Animal treatment
All animal procedures and study protocols were double-blind and carried
out in strict accordance with the recommendations of the Guide for the
Institutional Animal Care and Use Committee of Zhejiang University
Medical Center. Mice were housed in cages at a controlled temperature
(22 ± 0.1 °C) and humidity (50 ± 10%) with a 12-h light/dark cycle and
provided with free access to food and water. All surgeries were
performed under chloral hydrate anaesthesia, and all efforts were made
to minimize animal suffering. All mice were killed by
CO2 asphyxiation. Animals were randomised for treatment.
Specific pathogen‐free ICR
mice
(22-25 g), aged 4 weeks (male, 8; female, 8), were purchased from the
Experimental Animal Center of the Zhejiang Academy of Medical Sciences
[SCXK (Zhe) 2014-0001]. Nude mice (5 weeks old, male) were obtained
from Beijing Vital River Laboratory Animal Technology Company (Beijing,
China; SCXK [Jing] 2012‐0001) and maintained under specific
pathogen-free (SPF) conditions. After adaptive feeding for one week, the
nude mice were subcutaneously injected with HT29 cells into the rear
flanks (1 × 107 cells/side). Nude mice with tumours of
average volume = 50-60 mm3 were selected for the
experiments.
To evaluate the neuroprotective effects of L-THP, mice with one-week
adaptive feeding, were randomly allocated into 6 groups with 16 mice
each (half male and half female): vehicle group, OXA-alone group, OXA
and L-THP co-treatment groups, and L-THP-alone group. OXA was
intravenously injected (iv, 8 mg/kg) twice a week for a total of
four weeks (days 1, 4, 8, 11, 15, 18, 22, and 25). For the co-treatment
groups, the mice were iv injected with 5% glucose solution
containing L-THP (5-20 mg/kg) and OXA (8 mg/kg). Mice in the vehicle or
L-THP-alone groups received equal volumes of 5% glucose without or with
L-THP (10 mg/kg), respectively. The mouse behaviour and body weight were
monitored and recorded after every administration. Twenty-four hours
after the final administration, the animals were sacrificed and the DRGs
were collected for analysis.
For evaluation of the antitumour activity, the tumour-bearing nude mice
were allocated into 4 groups to evaluate whether L-THP co-treatment (10
and 20 mg/kg) would impair the antitumour efficacy of OXA (8 mg/kg):
vehicle group, OXA-alone group, and OXA and L-THP co-treatment groups.
Drugs were administered intravenously every two days for two weeks (days
1, 3, 5, 7, 9, 11, and 13), and the body weight and tumour size were
monitored. Twenty-four hours after the final administration, the animals
were sacrificed, and the tumours were collected, weighted, and stored
for analysis. The tumour sizes were calculated according to the
following formula: tumour size =a*b2/2 , where a
is the long side of the tumour and b is the short side
of the tumour.