Effects of transport and storage conditions on the nucleic acid detection for three kinds of mouse RNA viral samples / 中国比较医学杂志

Objective To analyze the effect of transport and storage conditions on the detection of pathogenic nucleic acid MHV, Reo-3, MNV in laboratory mouse cecal contents samples. Methods MHV, Reo-3 and MNV were mixed with mouse cecal contents and used as reference samples,respectively. They were placed in the lysis buffer of RNA extraction reagent(buffer AVL)or normal saline, and stored at 4℃ and room temperature(22℃-25℃). RNA of these samples was extracted at 1,2,3,7,and 14 days. Then the amount of nucleic acid in samples was detected by real-time fluorescence quantitative PCR. Results A greater decrease of the amount of nucleic acid was observed when the samples were placed in normal saline than that kept in buffer AVL. The amount of nucleic acid in samples stored at 4℃ was found to be higher than that stored at 25℃ room temperature. The amount of nucleic acid in the samples which were kept in buffer AVL at 4℃ for 3 days was higher than 50%,still detectable in the samples kept for 7 days,and undetectable at 14 days. Conclusions Mouse cecal content samples are preferably stored in the lysis buffer of RNA extraction reagent and transported at 4℃ for the detection of MHV, Reo-3, and MNV nucleic acid. It is better to complete the detection test within 3 days.

Dynamic changes of viral loads and antibody responses in ICR mice naturally infected with hepatitis virus / 中国比较医学杂志

Objective To define dynamic changes of viral loads and antibody responses in ICR mice naturally infected with hepatitis virus in an MHV contaminative facility .Method A total 50 ICR were housed by different “dirty bedding” exposure.Antigen and antibody was detected after 2,4,8,14,21,28,35,42,56 and 84 days.Result Mouse hepatitis virus (MHV) was detected in lung after 2 days, and positive rate is 20% (1/5).MHV was detected in lung, liver, cecal and feces during 4 and 56 days.The positive rate was 0/5 in lung, liver, cecal and feces on 84 days after experiments.Antibody positive rates were 100%during 8 and 84 days.Conclusion Serological method can be used as the main method for the diagnosis of the daily supervision , and antigen detection method can only be applied to early diagnosis .