Growing Up Under Constant Light: A Challenge to the Endocrine Function of the Leydig Cells

Abstract

The factors influencing Leydig cell maturity and the acquisition of functional capacity are incompletely defined. Here we analyzed the constant light (LL) influence on Leydig cells’ endocrine function during reproductive maturation. Rats were exposed to LL from P21 to P90. Data were collected at juvenile (P35), peri/pubertal (P42, P49), and adult (P90) stages of life. The results proved the effect of LL on rats’ physiology by changing of bimodal voluntary activity pattern into free-running. Additionally, the peripheral clock in Leydig cells changed in LL condition, indicating disturbed rhythm: the positive element (Bmal1) increased in pre-/pubertal but decreased in the adult period, while negative elements (Per2 and Reverba) were increased. The effects of LL were most prominent in puberty: pituitary genes encoding gonadotropic hormones (Cga, Lhb, Fshb) decreased; serum corticosterone increased, while serum androgens and mass of testicular and sex accessory organs reduced; markers of Leydig cells maturity/differentiation (Insl3, Lhcgr) and steroidogenesis-related genes (Scarb1, Star, Cyp11a1, Cyp17a1) decreased; the steroidogenic and energetic capacity of the Leydig cell mitochondria decreased; the mtDNA copy number reduced, and mitochondrial dynamics markers changed: fusion decreased (Opa1 and Mfn2), and mitophagy increased (Pink1). In adults, the negative effect of LL on mitochondrial function and steroidogenic capacity persists in adult Leydig cells while other parameters reached control values. Altogether, the results indicate that LL slows down Leydig cells’ maturation by reducing the endocrine and energy capacity of cells leading to the delay of reproductive development.

Refractive Index Sensing Based on Multiple Fano Resonances in a Split-Ring Cavity-Coupled MIM Waveguide

“…The effective length of the resonant cavity of FR4 is the largest, and the resonance mode is the lowest, so the sensitivity of FR4 is the largest. The comparison of the sensitivity with other published papers is shown in Table 2 [11,13,14,29,30,32,40].…”

“…Within a certain optical frequency range, quantum interference cancellation occurs between the two states, and the system shows a narrow optical response and high local field enhancement. Fano resonance is very sensitive to geometric parameters and medium environment, which makes it used in sensors [4][5][6], slow light devices [7][8][9][10] and other fields [11][12][13][14]. On the other hand, in the sub-wavelength range, the surface plasmon polaritons (SPPs) can break through the traditional optical diffraction limitation, which brings infinite possibility to the future of photonic devices [15][16][17].…”

Morphofunctional status of interstitial endocrinocytes (Leydig cells) with premature aging caused by dark deprivation

“…Источником тестостерона являются клетки Лейдига, секретирующие данный гормон и расположенные в интерстициальной соединительной ткани семенника. Проводимые исследования показывают негативное влияние светового загрязнения на уровень репродуктивных гормонов и функцию сперматозоидов [3,4] Животные были рандомно разделены на опытные и контрольные группы. Группа негативного контроля -24 животных, которые не подвергались темновой депривации и находились при 12-часовом искусственном свето-темновом освещении.…”