Effect of testosterone replacement therapy and mate tea (Ilex paraguariensis) on biochemical, functional and redox parameters of saliva in orchiectomized rats

Objective: Evaluate the effects of testosterone replacement therapy (TRT) and mate tea (MT) [Ilex paraguariensis] on biochemical, functional, and redox parameters of saliva in orchiectomized rats (ORX) Design: Sixty young adult male Wistar rats (3 months old) were either castrated bilaterally or underwent fictitious surgery (SHAM) and were distributed into 5 groups: SHAM, ORX, TU (castrated rats that received a single intramuscular injection of testosterone undecanoate 100 mg/kg), MT (castrated rats that received MT 20 mg/kg, via intragastric gavage, daily), and TU + MT. All treatments started 4 weeks after castration (4 months old) and lasted 4 weeks (5 months old). At the end of treatment, pilocarpine-induced salivary secretion was collected to analyze salivary flow rate (SFR) and biochemistry composition through determination of total protein (TP), amylase (AMY), electrolyte, and biomarkers of oxidative stress. Results: ORX increased SFR, salivary buffering capacity, calcium, phosphate, chloride, total antioxidant capacity, thiobarbituric acid reactive substances (TBARs), and carbonyl protein, reduced TP and AMY activity, and did not change pH, sodium, and potassium compared to SHAM. TU and TU+MT restored all salivary parameters to values of SHAM, while only TBARs and AMY returned to SHAM levels in the MT group. Conclusions: TRT with long-acting TU restored the biochemical, functional, and redox parameters of saliva in orchiectomized rats. Although MT did not have a TRT-like effect on salivary gland function, the more effective reduction in lipid oxidative damage in the MT and TU + MT groups could be considered as adjuvant to alleviate the salivary oxidative stress induced by orchiectomy.