Objective  To study the protective effect of Pinus massoniana pine needle extract (PMNE) on cadmium chloride-induced cytotoxicity in human bronchial epithelial cells (16HBE).

  Methods  Ethanol extraction method was used to prepare PMNE. The 16HBE cells of low-, moderate-, and high-dose groups were treated with 1, 100, and 500 μg/mL PMNE for 6 hours; then the 16HBE cells were exposed to 25 μmol/L cadmium chloride (CdCl₂) for 48 hours. A negative control group (normally cultured 16 HBE cells) and a blank control group (culture medium only) were also established. Cell Counting Kit-8 (CCK8) method was used to detect relative survival rate of the cells. Thiobarbituric acid (TBA) method was adopted to measure intracellular content of malondialdehyde (MDA). Quantitative PCR (qPCR) was applied to determine relative cellular expressions of apoptosis-related genes of B cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein.

  Results  Compared with that of negative control cells, the relative survival rate of cells treated with CdCl₂ alone was decreased significantly (P < 0.05) but the intracellular MDA expression was increased (P < 0.05). The relative survival rate of the cells treated with low-, moderate-, and high-dose PMNE were increased but the intracellular MDA of the cells was decreased, both in a significant dose-response manner, in comparison with those of the cells treated with CdCl₂ alone significantly (P < 0.05 for all). Significantly increased relative expression of anti-apoptotic gene Bcl-2 and decreased relative expression of pro-apoptotic gene Bax, both in a significant dose-response manner, were observed in the cells with low-, moderate-, and high-dose PMNE treatment in contrast to those of the cells treated with CdCl₂ alone (all P < 0.05).

  Conclusion  Ethanol extract of Pinus massoniana pine needles has a certain protective effect against chloride-induced cytotoxicity in human bronchial epithelial cells in vitro.