Hyperlipidemia is involved in apoptosis in rat submandibular glands.

OBJECTIVE

The aim of the present study was to investigate the effects of hyperlipidemia on histological changes and apoptosis in submandibular glands using apolipoprotein E (apoE)-deficient rats.

DESIGN

Histopathological findings related to induced apoptosis in the submandibular glands were compared between apoE-deficient rats (n=6; male; age, 16 weeks) and the corresponding wild-type rats (n=6).

RESULTS

ApoE-deficient rats showed significantly higher plasma levels of oxidized low-density lipoprotein (LDL), total cholesterol, very LDL and LDL, and lower plasma levels of high-density lipoprotein when compared to control rats (P<0.05). Lipid deposition in the submandibular gland was observed in apoE-deficient rat group and in none of the control group. Significant increases in vacuolization and apoptosis in acinar cells were observed in apoE-deficient rats, as compared to control rats (P<0.05). The number of active caspase-3-positive cells was also higher in the apoE-deficient rat group when compared with the control group (P<0.01).

CONCLUSIONS

According to our results, hyperlipidemia induced apoptosis in apoE-deficient rat submandibular glands. Oxidized LDL generation in case of hyperlipidemia may trigger off a reaction of apoptotic acinar cells with vacuolization in the submandibular glands.