Purpose: Patients receiving chemotherapy may experience ocular discomfort and dry eye-like symptoms; the latter may be neuropathic in nature. This study assessed corneal and somatic hypersensitivity in male rats treated with paclitaxel and whether it was relieved by nicotinamide riboside (NR).
Methods: Corneal sensitivity to tactile and chemical stimulation, basal tear production, and sensitivity of the hindpaw to tactile and cool stimuli were assessed before and after paclitaxel in the absence and presence of sustained treatment with 500 mg/kg per os NR.
Nicotinamide riboside (NR) is a vitamin B3 precursor of NAD that blunts diabetic and chemotherapy-induced peripheral neuropathy in preclinical models. This study examined whether NR also blunts the loss of intraepidermal nerve fibers induced by paclitaxel, which is associated with peripheral neuropathy. The work was conducted in female rats with N-methyl-nitrosourea (MNU)-induced tumors of the mammary gland to increase its translational relevance, and to assess the interaction of NR with paclitaxel and NR's effect on tumor growth.
View Article and Find Full Text PDFInjury to sensory afferents may contribute to the peripheral neuropathies that develop after administration of chemotherapeutic agents. Manipulations that increase levels of nicotinamide adenine dinucleotide (NAD) can protect against neuronal injury. This study examined whether nicotinamide riboside (NR), a third form of vitamin B3 and precursor of NAD, diminishes tactile hypersensitivity and place escape-avoidance behaviors in a rodent model of paclitaxel-induced peripheral neuropathy.
View Article and Find Full Text PDFThis study examined whether peripheral inflammatory injury increases the levels or changes the disposition of substance P (SubP) in the rostral ventromedial medulla (RVM), which serves as a central relay in bulbospinal pathways of pain modulation. Enzyme immunoassay and reverse transcriptase quantitative polymerase chain reaction were used to measure SubP protein and transcript, respectively, in tissue homogenates prepared from the RVM and the periaqueductal gray (PAG) and cuneiform nuclei of rats that had received an intraplantar injection of saline or complete Freund's adjuvant (CFA). Matrix-Assisted Laser Desorption/Ionization Time of Flight analysis confirmed that the RVM does not contain hemokinin-1 (HK-1), which can confound measurements of SubP because it is recognized equally well by commercial antibodies for SubP.
View Article and Find Full Text PDFBackground: Real-time quantitative PCR (qPCR) is a technique frequently used to measure changes in mRNA expression. To ensure validity of experimental findings, it is important to normalize the qPCR data to reference genes that are stable and unaffected by the experimental treatment to correct for variability among samples. Unlike in some models of neuropathic pain, reference genes for models of inflammatory injury have not been validated.
View Article and Find Full Text PDF