Abstract: 【Abstract】 Objective To investigate the effect of different concentrations and infection durations of varicella-zoster virus （VZV） on nucleotide-binding and oligomerization domain-like receptor protein 3 （NLRP3） inflammasome-related proteins in mouse brain astrocytes. Methods Mouse brain astrocytes were infected with different dilutions （100 ［undiluted original concentration］- 10-7） of cell-free VZV suspension, and the cytopathic effect was observed under a microscope in each group to determine the concentration and infection duration of VZV for subsequent experiments. Some mouse brain astrocytes were infected with cell-free VZV suspension at dilutions of 100, 10-2, 10-4, and 10-6, and samples were collected on day 5; some other mouse brain astrocytes were infected with cell-free VZV suspension at the median tissue culture infective dose （TCID50） of 1.0 × 105/ml, and the samples were collected on days 3, 5, 7, and 9, separately; normally cultured mouse brain astrocytes served as control groups in the above experiments. Western blot analysis was performed to determine the protein expression of VZV glycoprotein E （gE）, NLRP3, caspase-1, and interleukin-1β （IL-1β） in mouse brain astrocytes in each group. One-way analysis of variance was used for comparisons of data with a normal distribution, and least significant difference-t test was used for multiple comparisons. Results On day 3 after infection with VZV at the dilution of 100, the number of cells decreased, some cells became irregular, lost their original shapes, and showed granular cytoplasm and an unclear nucleus structure, while some cells fused and formed multinucleated giant cells; on day 5, ≥ 50% of cells showed the aforementioned changes and some intercellular spaces were dilated giving a network-like appearance in the 100-dilution group; on day 9, the 100- - 10-6- dilution groups all showed dilated intercellular spaces arranged in networks and cytopathic effect in ≥ 50% of cells; on day 10, some cells in the control group exhibited cytoplasmic vacuolation, exfoliation and flotation. Based on these results, the following experiments were conducted with VZV at a concentration gradient ranging from 100 to 10-6 dilutions, and the observations were performed from day 3 to day 9. Western blot analysis showed increased protein expression of VZV gE, NLRP3, caspase-1, and IL-1β in the VZV infection groups compared with the control group, and there were significant differences among different VZV concentration groups （F = 21.45, 43.82, 21.85, 29.53, respectively, all P < 0.05） and different infection duration groups （F = 224.10, 78.79, 186.50, 85.08, respectively, all P < 0.05）. With the increasing dilution ratios, the expression of inflammasome-related proteins （NLRP3, caspase-1, and IL-1β） decreased, with the highest expression observed in the 100-dilution group and the lowest in the 10-6-dilution group （all P < 0.05）. On days 3, 5, and 7 after VZV infection, the expression of NLRP3 inflammasome-related proteins increased over time, with the highest expression observed on day 7 and the lowest on day 3 （all P < 0.05）, while their expression decreased on day 9. Conclusion The expression of NLRP3 inflammasome-related proteins was up-regulated in mouse brain astrocytes after VZV infection, and their expression levels increased along with the increase in the VZV concentration and infection duration in a certain range.

Key words: Herpesvirus 3, human, Astrocytes, Nod-like receptor protein 3, Caspase 1, Interleukin-1 beta