Intrathecal implantation surgical considerations in rodents; a review.

Intrathecal access in humans is a routine clinical intervention. However, intrathecal access is limited to drug delivery purposes in rodents, and intrathecal implantation is not a common surgical practice. Preclinically, we have successfully adopted different intrathecal implantation surgical methods for different implant materials in rodents. However, employing the appropriate intrathecal implantation method is a challenging process for surgeons, which includes several steps such as preoperative evaluations and postoperative care. The aim of this review is to define and compare the major documented surgical approaches applicable for intrathecal implantation in rodents along with the associated side effects, as well as highlighting the critical preoperative and postoperative considerations. Overall, this review will provide surgeons with the principles of intrathecal implantation approaches applicable for different implant materials.

In vivo intrathecal IL-1ß quantification in rats: Monitoring the molecular signals of neuropathic pain.

BACKGROUND: Neuropathic pain, or pain after nerve injury, is a disorder with a significant reliance on the signalling of cytokines such as IL-1ß. However, quantifying the cytokine release repeatedly over time in vivo is technically challenging. AIM: To evaluate if changes in IL-1ß are correlated with the presentation of mechanical allodynia over time, by repeatedly quantifying intrathecal IL-1ß concentrations following chronic constriction injury of the sciatic nerve in rats. Also, to establish any possible correlation between biochemical spinal marker expression and the in vivo quantification of IL-1ß. Finally, to assess the expression of the mature IL-1ß in lumbar spinal cord samples. METHOD: The Chronic Constriction Injury model (CCI) was used to initiate nerve injury in male Sprague Dawley rats and the generation of behavioural mechanical allodynia was quantified. Using an indwelling intrathecal catheter, a stainless steel (SS) wire biosensing device was repeatedly introduced to quantify intrathecal IL-1ß concentrations at three timepoints of 0, 7, and 14 days post CCI. Fixed spinal cord samples (L4-L5), collected on day 14, were imaged for the expression of glial fibrillary acidic protein (GFAP, astrocytes) and ionized calcium binding adaptor molecule 1 (IBA1, microglia). Snap frozen spinal cord tissues (L4-L5) were also processed for western blot analysis. RESULTS: Using the novel SS based biosensing device we established that CCI caused a significant increase in intrathecal IL-1ß concentrations from day 0 to day 7 (p = 0.001) and to day 14 (p < 0.0001), while the sham group did not show any significant increase. We also further showed that the degree of mechanical allodynia correlated positively with the increase in the intrathecal concentration of IL-1ß in the active CCI animals (p = 0.0007). While there was a significant increase in the ipsilateral GFAP expression in injured animals compared to sham animals (p = 0.03), we did not find any significant correlation between in vivo IL-1ß concentration on days 7 and 14 and the area of dorsal horn GFAP or IBA1 positive structures on day 14. The result of western blot analysis of whole lumbar spinal cord revealed that there was no significant change (p = 0.7579) in IL-1ß expression on day 14 in the CCI group compared to the sham group. CONCLUSION: For the first time we have established that the SS based immunosensing platform technology can repeatedly sample the intrathecal space for bioactive peptides, such as IL-1ß. Using this novel approach, we have been able to establish the correlation of the intrathecal concentration of IL-1ß with the extent of mechanical allodynia, providing a molecular biomarker of the degree of the exaggerated pain state.

A Method for in Vivo Quantification Of Cytokine IL-1ß In The Rat Intrathecal Space.

IL-1ß is a potent pro-inflammatory cytokine critical to multiple pathologies in the central nervous system (CNS). Quantification of IL-1ß in vivo is challenging due to pM range of IL-1ß released in the spinal cord and also the terminal nature of cerebrospinal fluid (CSF) sampling in rodents. Herein we developed a robust in vivo device on stainless steel suitable for detection of IL-1ß in the spinal cord of rats. This approach offers high sensitivity (3.2 pg mL-1) and specificity to IL-1ß. Also, a modified lumbar puncture method was employed to implant the device in the intrathecal space of male Sprague-Dawley (SD) rats under short-acting anesthesia, allowing minimal invasiveness, which provided the possibility of repeated measurement of IL-1ß in the same animal. Our biosensing technology and the surgical method provide a universal platform for in vivo detection of diverse analytes in longitudinal, within-subject studies in the intrathecal space of rats to reduce the required number of experimental animals.

Sodium benzoate and potassium sorbate preservatives in food stuffs in Iran.

A high-performance liquid chromatography method was applied for the determination of the levels of benzoate and sorbate in 400 food samples, including pickled cucumbers, canned tomato pastes, sour cherry jams, soft drinks, fruit juices and dairy products (UF-Feta cheeses, Lighvan cheeses, lactic cheeses, yogurts and doogh). The results showed that 270 (67.5%) of all samples contained benzoate ranging from 11.9 to 288.5 mg kg(-1) in lactic cheese and fruit juice, respectively. The levels of sorbate in 98 (24.5%) of the samples were 20.1 to 284.3 mg kg(-1) in doogh and fruit juice, respectively. Moreover, benzoate was detected in all dairy products ranging from 11.9 mg kg(-1) in lactic cheese to 91.2 mg kg(-1) in UF-Feta cheese. A low concentration of benzoate could originate naturally, due to specific biochemical mechanisms during cheese, yogurt and doogh maturation. In conclusion, a minimum level for benzoate in dairy products should be defined in the legislation.