Mechanisms by which mastitis affects reproduction in dairy cow: A review.

Reproductive performance is a key factor in determining the profitability of dairy farm, which is affected by many factors such as environment and diseases. Mastitis is a common and important disease, which has caused huge economic losses to the dairy industries worldwide. Mammary gland infection causes immune responses, resulting in the abnormal secretion of cytokines and hormones and abnormal function of the reproductive system such as the ovary, corpus luteum, uterus and embryo. Cows with mastitis have delayed oestrus, decreased pregnancy rate and increased risk of abortion. The adverse effects of mastitis on reproductive performance are affected by many factors, such as occurrence time, pathogen and cow factors. This paper primarily reviews the progress in the effects and mechanisms of mastitis on reproductive performance, with emphasis on maternal transcriptome, genomic analysis, epigenetic modification, microbiota, inflammatory regulation and immune evasion mechanism of mastitis, aiming to provide directions for the prevention and control of mastitis in the future.

Effective and economical column-based method for RNA isolation from animal cells.

OBJECTIVES: To develop an efficient, economical, and low-toxicity method for the extraction of RNA from animal cells to meet a basic requirement of biological research: the isolation of high-quality RNA. RESULTS: Guanidine hydrochloride was used as a lysis buffer and Na-acetate was used as a wash buffer to extract RNA fragments from TM3 Leydig cells and ovarian granulosa cells efficiently. The functionality of the extracted RNA samples was verified through polymerase chain reaction (PCR) and real-time fluorescence quantitative PCR (RT-PCR). PCR results showed that the normal DNA column-based method could guarantee RNA integrity and could be used to amplify gene fragments successfully. RT-PCR analysis showed that the RNA samples isolated through the proposed method could be used to detect the expression levels of steroidogenic acute regulatory protein and hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 1 mRNA in TM3 Leydig cells under induction by luteinizing hormone. The proposed method could be used to isolate RNA from mammalian cells and provided RNA yields of > 120 ng/5 × 106 cells. This method provided RNA with purities and yields that are sufficient for cDNA synthesis and PCR amplification in gene expression studies. CONCLUSIONS: The proposed RNA extraction method has the advantages of low toxicity, safe handling, and low cost. Isolation can be completed in 20 min. The proposed method can be used to extract RNA from various animal cell samples and is worth promoting.