Oral

[O3-D-PM1-03] Age-related alteration of the importance of parotid CD36 in mouse salivary secretion

〇Keitaro Satoh¹, Yuta Ohno², Haruna Nagase², Masanori Kashimata², Kazunori Adachi¹ (1. Div Pharmacol, Meikai Univ Sch Dent, 2. Dept Pharmacol, Asahi Univ Sch Dent)

Keywords:脂肪酸輸送体、耳下腺、唾液分泌

There are many causes for decreased salivary secretion, including aging. In rodents, such as mice and rats, the aging-related accumulation of adipose tissue increases around the parotid gland is observed. Triglycerides are stored in adipose tissue and metabolized into fatty acids and glycerol as needed in the cells. It has been reported that CD36, a fatty acid transporter, is expressed on the tongue, playing a role in some taste reception by the uptake of dietary fatty acids such as palmitate acid. However, there are few reports on CD36 in salivary glands. In this study, we investigated the temporal alteration of CD36 function in salivary secretion using mainly in vivo mouse model. In salivary glands of male BALB/c mice, CD36 mRNA was highly expressed in the parotid gland compared with submandibular and sublingual glands. In immunohistochemistry, CD36 protein was expressed more in the ducts than in the acinus of the parotid gland. The salivary secretion was induced by pilocarpine (0.5 mg kg⁻¹, i.p.) treatment in 8-, 48-, and 72-week mice; however, the amount of secreted saliva was reduced by aging. Pretreatment of CD36 inhibitor (sulfosuccinimidyl oleate: SSO, 16.8 mg kg^-1, i.p.) reduced pilocarpine-induced salivary secretion, and the inhibitory effect of SSO on the salivary secretion was also reduced by aging. In addition, the involvement of CD36 in the uptake of fatty acid to the parotid gland of 8-week mice was confirmed by in vitro [³H]-palmitic acid uptake assay. These results indicate that CD36 in parotid ducts was highly related to salivary secretion in younger animals. Moreover, the absence of the relationship between the impairment of CD36 function and the salivary secretion in elder animals was suggested.