Impact of bone marrow mesenchymal stem cells on the submandibular gland structure of adult male albino rats exposed to cadmium chloride toxicity

Objective: This study was carried out in submandibular salivary glands of rats to demonstrate the changes induced by cadmium intoxication and the possible prophylactic and therapeutic effects of bone marrow mesenchymal stem cells (BMSCs).Design: Sixty-five rats were divided into five groups. Rats in Group I were controls while those of Group II received daily dose of 10 mg/kg cadmium for 24 days. Rats in Group III received single prophylactic dose of 1 x 106 BMSCs one week before cadmium administration. Rats of Group IV were concomitantly administered cad-mium and BMSCs, while those of Group V received cadmium for 24 days and were then treated with single dose of 1 x 106 BMSCs. Rats of Groups I, II, III, and IV were euthanized at the end of the experiment while those of Group V were euthanized one week later. Salivary gland specimens were processed and stained with H&E and inducible nitric oxide synthase; other specimens were used to demonstrate metallothionein gene expression using RT-PCR, malondialdehyde and catalase enzymes were detected by ELISA.Results: Groups III and IV had nearly comparable findings to Group I regarding histological pattern with normal gland features. Group III recorded a lower fold of change for metallothionein gene (1.14 +/- 0.20), a lower malondialdehyde enzyme (21.67 +/- 1.63 nmol/mg), and a higher catalase enzyme (66.33 +/- 2.16 mmol/mg). Regarding all variables, significant differences were found between the different groups (P < 0.001).Conclusion: BMSCs have prophylactic and therapeutic effects against cadmium-induced cytotoxicity in rat sali-vary glands.