Review for 10.1186/1471-230X-11-125 (2011)

Reviewer's report
Title:Ringer's Lactate improves liver recovery in a murine model of
acetaminophen toxicity
Version: 1Date:24 January 2011
Reviewer: Cynthia Ju
Reviewer's report:
The current study investigated whether RLS can improve liver recovery from
APAP-induced acute liver injury (ALI). The data demonstrated that repeated RLS
treatments initiated at 2 hr post-APAP administration can decrease liver injury.
The authors also observed increased NF-kB activation and cyclin D1 expression
by RLS at later time point (72 hr) after ALI. The findings led to the conclusion that
RLS, via promoting hepatocyte proliferation, improves liver recovery from APAP
hepatotoxicity. Although the decrease of ALT and AST levels at 72 hr suggests a
protective effect of RLS, the histological improvement was not obvious.
Furthermore, it is not convincing that RLS has a significant effect on hepatocyte
proliferation. No data were presented to directly examine the effect of RLS on
hepatocyte proliferation. Specific comments and questions are the following:
Major Compulsory Revisions
1. After APAP treatment, hepatocyte proliferation occurs quite rapidly. Peak BrdU
incorporation can be as early as 24 hr post-APAP. Yet, all the measurements
were conducted at 72 hr post-APAP in the current study even though RLS was
given at 2 hr after APAP treatment. The experiments (TNFa, NF-kB and cyclin
D1 measurements) need to be repeated for earlier time points (eg. 24hr and 48
hr post-APAP).
2. It is critical that the authors directly examine hepatocyte proliferation (e.g.
BrdU incorporation), establish its kinetics and investigate whether RLS treatment
has any effect. This information is necessary in order to determine whether the
rest of the data presented are relevant.
3. Were all the data shown obtained from the same 6 mice/group? The authors
need to clarify whether the experiments were conducted more than once and that
the results were similar to those presented. If the experiments were only
performed once, they need to be repeated at least one more time. Although the
results were neither shown nor discussed, the authors did mention (in the
Method) another set of experiments where RLS was given for 24 hr (rather than
72 hr). But, that does not count for a repetition, as it is a different experiment.
4. For the liver histological evaluation (Fig.2), it would be more convincing if the
authors can quantify the number and/or size of necrotic areas.
Minor Essential Revisions
5. In the Discussion (para 1), the authors stated that “hepatic congestion was
ameliorated” after RLS treatment. It may be the main explanation for the
hepato-protective effect of RLS, which curbs the progression of liver injury rather
than promotes hepatocyte proliferation. The data need to be shown.
6. The ALT levels at 24 hr post-APAP were higher than 50,000 U/L. It is very
curious that the animals survived at such high levels of serum ALT activities. The
authors did mention that the data were obtained from 6 surviving animals per
group. Please provide information on the percentage of survival. Was RLS only
protective if the APAP-induce toxicity is very high? The authors should repeat the
experiment with a lower dose of APAP and examine whether RLS is still
protective.
7. As the authors stated, TNFa is important in priming hepatocytes. Therefore, if
induction of TNFa by RLS has a role in promoting hepatocyte proliferation, one
would expect to see increases in TNFa expression levels prior to proliferation.
However, the only time point when RLS caused an increase in TNFa was 72 hr,
negating the importance of TNFa. These data need to be discussed.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I declare that I have no competing interests.