Objective To evaluate the role of spinal Toll-like receptor 4 (TLR4) signaling pathway in the development of inflammatory pain in rats.Methods Thirty-six adult male Sprague-Dawley rats were divided into 3 groups (n=12 each) using a random number table:control group,inflammatory pain group and TLR4 signaling pathway inhibitor epigallocatechin gallate (EGCG) group (EGCG group).Inflammatory pain was induced by injecting 50 μl of complete Freund's adjuvant (CFA) into the ankle joint cavity of the left hindpaw of rats anesthetized with isoflurane.At 1-3 days after injection of CFA,EGCG 30 μg was intrathecally injected once a day in group EGCG.At 1,3 (30 min after intrathecal injection),5and 7 days after injection of CFA,the mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured.The ipsilateral L4.5 segments of the spinal cord were removed at 3 days after CFA injcction for determination of TLR4 expression (by Western blot) and contents of tumor necrosis factor-alpha (TNF-oα),interleukin-6 (IL-6) and IL-1β in the spinal dorsal horn (by enzymelinked immunosorbent assay).Results Compared with control group,the MWT was significantly decreased and the TWL was shortened at each time point after injection of CFA,the expression of TLR4 in the spinal dorsal horn was up-regulated,and contents of TNF-α,IL-6 and IL-1β in the spinal dorsal horn were increased in inflammatory pain group (P＜ 0.05),and no significant change was found in the parameters mentioned above in EGCG group (P＞0.05).Compared with inflammatory pain group,the MWT was significantly increased and the TWL was prolonged at each time point after injection of CFA,the expression of TLR4 in the spinal dorsal horn was down-regulated,and contents of TNF-α,IL-6 and IL-1β in the spinal dorsal horn were decreased in EGCG group (P＜0.05).Conclusion Spinal TLR4 signaling pathway is involved in the development of inflammatory pain in rats.

Objective:To investigate the effects of osteocalcin (BGP) on bone growth and development and the expression levels of related hormones in offspring rats under the intervention of sodium fluoride.Methods:Twenty-four clean female SD rats and 24 clean male SD rats were selected, weighing 180-220 g, and the rats were mated in a 1∶1 cage for 10 d. The fluorosis rat model was established by drinking the fluorosis water method, female rats were divided into 3 groups according to body weight by random number table method, each group of 8 rats, including the high-dose, low-dose and control groups, with sodium fluoride of 200, 100, 0 mg/L in drinking water. The female rats were exposed to fluoride from the 0th day of pregnancy to the 3rd week after the offspring rats were born (before weaning). After weaning, 10 male offspring rats were selected from each group and continued to be exposed to fluoride in the same amount and manner until the 12th week after birth. The body weight and length of the offspring rats were measured every week before weaning and every two weeks after weaning. Enzyme-linked immunosorbent assay (ELISA) was used to detect the serum BGP, parathyroid hormone (PTH), calcitonin (CT), and alkaline phosphatase (ALP) contents in the offspring rats of each group exposed to fluoride for 12 weeks.Results:In the 2nd week of fluoride exposure, the body weights [(27.25 ± 3.57), (26.27 ± 4.48) g] and body lengths [(6.92 ± 0.46), (6.50 ± 0.54) cm] of the low-dose and high-dose groups were lower than those of the control group [(31.32 ± 3.62) g, (7.19 ± 0.26) cm, P < 0.05], but there were no significant differences in body weights and lengths between the high-dose group and the low-dose group ( P > 0.05). From the 3rd week of fluoride exposure, the body weight and length of the high-dose group were lower than those of the low-dose group and the control group ( P < 0.05). Serum BGP, PTH and ALP contents [(5.42 ± 0.26) mg/L, (157.53 ± 32.21) ng/L, (36.62 ± 6.01) U/L] in the control group were lower than those of the low-dose group [(6.15 ± 0.29) mg/L, (212.26 ± 51.97) ng/L, (50.68 ± 6.11) U/L] and high-dose group [(7.31 ± 0.77) mg/L, (274.21 ± 60.32) ng/L, (74.99 ± 9.08) U/L], and CT content [(182.40 ± 17.39) ng/L] was higher than those of the low-dose and high-dose groups [(135.77 ± 14.06), (70.09 ± 13.49) ng/L], and the differences were statistically significant ( P < 0.05); serum BGP, PTH and ALP contents in the high-dose group were higher than those in the low-dose group, and the CT content was lower than that in the low-dose group ( P < 0.05). Conclusion:Sodium fluoride may be involved in regulating the expression of related hormones by promoting the secretion of BGP, thereby affecting the bone growth and development of offspring rats.