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MicroRNAs (miRNA) are important regulators of oocyte maturation, playing a key role in modulating gene expression both in a temporal- and spatial-specific manner. These small non-coding RNAs are involved in important processes during oocyte maturation, acting as messengers between the oocyte and its surrounding cumulus cells. Despite its significance, the bidirectional communication mechanism is still unknown. To test miRNA communication between oocyte and surrounding cumulus cells through the gap junctions the gap junctions were either blocked with carbenoxolone or not. MiRNA sequencing of oocytes at 1, 6, and 22 h of in vitro maturation was then performed. Among the differentially expressed miRNAs, bta-miR-21-5p, a regulator of cumulus cell viability and oocyte maturation, was the only previously known miRNA. Furthermore, by labeling a bta-miR-21-5p mimic with FAM, crossing of this miRNA through the gap junctions within the cumulus-oocyte complex could be visualized and internalization in the oocyte was confirmed by RT-qPCR. In conclusion, this study provides, for the first time, evidence that miRNA communication within the bovine cumulus-oocyte complex is enabled through the gap junctional network. [ABSTRACT FROM AUTHOR]

The objective was to determine the effect of ageing on plasma steroid concentrations and testicular volume, echotexture and haemodynamics in Ossimi rams. Twenty‐four rams were allocated, by age, into three groups: young (1 year; 32.00 ± 0.78 kg, n = 6); mature (2.5 years; 48.00 ± 1.02 kg, n = 9) and aged (7.5 years; 65.00 ± 1.10 kg, n = 9). Aged rams had the highest (p ˂ 0.05) plasma testosterone concentrations 3.90 ± 0.75 ng/ml (three‐fold the other groups), whereas in young rams, plasma estradiol‐17β concentrations (5.85 ± 0.34 pg/ml) were approximately one‐quarter (p ˂ 0.05) of other groups. Regarding pulsed‐wave Doppler indices values of the (resistive index RI; and pulsatility index PI) were lower (p ˂ 0.05) in the mature (0.32 ± 0.04 and 0.36 ± 0.03, respectively) and aged (0.51 ± 0.03 and 0.77 ± 0.06) rams compared to young rams (0.62 ± 0.03 and 0.98 ± 0.07). In the young group, testicular pixel intensity was highest (p ˂ 0.05) but values of coloured area/pixels were lowest (p ˂ 0.05) compared to the other groups. In conclusion, these parameters indicate that aged rams (7.5 years) are likely to be suitable for breeding ahead of the younger aged groups (1 and 2.5 years) examined, but a final decision would need to be tempered by consideration of other parameters in the breeding soundness examination (BSE), such as physical soundness and semen characteristics. Of the parameters studied, testicular pixel intensity could be most readily incorporated in a BSE for deciding a ram's breeding efficiency. [ABSTRACT FROM AUTHOR]

The current study aimed to measure the testicular ultrasonographic dimensions (length, width, thickness and volume) as well as spectral Doppler indices (resistive index and pulsatility index) of testicular artery, and to investigate the possible differences between the paired testes based on testicular dimensions and blood flow Doppler indices. Five Awassi rams of normal fertility, with a body weight 50-65 kg and aged 3-5 years were subjected to testicular ultrasound examination for testicular dimensions and pulsed-wave Doppler, twice monthly for five consecutive months. The testicular volume of the left testis (69.34±6.66 mm3) was higher than the right testis (66.85±5.46 mm3). Testicular thickness was significantly affected by the laterality of the testes (P<0.05). Doppler measures for RI (resistive index) as well as pulsatility index (PI) were slightly higher (P>0.05) in the right testicular artery rather than the left one. In conclusion, the testicular ultrasound measures and Doppler flow indices varied between the paired right and left testes in mature rams. In addition, the blood flow indices are highly correlated in the testicular artery of rams. [ABSTRACT FROM AUTHOR]