Effects of intranasal and intramuscular administration of butorphanol and zolazepam-tiletamine combination on intraocular pressure and tear secretion in New Zealand White rabbits.

This study aimed to compare the effect of intranasal (IN) and intramuscular (IM) administration of butorphanol and zolazepam-tiletamine (ZT) combination on intraocular pressure (IOP) and tear secretion (TS) in rabbits. Fourteen healthy male New Zealand White rabbits weighing 3.05 ± 0.72 kg, aged between 1 and 2 years old, were included in the study. Animals randomly received 0.5 mg/kg butorphanol and 15 mg/kg ZT combination either with IN or IM administration. IOP and TS were measured at baseline (T0), and followed by 5, 15, 30, 45, and 60 min after drug administration. The sedation variables, the time to onset of sedation, duration of sedation, and sedation scores were also recorded. The route of administration for the butorphanol and ZT combination had no significant effect on the mean IOP (p = .301) and TS (p = .445). Furthermore, there were no significant changes observed in the IOP (p = .472) and TS (p = .348) over time. The time to onset of sedation was earlier in the IN group (4.57 ± 0.79 min) than in the IM group (5.86 ± 0.9 min; p = .0004). The duration of sedation was significantly longer for IM (57.43 ± 3.41 min) compared with IN (45.0 ± 1.91 min; p < .0001). No significant difference in the sedation score was observed between groups at all time points. In conclusion, both IN and IM administration of the butorphanol and ZT combination in rabbits had similar effects on IOP and TS.

Comparative evaluation of platelet-rich plasma, autologous blood serum, and umbilical cord serum for corneal healing after penetrating keratoplasty in New Zealand rabbits.

This study aimed to evaluate the effects of platelet-rich plasma (PRP), autologous blood serum (ABS), and umbilical cord serum (UCS) on corneal healing following penetrating keratoplasty (PK). A total of 120 New Zealand white rabbits, forty were designated as donors, while the remaining eighty rabbits were randomly divided into four groups after undergoing PRP Group (n = 20), ABS Group (n = 20), UCS Group (n = 20) and Control Group (n = 20). Corneal opacity score, corneal vascularization, corneal staining, histopathological analysis, and immunohistochemical analysis (including CD4+, CD8+, and major histocompatibility complex [MHC] II) were assessed at postoperative 1, 2, 3, and 12 weeks. The results showed that corneal opacity score and corneal vascularization did not differ significantly among the groups. However, corneal staining was found to be statistically higher in the PRP group (0.40 ± 0.60) compared to the other groups (p = 0.011). Immunohistochemical examination revealed no significant differences in CD4+, CD8+, and MHC II levels among the groups. Notably, in all groups, CD4+, CD8+, and MHC II levels were significantly higher at 12 weeks compared to other time points. PRP, ABS, and UCS demonstrated positive effects on corneal healing after PK. However, among the three products, PRP exhibited a superior healing effect compared to ABS and UCS crucial in the postoperative period following PK procedures, as they significantly impact visual quality, graft transparency, graft survival, and prevention of stromal resorption caused by infections. Despite the avascular nature of the cornea and its immune privilege, failure to resolve epithelial defects (ED) commonly observed after PK can result in irreversible scarring and ulceration, leading to graft rejection. While epithelial defects are observed in 14-100% of cases on the first postoperative day, approximately 3-7% of them persist as non-healing ED in subsequent periods. In conclusion, our study demonstrated that PRP, ABS, and UCS have a positive effect on corneal healing after PK.

Comparing the effects of intraocular pressure and tear production measurements in horses in two different environments: Horse stable and medical barn.

BACKGROUND: To date, there are no studies on the impact of two distinct environments-one familiar to the horse and another unfamiliar-on intraocular pressure (IOP) and tear production. OBJECTIVES: To compare the measured IOP and tear production values in horses between a horse stable and a medical barn. STUDY DESIGN: Cross-over. METHODS: Thirty healthy male Arabian horses, aged 6.88 ± 3.34 years were used. IOP and tear production measurements were assessed in both the horse stable and the medical barn, with a paired Student's t-test and Bland-Altman analysis conducted for comparison and agreement, respectively. RESULTS: A significant increase in IOP was observed in the medical barn (34.2 ± 6.8 mmHg) compared with the horse stable (29.5 ± 7.2 mmHg, p = 0.02). However, no statistically significant difference in tear production was found between horse stable (22.1 ± 2.8 mm/min) and medical barn (23.6 ± 3.4 mm/min) (p = 0.09). The standard error of the slope was 0.36 for the IOP measured in the medical barn, indicating a difference of -4.7 mmHg compared with the IOP measured in the horse stable (p = 0.02). The bias was fitted to y = -7.9350 + 0.1003x. The standard error of the slope was 0.39 for the tear production measured in the medical barn, indicating a difference of -1.5 mm/min compared with the tear production measured in the horse stable (p = 0.09). The bias was fitted to y = 6.1530 + -0.3367x. MAIN LIMITATIONS: The absence of horses with ocular disorders and an assessment of the potential impact of transportation. CONCLUSIONS: A notable increase in IOP was observed in the medical barn compared with the horse stable, while tear production exhibited no significant variance between the two environments. The Bland-Altman analysis highlighted a discrepancy in IOP measurements in the horse stable, emphasising the potential influence of the environment on ocular parameters in horses.

Effects of gabapentin on intraocular pressure, tear production and horizontal pupil diameter in New Zealand White rabbits.

BACKGROUND: This study aimed to investigate the effects of gabapentin on various ocular parameters in New Zealand White rabbits. METHODS: A randomised, placebo-controlled crossover study design was employed. Eight New Zealand White rabbits were randomly assigned to receive either oral gabapentin at a dosage of 15 mg/kg or an oral placebo, with a 1-week washout period between treatments. Intraocular pressure, tear production and horizontal pupil diameter were measured at baseline (T0) and at 30, 60, 90, 120, 180, 240 and 360 minutes after drug administration. Physiological and behavioural changes were also recorded for both treatments following drug administration. RESULTS: The administration of gabapentin did not have any significant effects on the ocular parameters measured in this study. However, the rabbits exhibited some muscle relaxation with partially closed eyes during handling, and they were slightly easier to remove from the cage when treated with gabapentin compared to the placebo treatment. LIMITATIONS: In this study, the ocular effects of gabapentin were assessed in only a small number of healthy rabbits. These effects may differ in rabbits with pre-existing eye conditions or in those receiving other medications. CONCLUSIONS: Our findings suggest that gabapentin treatment does not have a significant impact on intraocular pressure, tear production or horizontal pupil diameter in rabbits.