Protective effects of salvia miltiorrhiza polyphenols acid on gingival tissues of the rats under sustained high + Gz exposure

Abstract

Objective To investigate changes in gingival tissues of the rats in sustained + Gz acceleration exposure and the protective effects of salvia miltiorrhiza polyphenols acid. Methods Twenty-seven male SD rats were randomly divided into negative control, + 5 Gz positive control, + 5 Gz dose group (low, moderate, and high dose), + 10 Gz positive control and + 10 Gz dose group (low, moderate, and high dose) groups. Except negative control group, other groups were exposed to + 5 Gz or + 10 Gz for 30 s with 60 s intervals, 5 times a day, 4 days a week for 3 consecutive weeks. Salvia miltiorrhiza polyphenols acid was injected into rat's abdomen with the different doses (2, 6, 18 mg/kg) 30 min before each exposure. Three control groups were injected equivalent amount of 0.9% sodium chloride solution. The rat's behavior and gingival tissues changes were observed after the experiments. Real time PCR was applied to determine the relative expression of heat shock protein 70 (HSP70) mRNA in gingival tissues. Results Sustained high + Gz exposure influenced the active degree of model rats in a certain range and salvia miltiorrhiza polyphenols acid helped the rats turning to the activity recovery. The gingival tissues of every groups showed red, sheen and with firm and tenacious character, and no obvious plumping and bleeding were observed. The epithelium of gingival tissues of negative control group kept its integrity, but the epithelium of + 5 Gz positive control and dose groups showed significant keratinization and granular layer. Situations were more serious for + 10 Gz positive and + 10 Gz dose groups. The relative expression of HSP70 mRNA was increased with the growing of + Gz level (F=169.22, 650.69, P<0.01), but showed significant restraint with the augment of salvia miltiorrhiza polyphenols acid dose (F=68.73, P<0.01). Conclusions The relative expression of HSP70 mRNA in gingival tissues of rats is positively correlated to + Gz level. The higher + Gz level the more harmful to the gingival tissues of rats. Salvia miltiorrhiza polyphenols acid has certain protective effect on the gingival tissues of rats. Key words: Acceleration; Rats; Gingiva; HSP70 heat-shock proteins; Salvia miltiorrhiza polyphenols acid