the pineal gland removed (pinealectomy, PX) or, finally, in sham-PX animals. Similar studies were conducted on rats after unilateral ovariectomy, referring the examined parameters to the remaining intact ovary. The studies included mitotic activity of granulosa layer cells and corpus luteum cells, ovarian weight, ovarian cross-sectional area, cross-sectional area of the granulosa layer of all the Graafian follicles and the cross-sectional areas of the corpora lutea, visible on the ovarian cross-section. On the basis of results, we conclude that: 1) the effect of PX on the processes of ovarian hyperplasia and hypertrophy may vary; analogously, exogenous melatonin administration may influence ovarian hyperplasia and hypertrophy in different ways; 2) PX and exogenous melatonin may, under certain conditions, exert similar biological effects, even synergistic effects; 3) melatonin inhibits ovarian growth processes, while the effects of PX are variable; 4) the results indicate that in experiments performed on rats, with the use of two control groups, i.e., intact and sham-PX, melatonin effects on these two groups may differ.