Presence and integration of HBV DNA in mouse oocytes

Abstract

AIM: Hepatitis B is a worldwide public health problem. To explore the feasibility of hepatitis B virus (HBV) vertical transmission via oocytes, the presence and integration of HBV DNA in mouse oocytes were studied. METHODS:Genomic DNA was isolated and metaphases were prepared, respectively from mouse oocytes cocultured with pBR322-HBV DNA plasmids. PCR, Southern blot, dot hybridization and fluorescence in situ hybridization (FISH) were performed to explore the existence and integration of HBV DNA in oocytes. RESULTS:PCR detected positive bands in the tested samples, and then Southern blot revealed clear hybridization signals in PCR products. Final washing solutions were collected for dot hybridization and no signal for HBV DNA was observed, which excluded the possibility that contamination of washing solutions gave rise to positive results of PCR and Southern blot. FISH demonstrated that 36 of 1 000 metaphases presented positive signals.CONCLUSION: HBV DNA sequences are able to pass through the zona and oolemma to enter into oocytes and to integrate into their chromosomes. HBV DNA sequences might be brought into embryo via oocytes as vectors when they are fertilized with normal spermatozoa. [1] . Both chronic hepatitis B and hepatitis C are prevalent among the 12 million Asians and Pacific Islanders living in the USA [2] . It is still a potential risk for public health as a result of immigration from countries with a high prevalence of HBV infection although there is a low incidence rate among the indigenous population in North America and Scandinavian countries [3][4][5] . Chronic active hepatitis and liver cirrhosis are major causes of mortality [1,6] . Moreover, epidemiological studies have clearly shown the importance of HBV in hepatocellular carcinoma (HCC). In China, 500 000 to one million new cases appear every year [1] and 73% of patients with chronic hepatitis and 78% and 71% of those with cirrhosis and HCC, respectively, are HBsAg positive [7] . Therefore, studies on transmission of HBV are of substantial importance in virology as well as in public health.The transmission routes of HBV through blood transfusion [8,9] ; body fluids including serum, saliva, vaginal secretions, breast milk, and semen [10][11][12][13][14] ; intrauterine infection [15,16] ; cell, tissue, and organ transplantation [17,18] and others including hemodialysis units and intravenous drug injection [19][20][21][22][23] have been documented. Hadchouel et al [24] , using molecular hybridization, confirmed the presence of integrated HBV DNA sequences in spermatozoa from two of three patients with HBV infection. They assumed that the presence of integrated sequences in spermatozoa suggested the possibility of true vertical transmission of HBV via the germ line. Using interspecific in vitro fertilization between zona-free hamster ova and spermatozoa from nine patients with HBV infection, we prepared human sperm metaphases for fluorescence in situ hybridization (FISH) with the biotin-labeled full length HBV DNA probe. The...

Nervous Necrosis Virus Replicates Following the Embryo Development and Dual Infection with Iridovirus at Juvenile Stage in Grouper

“…The research on hepatitis B virus has shown that the viral DNA can pass through the zona and oolemma and enter into oocytes by sperm [30], [31]. Furthermore, it was also reported that the virus can be absorbed into the fish sperm and vertically transmitted [32].…”

Infecciones de Transmisión Sexual en Semen: El Hombre como Vector de Transmisión

“…El HBV se ha encontrado en sangre, saliva, leche materna, secreciones vaginales y semen, siendo transmitido principalmente por vía parenteral, sexual y perinatal (Zea-Mazo et al). Se ha determinado secuencias de DNA de HBV en cromosomas de espermatozoides, donde el virus posiblemente ha atravesado la barrera hematotesticular e infectado a la línea germinal masculina y también en oocitos de ratón, lo cual es de gran importancia debido a la posibilidad que el feto pueda adquirir la infección a través de la madre (Huang et al, 2005). En humanos, el virus es detectable en muestras de semen de hombres con hepatitis B aguda así como en el semen de hombres con hepatitis crónica (Leruez-Ville et al, 2005a).…”

Hepatitis B in Pregnancy: Specific Issues and Considerations

“…Approximately one third of HBV infections occur via perinatal transmission [28], and perinatal transmission is the most important vertical transmission route of chronic hepatitis B infection. Perinatal transmission of HBV is mediated via three main modes: 1) Intrauterine transmission; 2) Intrapartum or labour transmission; and 3) Postnatal transmission.…”