Establishment and characterization of a murine HSV-2 model for the evaluation of a novel microbicide

Abstract

Herpes simplex virus −2 (HSV-2) is a serious global epidemic with an estimated 400 million people infected and about 20 million cases reported annually. The prevalence in South Africa is at 31% in females aged 15–29 years old. Microbicides are self-administered topical agents which provide women-controlled protection against sexually transmitted infections (STIs). There is an urgent need for microbicides which not only inhibit HSV-2 and other STIs but also reduce the risk of HIV contraction. There is a lack of in vivo models to evaluate the safety and efficacy of novel microbicides, hence this study aims to provide an HSV-2 challenge model which can be used to evaluate the safety and efficacy of novel microbicides. Safety assessment of the microbicide was done at 500 μg/mL in male and female Balb/c mice (n = 8) and were inoculated intrarectally and intravaginally respectively. Rectal and vaginal tissue samples were collected 2 h post-inoculation for histology. For model establishment, 1×06 PFU of the HSV-2 strain G virus was used. In the efficacy of the microbicide, male and female mice (n = 10) were inoculated with 10 μl microbicide 10 min before being inoculated with the virus and the control group were inoculated with sterile phosphate buffered saline. The experiments were conducted in a BSL3 lab. The mice were monitored for infection twice a day over 10 days. Histological analysis showed that the microbicide was safe to use as there were no signs of tissue damage. The amounts of virus used was sufficient to induce a definite infection within 8 days. Application of the novel microbicide delayed mortality rate in the challenge group up to day 19 in both male and female groups compared to day 8 in the control group. Balb/c mice are highly susceptible to the HSV-2 virus and are an appropriate model for microbicide studies