Antinociceptive effects of cefadroxil and ceftriaxone in experimental animal models of pain.

BACKGROUND: As an "off-target" effect, cephalosporins can enhance glutamate transporter-1 expression in astrocytes to recycle glutamate from synaptic cleft, and exhibited analgesic properties in animals and humans with chronic pain. METHODS: In the present study, we focused on making a side-by-side comparison of the analgesic potentials of cefadroxil and ceftriaxone, using rodent models of peripheral neuropathic pain, inflammatory pain and incisional pain. Microdialysis technique was adopted to validate the in vivo glutamate regulatory properties of these two drugs in central nervous system. RESULTS: We have shown that cefadroxil and ceftriaxone are beneficial in a variety of pain scenarios, without inducing observable side effects. The two cephalosporins worked better on neuropathic pain, rather than inflammatory pain or incisional pain, suggesting nociceptive system was differentially affected. Further, microdialysis has confirmed that cephalosporins can effectively reverse the elevated levels of glutamate in brain of animals with neuropathic pain. CONCLUSIONS: The outcome of this study may guide us to identify a molecular skeleton derived from cefadroxil, based on which we could possibly develop new non-antibiotic analgesic compounds with glutamate recycling properties.

The common neurological basis and targeted therapeutic approaches for chronic pain and opioid addiction.

Chronic pain and drug addiction seriously threaten human health and generate a large loss of labor. Most highly addictive drugs are derived from opioids, which have severe side effects and are difficult to quit completely. On the other hand, opioid analgesics are widely used in detoxification for opioid addiction. These opioids are effective for controlling acute withdrawal symptoms, but can be problematic under long-term usage as maintenance therapy. Both chronic pain and opioid abuse are related to neurotransmitters and central reward pathways in the brain. As to provide new weapons for defending human health, this article summarized the similarities and differences between chronic pain and opioid addiction, based on their common neurobiological basis, and discussed the breakthroughs in targeted therapeutic approaches. Furthermore, we have brought out an innovative and integrative therapeutic scheme by combining drugs, medical devices, and phycological / behavioral therapies, according to the patient's individual situation, aiming at achieving better effects against these two types of diseases.

Calreticulin as an Adjuvant In Vivo to Promote Dendritic Cell Maturation and Enhance Antigen-Specific T Lymphocyte Responses against Melanoma.

An endoplasmic reticulum resident protein, calreticulin (CRT), participates in many cellular processes. CRT is a tumor-associated antigen with an important role in antitumor immunity. Previously, we reported that the recombinant CRT fragment 39-272 (CRT/39-272) exhibited superior immunobiological activity, activating macrophages to release cytokines and promoting dendritic cell (DC) maturation. However, the effect of CRT/39-272 in vivo, especially its adjuvant effect on in vivo antitumor immune responses, was not fully investigated. In this study, we constructed a fusion protein linking CRT/39-272 to an ovalbumin (OVA) peptide (residues 182-297, OVAp) and used the fusion protein (OVAp-CRT) to examine the adjuvant effect of CRT. We investigated whether CRT/39-272 could induce bone marrow-derived DC maturation and strongly promote the proliferation of OVA-specific T cells in vitro. Compared with OVAp, OVAp-CRT induced stronger antigen-specific T lymphocyte responses, including antigen-specific T cell proliferation, interferon-γ secretion, and cytotoxic T lymphocyte responses. OVAp-CRT-immunized mice generated significantly increased OVAp-specific antibody and CD4+/CD8+ memory T cells, which mediated long-term protective effects. OVAp-CRT upregulated CD40, CD80, and CD86 expressions in splenic conventional DCs. Furthermore, OVAp-CRT protected immunized mice against OVA-expressing B16 melanoma cells in vivo. Moreover, mice that were adoptively transferred with OVAp-CRT-pulsed DCs showed inhibited tumor growth and prolonged mouse survival. Our results demonstrate that CRT/39-272 can be used as a potential new adjuvant for tumor vaccines, and this finding may be useful in tumor vaccine development.

[The effect of procyanidin on periprosthetic osteolysis caused by TCP wear particles in the mouse calvaria and its mechanism].

OBJECTIVE: To investigate the protective effects of procyanidin on periprosthetic osteolysis caused by tricalcium phosphate (TCP) wear particles in the mouse calvaria and its mechanism. METHODS: Forty-eight male ICR mice were randomly divided into sham group, TCP group, and procyanidin (0.2 mg/kg, 1 mg/kg, 5 mg/kg)-treated group (n=12). A periprosthetic osteolysis model in the mouse calvaria was established by implanting 30 mg of TCP wear particles onto the surface of bilateral parietal bones following removal of the periosteum. On the 2nd day post-operation, procyanidin (1 mg/kg, 5 mg/kg) was locally injected to the calvaria under the periosteum every other day. After 2 weeks, all the mice were sacrificed to collect the blood samples and the calvaria. Periprosthetic osteolysis and osteoclastogenesis in the mouse calvaria were observed by tartrate resistant acid phosphatase (TRAP) staining and HE staining. mRNA levels of TRAP, capthesin K, c-Fos and NFATc1 in the periprosthestic bone tissue were examined by real-time fluorescence quantitative PCR. Serum contents of total anti-oxidation capacity (T-AOC) and MDA, and superoxide dismutase (SOD) activity were determined by chemical colorimetry. Protein expressions of autophagic biomarkers such as Beclin-1 and LC-3 in periprosthetic bone tissue of the calvaria were examined by Western blot. RESULTS: Compared with sham group, periprosthetic osteolysis, osteoclastogenesis, mRNA levels of TRAP, capthesin K, c-Fos and NFATc1, and serum MDA content were increased significantly in the TCP group (P＜0.05), whereas serum T-AOC level and SOD activity were decreased. The protein expressions of Beclin-1 and LC-3, and the conversion of LC3-II from LC3-I were both up-regulated markedly in the mouse calvaria of TCP group (P＜0.05). Compared with TCP group, osteolysis, osteoclastogenesis, mRNA levels of TRAP, capthesin K, c-Fos and NFATc1 and serum MDA content were decreased obviously in the procyanidine group (P＜0.05), serum T-AOC level and SOD activity were increased, the expressions of Beclin-1 and LC-3, and the conversion of LC3-II from LC3-I were down-regulated obviously in the mouse calvaria of procyanidin group (P＜0.05). CONCLUSION: Procyanidin has a protective effect of periprosthetic osteolysis caused by TCP wear particles in the mouse calvaia, its mechanism may be mediated by inhibition of oxidative stress and autophagy.