The effects of repeated freezing and thawing on bovine sperm morphometry and function.

Refreezing the remaining genetic resources after in vitro fertilization (IVF) can conserve genetic materials. However, the precise damage inflicted by repeated freezing and thawing on bovine sperm and its underlying mechanism remain largely unexplored. Thus, this study investigates the impact of repeated freeze-thaw cycles on sperm. Our findings indicate that such cycles significantly reduce sperm viability and motility. Furthermore, the integrity of the sperm plasma membrane and acrosome is compromised during this process, exacerbating the advanced apoptosis triggered by oxidative stress. Additionally, transmission electron microscopy exposed severe damage to the plasma membranes of both the sperm head and tail. Notably, the "9 + 2" structure of the tail was disrupted, along with a significant decrease in the level of the axonemal protein DNAH10, leading to reduced sperm motility. IVF outcomes revealed that repeated freeze-thaw cycles considerably impair sperm fertilization capability, ultimately reducing the blastocyst rate. In summary, our research demonstrates that repeated freeze-thaw cycles lead to a decline in sperm viability and motility, attributed to oxidative stress-induced apoptosis and DNAH10-related dynamic deficiency. As a result, the utility of semen is compromised after repeated freezing.

The complete chloroplast genome of Cuscuta australis R. Br. (Convolvulaceae) and its phylogenetic implication.

The genus Cuscuta (Convolvulaceae) is an annual parasitic twining herb. There are about 200 species in this genus, which are widely distributed in tropical and subtropical areas. Cuscuta is mainly parasitic on crops bringing significant losses to the production of agriculture. Furthermore, dried seeds of C. chinensis and C. australis are used as a Chinese traditional herbal medicine. Despite the importance of Cuscuta species, it is difficult to distinguish these plants by the naked eye. Moreover, plastid sequence information available for Cuscuta species is limited. In this study, the complete chloroplast (cp) genome sequence of C. australis was determined using next-generation sequencing. The entire cp genome was determined to be 85,263 bp in length. It contained large single-copy (LSC) and small single-copy (SSC) regions of 50,384 and 6727 bp, respectively, which were separated by a pair of 14,076 bp inverted repeat (IR) regions. The genome contained 98 genes, including 61 protein-coding genes, 29 tRNA genes, and 4 rRNA genes. The overall GC content of the genome is 37.8%. A phylogenetic tree reconstructed by 26 chloroplast genomes reveals that C. australis is most related with Cuscuta pentagona in Convolvulaceae, with bootstrap support values of 100%.

MR diffusion weighted imaging for evaluation of radiotherapeutic effects on rabbit VX2 tumor model.

OBJECTIVE: To investigate the feasibility of magnetic resonance (MR) diffusion weighted imaging (DWI) for evaluation of radiotherapeutic effects on rabbit VX2 tumor model. METHODS: Sixteen New Zealand white rabbits received a subcutaneous implantation of VX2 tumor cell suspension 0.5 mL (4 x 10(7) cells/mL) in their right thighs to set up tumor model. And 2 weeks later they were randomly divided into therapy group (Group T, n = 10) and control group (Group C, n = 6). Group T received radiotherapy at a single dose of 10 Gy. MR imaging (MRI) scan including short TI inversion recovery echo-planar imaging DWI, T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI) sequences were performed 1 day prior to as well as 1 day, 2 days, 3 days and 7 days after radiotherapy. Group C received only MRI scan at the same time points without any treatment. MRI appearance on T2WI, T1WI, and DWI images was compared and tumor volume was calculated. Apparent diffusion coefficient (ADC) values of the tumor were evaluated in all cases. HE staining was used for pathological study. RESULTS: Necrosis (n = 8) and hemorrhage (n = 2) were seen gradually on T2WI and T1WI images of Group T after time point of day 2 after irradiation. In Group C, no obvious necrosis was found until day 7. There was no significant difference in tumor volume between the two groups before radiotherapy. After radiotherapy, tumors in Group T showed a gradual growth but not as obvious as Group C. There was a significant difference in tumor volume between the two groups from day 2 on (P < 0.05). ADC value changed dramatically right from the 1st day after radiotherapy in Group T [(0.99 +/- 0.15) x 10(-3) mm2/s for 1 day before radiotherapy, (1.23 +/- 0.08) x 10(-3), (1.45 +/- 0.07) x 10(-3), (1.63 +/- 0.06) x 10(-3), and (2.02 +/- 0.18) x 10(-3) mm2/s for day 1, 2, 3, and 7]; and ADC value had no significant changes after radiotherapy in Group C except day 7 [(1.07 +/- 0.08) x 10(-3) mm2/s for 1 day before radiotherapy, (1.03 +/- 0.04) x 10(-3), (1.05 +/- 0.02) x 10(-3), (1.05 +/- 0.05) x 10(-3), and (0.95 +/- 0.07) x 10(-3) mm2/s for day 1, 2, 3, and 7]. There was significant difference in ADC value between the two groups for each time point after radiotherapy (P < 0.01). Pathological study showed that the number of viable tumor cells in Group T decreased 1 day after radiotherapy, and the inflammatory cell infiltration was marked and almost all viable tumor cells disappeared by day 7 after radiotherapy. CONCLUSIONS: DWI is a new promising technique for monitoring radiotherapy outcomes. ADC value may give a prior clue on physiological changes of radiotherapy before routine MRI could tell.

Levonorgestrel implants enhanced the suppression of spermatogenesis by testosterone implants: comparison between Chinese and non-Chinese men.

CONTEXT: Previous male contraceptive studies showed that progestins enhance spermatogenesis suppression by androgens in men. OBJECTIVE: We compared the efficacy of spermatogenesis suppression by the combination of levonorgestrel (LNG) with testosterone (T) implants to that by T implants alone in two different ethnic groups. DESIGN: This was a randomized trial performed in two centers with two treatment groups. SETTINGS: The study was performed at the Academic Medical Center in the United States and the Research Institute in China. PARTICIPANTS: Forty non-Chinese and 40 Chinese healthy male volunteers were studied. INTERVENTIONS: Subjects were randomized to receive four LNG implants together with four T implants (inserted on d 1 and wk 15-18) vs. T implants alone for 30 wk. MAIN OUTCOME MEASURES: The primary end point compared the efficiency of suppression to severe oligozoospermia (1 x 10(6)/ml) by LNG plus T implants vs. that by T implants alone. The secondary end point examined differences in spermatogenesis suppression between Chinese and non-Chinese subjects. RESULTS: LNG plus T implants caused more suppression of spermatogenesis to severe oligozoospermia during the treatment period than T implants alone at both sites (P < 0.02). In Chinese men, severe oligozoospermia was achieved in more than 90% of the men in both treatment groups. Suppression to severe oligozoospermia was less in the non-Chinese men (59%) after T alone (P < 0.020); this difference disappeared with combined treatment (89%). T implant extrusion occurred in six men. Acne and increased hemoglobin were the most common adverse events. CONCLUSION: T implants resulted in more pronounced spermatogenesis suppression in Chinese men. Addition of LNG implants to T implants enhanced the suppression of spermatogenesis in the treatment period in both Chinese and non-Chinese men.